Initial commit

.gitignore

@@ -0,0 +1,6 @@
+.idea
+*.o
+*.gbm
+gbmconv
+game.exe
+game.img

Makefile

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+HOSTCXX:=$(CXX)
+
+ifeq ($(TARGET),SDL)
+# SDL
+CC=gcc
+CXX=g++
+LD=g++
+STRIP=strip
+
+SDL_INCLUDE=$(shell pkg-config --cflags sdl2)
+SDL_LIBS=$(shell pkg-config --libs sdl2)
+
+CFLAGS=-g -DBUILD_SDL $(SDL_INCLUDE)
+CXXFLAGS=$(CFLAGS)
+LDFLAGS=
+LDLIBS=$(SDL_LIBS) -lstdc++
+EXE=game
+EXTRA_FILES=
+SYSTEM=SDL
+else ifeq ($(TARGET),SDLWIN)
+# SDL on Windows
+CC=i686-w64-mingw32-gcc
+CXX=i686-w64-mingw32-g++
+LD=i686-w64-mingw32-g++
+STRIP=i686-w64-mingw32-strip
+
+SDL_INCLUDE=-I../SDL2-2.32.10/i686-w64-mingw32/include/SDL2
+SDL_LDFLAGS=-L../SDL2-2.32.10/i686-w64-mingw32/lib
+SDL_LIBS=-lmingw32 -lSDL2main -lSDL2
+
+CFLAGS=-g -DBUILD_SDL $(SDL_INCLUDE) -m32
+CXXFLAGS=$(CFLAGS)
+LDFLAGS=$(SDL_LDFLAGS) -mwindows
+LDLIBS=$(SDL_LIBS) -lstdc++
+EXE=game.exe
+EXTRA_FILES=../SDL2-2.32.10/i686-w64-mingw32/bin/SDL2.dll
+EXTRA_FILES+=/usr/lib/gcc/i686-w64-mingw32/10-win32/libgcc_s_dw2-1.dll
+EXTRA_FILES+=/usr/lib/gcc/i686-w64-mingw32/10-win32/libstdc++-6.dll
+SYSTEM=SDL
+else ifeq ($(TARGET),SDLWIN64)
+# SDL on Windows
+CC=x86_64-w64-mingw32-gcc
+CXX=x86_64-w64-mingw32-g++
+LD=x86_64-w64-mingw32-g++
+STRIP=x86_64-w64-mingw32-strip
+
+SDL_INCLUDE=-I../SDL2-2.32.10/x86_64-w64-mingw32/include/SDL2
+SDL_LDFLAGS=-L../SDL2-2.32.10/x86_64-w64-mingw32/lib
+SDL_LIBS=-lmingw32 -lSDL2main -lSDL2
+
+CFLAGS=-g -DBUILD_SDL $(SDL_INCLUDE) -m64
+CXXFLAGS=$(CFLAGS)
+LDFLAGS=$(SDL_LDFLAGS) -mwindows
+LDLIBS=$(SDL_LIBS) -lstdc++
+EXE=game.exe
+EXTRA_FILES=../SDL2-2.32.10/x86_64-w64-mingw32/bin/SDL2.dll
+EXTRA_FILES+=/mingw64/bin/libgcc_s_seh-1.dll
+EXTRA_FILES+=/mingw64/bin/libstdc++-6.dll
+SYSTEM=SDL
+else
+# DOS
+CC=/usr/local/djgpp/bin/i586-pc-msdosdjgpp-gcc
+CXX=/usr/local/djgpp/bin/i586-pc-msdosdjgpp-g++
+LD=/usr/local/djgpp/bin/i586-pc-msdosdjgpp-g++
+STRIP=i586-pc-msdosdjgpp-strip
+
+CFLAGS=-O3 -march=i486
+CXXFLAGS=$(CFLAGS)
+LDFLAGS=
+LDLIBS=
+EXE=game.exe
+DPMI_HOST=CWSDPMI.EXE
+EXTRA_FILES=install.bat $(DPMI_HOST)
+SYSTEM=DOS
+endif
+
+OBJ=main.o
+OBJ+=$(patsubst %.cpp,%.o,$(wildcard graphics/*.cpp))
+OBJ+=$(patsubst %.cpp,%.o,$(wildcard audio/*.cpp))
+OBJ+=$(patsubst %.cpp,%.o,$(wildcard util/*.cpp))
+OBJ+=$(patsubst %.cpp,%.o,$(wildcard scenes/*.cpp))
+
+ifeq ($(SYSTEM),SDL)
+OBJ+=$(patsubst %.cpp,%.o,$(wildcard system/sdl/*.cpp))
+else ifeq ($(SYSTEM),DOS)
+OBJ+=$(patsubst %.cpp,%.o,$(wildcard system/dos/*.cpp))
+else
+$(error Unknown SYSTEM variable:$(SYSTEM))
+endif
+
+CONVERTER_CXX=$(HOSTCXX)
+CONVERTER_EXE=gbmconv
+CONVERTER_SRC=converter.cpp
+CONVERTER_SRC+=graphics/Bitmap.cpp
+CONVERTER_SRC+=util/Files.cpp util/Bmp.cpp util/Gbm.cpp
+
+COMPILED_GFX_ASSETS=assets/font1.gbm assets/cow.gbm assets/witch.gbm
+GFX_ASSETS=assets/bg.bmp $(COMPILED_GFX_ASSETS)
+MUSIC_ASSETS=assets/rain.rad assets/getup.rad assets/spiral.rad
+
+RELEASE_FILES=$(EXE) $(GFX_ASSETS) $(MUSIC_ASSETS) $(EXTRA_FILES)
+
+FLOPPY_IMG=game.img
+
+.PHONY: all clean release debug assets floppy
+
+all: $(CONVERTER_EXE) $(EXE)
+
+clean: ; rm -rf $(OBJ) $(EXE) $(CONVERTER_EXE) $(FLOPPY_IMG) $(COMPILED_GFX_ASSETS) release debug
+
+release: all assets; $(STRIP) $(EXE) && upx $(EXE); mkdir -p release; cp -Rv $(RELEASE_FILES) release/
+
+debug: all assets; mkdir -p debug; cp -Rv $(RELEASE_FILES) debug/
+
+floppy: release; dd if=/dev/zero of=$(FLOPPY_IMG) bs=512 count=2880 && mkfs.fat -F12 $(FLOPPY_IMG) && mcopy -i $(FLOPPY_IMG) -s release/* ::
+
+$(CONVERTER_EXE): $(CONVERTER_SRC); $(CONVERTER_CXX) -o $@ $(CONVERTER_SRC)
+
+$(EXE): $(OBJ); $(LD) $(LDFLAGS) -o $@ $(OBJ) $(LDLIBS)
+
+%.o : %.c ; $(CC) $(CFLAGS) -c $< -o $@
+
+%.o : %.cpp ; $(CXX) $(CXXFLAGS) -c $< -o $@
+
+assets: $(CONVERTER_EXE) $(GFX_ASSETS)
+
+%.gbm : %.bmp %_m.bmp $(CONVERTER_EXE) ; ./$(CONVERTER_EXE) $@ $^

audio/Audio.cpp

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+#include "Audio.h"
+#include "../util/Files.h"
+
+#include "AudioPlayer.h"
+
+Audio::Audio() {
+}
+
+Audio::Audio(const char *path) {
+    loadFromFile(path);
+}
+
+Audio::~Audio() {
+    unload();
+}
+
+bool Audio::isValid() const {
+    return _data != nullptr;
+}
+
+void Audio::loadFromFile(const char *path) {
+    unload();
+    _length = Files::allocateBufferAndLoadFromFile(path, &_data);
+}
+
+void Audio::unload() {
+    if (_data) {
+        if (audioPlayer.isPlaying(*this)) {
+            audioPlayer.stopAudio(*this);
+        }
+        Files::deleteBuffer(_data);
+        _length = 0;
+    }
+}
+

audio/Audio.h

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+#ifndef GAME_AUDIO_H
+#define GAME_AUDIO_H
+
+#include <cstddef>
+
+class Audio {
+    Audio();
+    explicit Audio(const char *path);
+    ~Audio();
+
+    [[nodiscard]] bool isValid() const;
+    void loadFromFile(const char* path);
+    void unload();
+private:
+    friend class AudioPlayer;
+    [[nodiscard]] void *getData() const { return _data; }
+    size_t _length{0};
+    void *_data{nullptr};
+};
+
+
+#endif //GAME_AUDIO_H

audio/AudioPlayer.cpp

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+
+#include "AudioPlayer.h"
+
+#include "../system/Opl.h"
+#include "../system/Timer.h"
+
+AudioPlayer audioPlayer;
+
+void radPlayerWriteReg(void *p, uint16_t reg, uint8_t data) {
+    auto player = static_cast<AudioPlayer *>(p);
+    player->writeOpl(reg, data);
+}
+
+void audioPlayerOnTimer() {
+    audioPlayer.onTimer();
+}
+
+AudioPlayer::AudioPlayer() {
+    timer.setCallback(audioPlayerOnTimer);
+}
+
+AudioPlayer::~AudioPlayer() {
+    timer.setCallback(nullptr);
+}
+
+void AudioPlayer::playMusic(Music &music) {
+    stopMusic();
+
+    _currentMusic = &music;
+    _musicPlayer.Init(_currentMusic->getData(), radPlayerWriteReg, this);
+
+    auto hz = _musicPlayer.GetHertz();
+    if (hz < 0) {
+        stopMusic();
+        return;
+    }
+
+    // Start music playback
+    timer.setFrequency(hz);
+    resumeMusic();
+}
+
+void AudioPlayer::stopMusic() {
+    if (!_currentMusic) return;
+
+    _musicPlayer.Stop();
+    _paused = true;
+    _currentMusic = nullptr;
+}
+
+void AudioPlayer::pauseMusic() {
+    _paused = true;
+}
+
+void AudioPlayer::resumeMusic() {
+    if (!_currentMusic) return;
+
+    _paused = false;
+}
+
+void AudioPlayer::playAudio(Audio &audio, int priority, int flags) {
+    if (priority > AUDIO_MAX_PRIORITY) priority = AUDIO_MAX_PRIORITY;
+
+
+}
+
+bool AudioPlayer::isPlaying(const Audio &audio) {
+    for (auto &channel : _channels) {
+        if (channel.audio == &audio) return true;
+    }
+    return false;
+}
+
+void AudioPlayer::stopAudio(Audio &audio) {
+    for (auto &channel : _channels) {
+        if (channel.audio == &audio) {
+            channel.audio = nullptr;
+            channel.loop = false;
+        }
+    }
+}
+
+void AudioPlayer::stopAllAudio() {
+    for (auto &channel : _channels) {
+        channel.audio = nullptr;
+        channel.loop = false;
+    }
+}
+
+void AudioPlayer::generateSamples(uint8_t *buffer, size_t size) {
+}
+
+bool AudioPlayer::isPlaying(const Music &music) const {
+    return _currentMusic == &music;
+}
+
+void AudioPlayer::writeOpl(uint16_t reg, uint8_t data) const {
+    Opl::write(reg, data);
+}
+
+void AudioPlayer::onTimer() {
+    if (_paused) return;
+    if (!_currentMusic) return;
+
+    _musicPlayer.Update();
+}
+
+void AudioPlayer::generateSamples() {
+
+}
+

audio/AudioPlayer.h

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+#ifndef GAME_AUDIOPLAYER_H
+#define GAME_AUDIOPLAYER_H
+
+#include "Audio.h"
+#include "Music.h"
+#include "rad20player.h"
+
+#define AUDIO_CHANNELS 8
+#define AUDIO_MAX_PRIORITY 7
+
+#define AUDIO_PLAY_LOOP 0x01
+#define AUDIO_PLAY_FIXED_PRIORITY 0x02
+
+class AudioPlayer {
+public:
+    AudioPlayer();
+
+    ~AudioPlayer();
+
+    void playMusic(Music &music);
+
+    void stopMusic();
+
+    void pauseMusic();
+
+    void resumeMusic();
+
+    void playAudio(Audio &audio, int priority, int flags = 0);
+
+    bool isPlaying(const Audio & audio);
+
+    void stopAudio(Audio &audio);
+
+    void stopAllAudio();
+
+    void generateSamples(uint8_t *buffer, size_t size);
+private:
+    friend class Music;
+    friend void radPlayerWriteReg(void *p, uint16_t reg, uint8_t data);
+    friend void audioPlayerOnTimer();
+
+    RADPlayer _musicPlayer;
+    Music *_currentMusic{nullptr};
+    bool _paused{true};
+
+    struct {
+        Audio *audio{nullptr};
+        bool loop{false};
+    } _channels[AUDIO_CHANNELS];
+
+    [[nodiscard]] bool isPlaying(const Music &music) const;
+    void writeOpl(uint16_t reg, uint8_t data) const;
+    void onTimer();
+
+    void generateSamples();
+
+    void copySamples();
+};
+
+extern AudioPlayer audioPlayer;
+
+#endif //GAME_AUDIOPLAYER_H

audio/Music.cpp

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+#include "Music.h"
+
+#include "AudioPlayer.h"
+#include "../util/Files.h"
+
+Music::Music() {
+}
+
+Music::Music(const char *path) {
+    loadFromFile(path);
+}
+
+Music::~Music() {
+    unload();
+}
+
+bool Music::isValid() const {
+    return _data != nullptr;
+}
+
+void Music::loadFromFile(const char *path) {
+    unload();
+    _length = Files::allocateBufferAndLoadFromFile(path, &_data);
+}
+
+void Music::unload() {
+    if (_data) {
+        if (audioPlayer.isPlaying(*this)) {
+            audioPlayer.stopMusic();
+        }
+        Files::deleteBuffer(_data);
+        _length = 0;
+    }
+}

audio/Music.h

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+#ifndef GAME_MUSIC_H
+#define GAME_MUSIC_H
+
+#include <cstddef>
+
+class Music {
+public:
+    Music();
+    explicit Music(const char *path);
+    ~Music();
+
+    [[nodiscard]] bool isValid() const;
+    void loadFromFile(const char* path);
+    void unload();
+private:
+    friend class AudioPlayer;
+    [[nodiscard]] void *getData() const { return _data; }
+    size_t _length{0};
+    void *_data{nullptr};
+};
+
+
+#endif //GAME_MUSIC_H

audio/rad20player.h

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+#ifndef RAD20PLAYER_H
+#define RAD20PLAYER_H
+
+#include <stdint.h>
+
+//==================================================================================================
+// RAD player class.
+//==================================================================================================
+class RADPlayer {
+
+    // Various constants
+    enum {
+        kTracks             = 100,
+        kChannels           = 9,
+        kTrackLines         = 64,
+        kRiffTracks         = 10,
+        kInstruments        = 127,
+
+        cmPortamentoUp      = 0x1,
+        cmPortamentoDwn     = 0x2,
+        cmToneSlide         = 0x3,
+        cmToneVolSlide      = 0x5,
+        cmVolSlide          = 0xA,
+        cmSetVol            = 0xC,
+        cmJumpToLine        = 0xD,
+        cmSetSpeed          = 0xF,
+        cmIgnore            = ('I' - 55),
+        cmMultiplier        = ('M' - 55),
+        cmRiff              = ('R' - 55),
+        cmTranspose         = ('T' - 55),
+        cmFeedback          = ('U' - 55),
+        cmVolume            = ('V' - 55),
+    };
+
+    enum e_Source {
+        SNone, SRiff, SIRiff,
+    };
+
+    enum {
+        fKeyOn              = 1 << 0,
+        fKeyOff             = 1 << 1,
+        fKeyedOn            = 1 << 2,
+    };
+
+    struct CInstrument {
+        uint8_t             Feedback[2];
+        uint8_t             Panning[2];
+        uint8_t             Algorithm;
+        uint8_t             Detune;
+        uint8_t             Volume;
+        uint8_t             RiffSpeed;
+        uint8_t *           Riff;
+        uint8_t             Operators[4][5];
+    };
+
+    struct CEffects {
+        int8_t              PortSlide;
+        int8_t              VolSlide;
+        uint16_t            ToneSlideFreq;
+        uint8_t             ToneSlideOct;
+        uint8_t             ToneSlideSpeed;
+        int8_t              ToneSlideDir;
+    };
+
+    struct CChannel {
+        uint8_t             LastInstrument;
+        CInstrument *       Instrument;
+        uint8_t             Volume;
+        uint8_t             DetuneA;
+        uint8_t             DetuneB;
+        uint8_t             KeyFlags;
+        uint16_t            CurrFreq;
+        int8_t              CurrOctave;
+        CEffects            FX;
+        struct CRiff {
+            CEffects        FX;
+            uint8_t *       Track;
+            uint8_t *       TrackStart;
+            uint8_t         Line;
+            uint8_t         Speed;
+            uint8_t         SpeedCnt;
+            int8_t          TransposeOctave;
+            int8_t          TransposeNote;
+            uint8_t         LastInstrument;
+        } Riff, IRiff;
+    };
+
+    public:
+                            RADPlayer() : Initialised(false) {}
+        void                Init(const void *tune, void (*opl3)(void *, uint16_t, uint8_t), void *arg);
+        void                Stop();
+        bool                Update();
+        int                 GetHertz() const {  return Hertz;  }
+        int                 GetPlayTimeInSeconds() const {  return PlayTime / Hertz;  }
+        int                 GetTunePos() const {  return Order;  }
+        int                 GetTuneLength() const {  return OrderListSize;  }
+        int                 GetTuneLine() const {  return Line;  }
+        void                SetMasterVolume(int vol) {  MasterVol = vol;  }
+        int                 GetMasterVolume() const {  return MasterVol;  }
+        int                 GetSpeed() const {  return Speed;  }
+
+#if RAD_DETECT_REPEATS
+        uint32_t            ComputeTotalTime();
+#endif
+
+    private:
+        bool                UnpackNote(uint8_t *&s, uint8_t &last_instrument);
+        uint8_t *           GetTrack();
+        uint8_t *           SkipToLine(uint8_t *trk, uint8_t linenum, bool chan_riff = false);
+        void                PlayLine();
+        void                PlayNote(int channum, int8_t notenum, int8_t octave, uint16_t instnum, uint8_t cmd = 0, uint8_t param = 0, e_Source src = SNone, int op = 0);
+        void                LoadInstrumentOPL3(int channum);
+        void                PlayNoteOPL3(int channum, int8_t octave, int8_t note);
+        void                ResetFX(CEffects *fx);
+        void                TickRiff(int channum, CChannel::CRiff &riff, bool chan_riff);
+        void                ContinueFX(int channum, CEffects *fx);
+        void                SetVolume(int channum, uint8_t vol);
+        void                GetSlideDir(int channum, CEffects *fx);
+        void                LoadInstMultiplierOPL3(int channum, int op, uint8_t mult);
+        void                LoadInstVolumeOPL3(int channum, int op, uint8_t vol);
+        void                LoadInstFeedbackOPL3(int channum, int which, uint8_t fb);
+        void                Portamento(uint16_t channum, CEffects *fx, int8_t amount, bool toneslide);
+        void                Transpose(int8_t note, int8_t octave);
+        void                SetOPL3(uint16_t reg, uint8_t val) {
+                                OPL3Regs[reg] = val;
+                                OPL3(OPL3Arg, reg, val);
+                            }
+        uint8_t             GetOPL3(uint16_t reg) const {
+                                return OPL3Regs[reg];
+                            }
+
+        void                (*OPL3)(void *, uint16_t, uint8_t);
+        void *              OPL3Arg;
+        CInstrument         Instruments[kInstruments];
+        CChannel            Channels[kChannels];
+        uint32_t            PlayTime;
+#if RAD_DETECT_REPEATS
+        uint32_t            OrderMap[4];
+        bool                Repeating;
+#endif
+        int16_t             Hertz;
+        uint8_t *           OrderList;
+        uint8_t *           Tracks[kTracks];
+        uint8_t *           Riffs[kRiffTracks][kChannels];
+        uint8_t *           Track;
+        bool                Initialised;
+        uint8_t             Speed;
+        uint8_t             OrderListSize;
+        uint8_t             SpeedCnt;
+        uint8_t             Order;
+        uint8_t             Line;
+        int8_t              Entrances;
+        uint8_t             MasterVol;
+        int8_t              LineJump;
+        uint8_t             OPL3Regs[512];
+
+        // Values exported by UnpackNote()
+        int8_t              NoteNum;
+        int8_t              OctaveNum;
+        uint8_t             InstNum;
+        uint8_t             EffectNum;
+        uint8_t             Param;
+        bool                LastNote;
+
+        static const int8_t NoteSize[];
+        static const uint16_t ChanOffsets3[9], Chn2Offsets3[9];
+        static const uint16_t NoteFreq[];
+        static const uint16_t OpOffsets3[9][4];
+        static const bool   AlgCarriers[7][4];
+};
+
+#endif
+

converter.cpp

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+#include <cstdio>
+
+#include "util/Bmp.h"
+#include "util/Gbm.h"
+
+void usage() {
+    printf("Usage: gbmconv <gbm output file> <source bitmap> <source mask bitmap>\n");
+}
+
+int main(int argc, char** argv) {
+    if (argc < 4) {
+        usage();
+        return 1;
+    }
+
+    char *gbmPath = argv[1];
+    char *bmpPath = argv[2];
+    char *maskBmpPath = argv[3];
+
+    auto bitmap = Bmp::loadFromFile(bmpPath);
+    if (bitmap.GetWidth() == 0 || bitmap.GetHeight() == 0) {
+        printf("Unable to load source bitmap\n");
+        return 1;
+    }
+
+    auto maskBitmap = Bmp::loadFromFile(maskBmpPath);
+    if (maskBitmap.GetWidth() == 0 || maskBitmap.GetHeight() == 0) {
+        printf("Unable to load mask bitmap\n");
+        return 1;
+    }
+
+    if (maskBitmap.GetWidth() != bitmap.GetWidth() || maskBitmap.GetHeight() != bitmap.GetHeight()) {
+        printf("Mask bitmap must be the same size as the source bitmap\n");
+        return 1;
+    }
+
+    // Create a combined bitmap where the most significant bit is a transparency bit
+    auto combined = Bitmap(bitmap.GetWidth(), bitmap.GetHeight());
+    for (auto y = 0u; y < bitmap.GetHeight(); y++) {
+        for (auto x = 0u; x < bitmap.GetWidth(); x++) {
+            auto isTransparent = (maskBitmap.GetPixel(x, y) == 0);
+            auto pv = (isTransparent ? 0x80 : 0x00) | (bitmap.GetPixel(x, y) & 0x7f);
+            combined.SetPixel(x, y, pv);
+        }
+    }
+    for (auto i = 0u; i < 256; i++) {
+        combined.SetPaletteEntry(i, bitmap.GetPaletteEntry(i));
+    }
+
+    Gbm::writeToFile(gbmPath, combined);
+    printf("Wrote %s\n", gbmPath);
+    return 0;
+}

graphics/Bitmap.cpp

@@ -0,0 +1,78 @@
+#include "Bitmap.h"
+
+#include <algorithm>
+#include <cstdio>
+#include <cstring>
+
+Bitmap::~Bitmap() {
+    clear();
+}
+
+Bitmap::Bitmap(const Bitmap &other) {
+    copyFrom(other);
+}
+
+Bitmap & Bitmap::operator=(const Bitmap &other) {
+    if (this != &other) {
+        clear();
+        copyFrom(other);
+    }
+
+    return *this;
+}
+
+Bitmap::Bitmap(Bitmap &&other) noexcept {
+    moveFrom(std::move(other));
+}
+
+Bitmap & Bitmap::operator=(Bitmap &&other) noexcept {
+    moveFrom(std::move(other));
+
+    return *this;
+}
+
+Bitmap::Bitmap(uint16_t width, uint16_t height)
+: _width(width), _height(height), _data(new uint8_t[width * height]) {
+}
+
+Bitmap::Bitmap(uint16_t width, uint16_t height, uint8_t *data) : Bitmap(width, height) {
+    memcpy(_data, data, width * height);
+}
+
+void Bitmap::SetPaletteEntry(uint8_t index, Video::PaletteEntry entry) {
+    _pal[index] = entry;
+}
+
+Video::PaletteEntry Bitmap::GetPaletteEntry(uint8_t index) const {
+    return _pal[index];
+}
+
+void Bitmap::clear() {
+    delete[] _data;
+    _data = nullptr;
+    _width = _height = 0;
+}
+
+void Bitmap::copyFrom(const Bitmap &other) {
+    _width = other._width;
+    _height = other._height;
+    _data = new uint8_t[_width * _height];
+    for (auto i = 0; i < 256; i++) _pal[i] = other._pal[i];
+
+    memcpy(_data, other._data, _width * _height);
+}
+
+void Bitmap::moveFrom(Bitmap &&other) noexcept {
+    // Clear existing data
+    clear();
+
+    // Copy data from other
+    _data = other._data;
+    _width = other._width;
+    _height = other._height;
+    for (auto i = 0; i < 256; i++) _pal[i] = other._pal[i];
+
+    // Clear other
+    other._data = nullptr;
+    other._width = other._height = 0;
+}

graphics/Bitmap.h

@@ -0,0 +1,66 @@
+#ifndef GAME_BITMAP_H
+#define GAME_BITMAP_H
+
+#include <cstdint>
+
+#include "../system/Video.h"
+
+class Bitmap {
+public:
+    Bitmap() = default;
+
+    ~Bitmap();
+
+    Bitmap(const Bitmap& other);
+    Bitmap& operator=(const Bitmap& other);
+
+    Bitmap(Bitmap &&other) noexcept ;
+    Bitmap& operator=(Bitmap &&other) noexcept;
+
+    Bitmap(uint16_t width, uint16_t height);
+
+    Bitmap(uint16_t width, uint16_t height, uint8_t* data);
+
+    [[nodiscard]] uint8_t GetPixel(uint16_t x, uint16_t y) const {
+        return _data[y * _width + x];
+    }
+
+    void SetPixel(uint16_t x, uint16_t y, uint8_t value) {
+        _data[y * _width + x] = value;
+    }
+
+    uint8_t &operator[](uint32_t offset) {
+        return _data[offset];
+    }
+
+    const uint8_t &operator[](uint32_t offset) const {
+        return _data[offset];
+    }
+
+    void SetPaletteEntry(uint8_t index, Video::PaletteEntry entry);
+
+    [[nodiscard]] Video::PaletteEntry GetPaletteEntry(uint8_t index) const;
+
+    [[nodiscard]] uint16_t GetWidth() const {
+        return _width;
+    }
+
+    [[nodiscard]] uint16_t GetHeight() const {
+        return _height;
+    }
+
+    void clear();
+
+private:
+    uint16_t _width{0};
+    uint16_t _height{0};
+    uint8_t *_data{nullptr};
+
+    Video::PaletteEntry _pal[256]{};
+
+    void copyFrom(const Bitmap& other);
+    void moveFrom(Bitmap&& other) noexcept;
+};
+
+
+#endif //GAME_BITMAP_H

graphics/Font.h

@@ -0,0 +1,67 @@
+#ifndef GAME_FONT_H
+#define GAME_FONT_H
+
+#include "Bitmap.h"
+
+class Font {
+public:
+    Font(Bitmap *bitmap, unsigned w, unsigned h, unsigned minCode = 32, unsigned maxCode = 127)
+    : _font(bitmap), _w(w), _h(h), _minCode(minCode), _maxCode(maxCode) {
+        _charsPerRow = _font->GetWidth() / _w;
+    }
+
+    void renderCharAlpha(int c, int x, int y, uint8_t color, uint8_t *fb, unsigned fbWidth, unsigned fbHeight) {
+        if (c < _minCode || c > _maxCode) return;
+        c -= _minCode;
+
+        auto bitmapX = (c % _charsPerRow) * _w;
+        auto bitmapY = (c / _charsPerRow) * _h;
+
+        for (auto charY = 0; charY < _h; charY++) {
+            if (y + charY < 0) continue;
+            if (y + charY >= fbHeight) break;
+            auto yOffset = (y + charY) * fbWidth;
+
+            for (auto charX = 0; charX < _w; charX++) {
+                if (x + charX < 0) continue;
+                if (x + charX >= fbWidth) break;
+
+                auto pv = _font->GetPixel(bitmapX + charX, bitmapY + charY);
+                if (pv & 0x80) continue;
+
+                fb[yOffset + x + charX] = color;
+            }
+        }
+    }
+
+    void renderChar(int c, int x, int y, uint8_t fgColor, uint8_t bgColor, uint8_t *fb, unsigned fbWidth, unsigned fbHeight) {
+        if (c < _minCode || c > _maxCode) return;
+        c -= _minCode;
+
+        auto bitmapX = (c % _charsPerRow) * _w;
+        auto bitmapY = (c / _charsPerRow) * _h;
+
+        for (auto charY = 0; charY < _h; charY++) {
+            if (y + charY < 0) continue;
+            if (y + charY >= fbHeight) break;
+            auto yOffset = (y + charY) * fbWidth;
+
+            for (auto charX = 0; charX < _w; charX++) {
+                if (x + charX < 0) continue;
+                if (x + charX >= fbWidth) break;
+
+                auto pv = _font->GetPixel(bitmapX + charX, bitmapY + charY) & 0x80 ? bgColor : fgColor;
+                fb[yOffset + x + charX] = pv;
+            }
+        }
+    }
+private:
+    Bitmap *_font;
+    unsigned _w, _h;
+    unsigned _minCode;
+    unsigned _maxCode;
+    unsigned _charsPerRow{0};
+};
+
+
+#endif //GAME_FONT_H

graphics/Rect.h

@@ -0,0 +1,45 @@
+#ifndef GAME_RECT_H
+#define GAME_RECT_H
+
+struct Rect {
+    int x1, y1, x2, y2;
+
+    void clamp(int minX, int minY, int maxX, int maxY) {
+        if (x1 < minX) x1 = minX;
+        if (x2 > maxX) x2 = maxX;
+        if (y1 < minY) y1 = minY;
+        if (y2 > maxY) y2 = maxY;
+    }
+
+    void sort() {
+        if (x1 > x2) {
+            auto x = x1;
+            x1 = x2;
+            x2 = x;
+        }
+        if (y1 > y2) {
+            auto y = y1;
+            y1 = y2;
+            y2 = y;
+        }
+    }
+
+    Rect &operator+=(const Rect &other) {
+        if (other.x1 < x1) x1 = other.x1;
+        if (other.x2 > x2) x2 = other.x2;
+        if (other.y1 < y1) y1 = other.y1;
+        if (other.y2 > y2) y2 = other.y2;
+
+        return *this;
+    }
+
+    [[nodiscard]] bool contains(int x, int y) const {
+        return x >= x1 && y >= y1 && x < x2 && y < y2;
+    }
+
+    [[nodiscard]] bool overlaps(const Rect &other) const {
+        return !(other.x1 > x2 || other.x2 < x1 || other.y1 > y2 || other.y2 < y1);
+    }
+};
+
+#endif //GAME_RECT_H

graphics/Sprite.h

@@ -0,0 +1,68 @@
+#ifndef GAME_SPRITE_H
+#define GAME_SPRITE_H
+#include "Bitmap.h"
+
+#define SPR_SUBPX_TO_PX(v) ((v) >= 0  ? ((v) >> 8) : -((-(v)) >> 8))
+#define SPR_PX_TO_SUBPX(v) ((v) >= 0  ? ((v) << 8) : -((-(v)) << 8))
+
+class Sprite {
+public:
+    virtual ~Sprite() = default;
+
+    virtual void Tick() = 0;
+
+    [[nodiscard]] virtual int GetWidth() const {
+        return _w;
+    }
+
+    [[nodiscard]] virtual int GetHeight() const {
+        return _h;
+    }
+
+    [[nodiscard]] int GetX() const {
+        return SPR_SUBPX_TO_PX(_sx);
+    }
+
+    [[nodiscard]] int GetY() const {
+        return SPR_SUBPX_TO_PX(_sy);
+    }
+
+    void SetX(int x) {
+        _sx = x >= 0  ? (x << 8) : -((-x) << 8);
+    }
+
+    void SetY(int y) {
+        _sy = y >= 0  ? (y << 8) : -((-y) << 8);
+    }
+
+    [[nodiscard]] Rect GetRect() const {
+        auto x = SPR_SUBPX_TO_PX(_sx), y = SPR_SUBPX_TO_PX(_sy);
+        return { x, y, x + _w, y + _h };
+    }
+
+    void SetPalette(uint8_t palette) { _palette = palette << 4; }
+
+    [[nodiscard]] uint8_t GetPalette() const { return _palette >> 4; }
+
+    [[nodiscard]] Bitmap *GetBitmap() const { return _bitmap; }
+
+    [[nodiscard]] unsigned GetYOffset() const { return _frame * _h; }
+
+    [[nodiscard]] bool isMirroredX() const { return _mirrorX; }
+
+    [[nodiscard]] bool isMirroredY() const { return _mirrorY; }
+
+protected:
+    Sprite() = default;
+
+    Bitmap *_bitmap{nullptr};
+    uint8_t _palette{0};
+    int _sx{0}, _sy{0};
+    int _w{0}, _h{0};
+    unsigned _frame{0};
+    bool _mirrorX{false};
+    bool _mirrorY{false};
+};
+
+
+#endif //GAME_SPRITE_H

install.bat

@@ -0,0 +1,2 @@
+mkdir C:\game\
+xcopy *.* C:\game\

main.cpp

@@ -0,0 +1,110 @@
+#include <cmath>
+#include <cstdio>
+#include <ctime>
+
+#ifdef BUILD_SDL
+#include <SDL_main.h>
+#endif
+
+#include "audio/AudioPlayer.h"
+#include "audio/Music.h"
+#include "system/Timer.h"
+#include "system/Video.h"
+#include "graphics/Bitmap.h"
+#include "graphics/Font.h"
+
+#include "scenes/Scene.h"
+#include "system/init.h"
+#include "system/Keyboard.h"
+#include "util/Gbm.h"
+#include "util/Log.h"
+
+volatile bool showFps = true;
+volatile bool running = true;
+
+int main(int argc, char *argv[]) {
+	System::init();
+
+	srand(time(nullptr));
+
+	DefaultLog.log("Loading music\n");
+	Music music("spiral.rad");
+	if (!music.isValid()) {
+		printf("Unable to load song\n");
+		return 1;
+	}
+
+	DefaultLog.log("Playing music\n");
+	audioPlayer.playMusic(music);
+
+	DefaultLog.log("Changing video mode\n");
+	video.Enter();
+
+	// Run scenes
+	auto fb = static_cast<uint8_t *>(video.GetFB());
+
+	unsigned fps{0};
+	unsigned frameCount{0};
+	uint32_t fpsTick{0};
+	char fpsDigits[4]{'0', '0', '0', 0};
+	auto fontBitmap = Gbm::loadFromFile("font1.gbm");
+	Font font(&fontBitmap, 7, 9, 32, 127);
+
+	keyboard.setKeyDownHandler([] (unsigned char key) {
+		DefaultLog.log("KeyDown %u (%s)\n", key, keyboard.getKeyName(key));
+	});
+	keyboard.setKeyUpHandler([] (unsigned char key) {
+		DefaultLog.log("KeyUp %u (%s)\n", key, keyboard.getKeyName(key));
+		switch (key) {
+			case KeyEscape:
+				running = false;
+				break;
+			case KeyF:
+				showFps = !showFps;
+				video.UpdateRect({0, 0, 21, 9 });
+				break;
+			default:
+				// Do nothing
+				break;
+		}
+	});
+	keyboard.setKeyRepeatHandler([](unsigned char key) {
+		DefaultLog.log("KeyRepeat %u (%s)\n", key, keyboard.getKeyName(key));
+	});
+
+	while (running) {
+		const auto scene = Scenes::getCurrentScene();
+
+		scene->run();
+
+		// Render fps
+		++frameCount;
+		auto ticks = timer.getTicks();
+		if (ticks > fpsTick + 50) {
+			fpsTick = ticks;
+			fps = frameCount;
+			frameCount = 0;
+			fpsDigits[0] = '0' + (fps / 100) % 10;
+			fpsDigits[1] = '0' + (fps / 10) % 10;
+			fpsDigits[2] = '0' + fps % 10;
+		}
+
+		if (showFps) {
+			font.renderChar(fpsDigits[0], 0, 0, 242, 0, fb, SCREEN_WIDTH, SCREEN_HEIGHT);
+			font.renderChar(fpsDigits[1], 7, 0, 242, 0, fb, SCREEN_WIDTH, SCREEN_HEIGHT);
+			font.renderChar(fpsDigits[2], 14, 0, 242, 0, fb, SCREEN_WIDTH, SCREEN_HEIGHT);
+
+			video.UpdateRect({0, 0, 21, 9 });
+		}
+
+		// Wait for vertical retrace and then copy render buffer to screen
+		video.WaitForVerticalSync();
+		video.Flip();
+	}
+
+	audioPlayer.stopMusic();
+
+	System::terminate();
+
+	return 0;
+}

scenes/GameScene.cpp

@@ -0,0 +1,281 @@
+#include "GameScene.h"
+
+#include <cstdio>
+#include <cstdlib>
+
+#include "../system/Keyboard.h"
+#include "../system/Timer.h"
+#include "../system/Video.h"
+#include "../util/Bmp.h"
+#include "../util/Gbm.h"
+#include "../util/Log.h"
+
+class TestSprite : public Sprite {
+public:
+	enum { Width = 20, Height = 16, Frames = 12 };
+
+	explicit TestSprite(Bitmap *image) {
+		_bitmap = image;
+		_w = Width;
+		_h = Height;
+		SetX(10 + rand() % (SCREEN_WIDTH - 20 - Width));
+		SetY(10 + rand() % (SCREEN_HEIGHT - 20 - Height));
+
+		int velXSign = ((rand() & 1) << 1) - 1;
+		int velYSign = ((rand() & 1) << 1) - 1;
+		_vx = (rand() % 128 + 64) * velXSign;
+		_vy = (rand() % 128 + 64) * velYSign;
+	}
+
+	void Tick() override {
+		if (++_ticks >= 15) {
+			_ticks = 0;
+			if (++_frame >= Frames) {
+				_frame = 0;
+			}
+		}
+
+		auto newX = _sx + _vx;
+		if (newX < 0) {
+			newX = -newX;
+			_vx = -_vx;
+		} else if (newX >= MaxX) {
+			auto d = newX - MaxX;
+			newX = MaxX - d - 1;
+			_vx = -_vx;
+		}
+		_mirrorX = (_vx < 0);
+
+		auto newY = _sy + _vy;
+		if (newY < 0) {
+			newY = -newY;
+			_vy = -_vy;
+		} else if (newY >= MaxY) {
+			auto d = newY - MaxY;
+			newY = MaxY - d - 1;
+			_vy = -_vy;
+		}
+
+		_sx = newX;
+		_sy = newY;
+	}
+
+protected:
+	int _vx{0}, _vy{0};
+	unsigned _ticks{0};
+	const int MaxX = (SCREEN_WIDTH - Width) << 8;
+	const int MaxY = (SCREEN_HEIGHT - Height) << 8;
+};
+
+class PlayerSprite : public Sprite {
+public:
+	enum { Width = 24, Height = 32, Frames = 4, Speed = 480 };
+
+	explicit PlayerSprite(Bitmap *image) {
+		_bitmap = image;
+		_w = Width;
+		_h = Height;
+		SetX(20);
+		SetY((SCREEN_HEIGHT - Height) / 2);
+	}
+
+	void Tick() override {
+		if (++_ticks >= 15) {
+			_ticks = 0;
+			if (++_animationStep >= Frames) {
+				_animationStep = 0;
+			}
+
+			_frame = _animationMap[_animationStep];
+		}
+
+		if (keyboard.keyState[KeyLeft]) {
+			_sx -= Speed;
+			if (_sx < 0) _sx = 0;
+		}
+		if (keyboard.keyState[KeyRight]) {
+			_sx += Speed;
+			if (_sx > MaxX) _sx = MaxX;
+		}
+		if (keyboard.keyState[KeyUp]) {
+			_sy -= Speed;
+			if (_sy < 0) _sy = 0;
+		}
+		if (keyboard.keyState[KeyDown]) {
+			_sy += Speed;
+			if (_sy > MaxY) _sy = MaxY;
+		}
+	}
+
+protected:
+	unsigned _ticks{0};
+	unsigned _animationStep = 0;
+	const int MaxX = (SCREEN_WIDTH - Width) << 8;
+	const int MaxY = (SCREEN_HEIGHT - Height) << 8;
+	const unsigned _animationMap[4] = {
+		0, 1, 2, 1
+	};
+};
+
+GameScene::GameScene() {
+
+}
+
+GameScene::~GameScene() {
+}
+
+void GameScene::run() {
+	if (_firstFrame) {
+		Rect bgRect{0, 0, SCREEN_WIDTH, SCREEN_HEIGHT};
+		for (auto y = 0; y < SCREEN_HEIGHT; y++) {
+			auto yOffset = y * SCREEN_WIDTH;
+			for (auto x = 0; x < SCREEN_WIDTH; x++) {
+				_fb[yOffset + x] = _bg.GetPixel(x, y);
+			}
+		}
+		video.UpdateRect(bgRect);
+		_firstFrame = false;
+	}
+
+	// Redraw background
+	for (auto &sprite : _sprites) {
+		clearSprite(sprite);
+	}
+	clearSprite(_playerSprite);
+
+	// Update and paint all sprites after update
+	for (auto &sprite : _sprites) {
+		sprite->Tick();
+		drawSprite(sprite);
+	}
+
+	_playerSprite->Tick();
+	drawSprite(_playerSprite);
+}
+
+void GameScene::enter() {
+	DefaultLog.log("Entering GameScene\n");
+	_fb = static_cast<uint8_t *>(video.GetFB());
+
+	_cow = Gbm::loadFromFile("cow.gbm");
+	_witch = Gbm::loadFromFile("witch.gbm");
+	_bg = Bmp::loadFromFile("bg.bmp");
+
+	_playerSprite = new PlayerSprite(&_witch);
+	_playerSprite->SetPalette(14);
+
+	for (auto &sprite : _sprites) {
+		sprite = new TestSprite(&_cow);
+		sprite->SetPalette(15);
+	}
+
+	// Load bg palette
+	for (auto i = 0u; i < 64; i++) {
+		video.SetPaletteEntry(i, _bg.GetPaletteEntry(i));
+	}
+
+	// Load sprite palette
+	for (auto i = 0u; i < 16; i++) {
+		video.SetPaletteEntry(i + 240, _cow.GetPaletteEntry(i));
+	}
+
+	// Load player sprite palette
+	for (auto i = 0u; i < 16; i++) {
+		video.SetPaletteEntry(i + 224, _witch.GetPaletteEntry(i));
+	}
+
+	_firstFrame = true;
+}
+
+void GameScene::exit() {
+	DefaultLog.log("Exiting GameScene\n");
+
+	for (auto &sprite : _sprites) {
+		delete sprite;
+	}
+
+	delete _playerSprite;
+
+	_cow.clear();
+	_bg.clear();
+	_witch.clear();
+}
+
+void GameScene::clearSprite(Sprite *sprite) {
+	auto rect = sprite->GetRect();
+	rect.clamp(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);
+
+	for (auto y = rect.y1; y < rect.y2; y++) {
+		auto yOffset = y * SCREEN_WIDTH;
+
+		for (auto x = rect.x1; x < rect.x2; x++) {
+			_fb[yOffset + x] = _bg.GetPixel(x, y);
+		}
+	}
+
+	video.UpdateRect(rect);
+}
+
+void GameScene::drawSprite(Sprite *sprite) {
+	auto rect = sprite->GetRect();
+	rect.clamp(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);
+
+	auto rx = rect.x1;
+	auto ry = rect.y1;
+	auto rx2 = rect.x2;
+	auto ry2 = rect.y2;
+
+	auto paletteOffset = sprite->GetPalette() << 4;
+	auto bitmap = sprite->GetBitmap();
+	auto syoff = sprite->GetYOffset();
+
+	if (sprite->isMirroredY()) {
+		for (auto y = ry; y < ry2; y++) {
+			auto yOffset = y * SCREEN_WIDTH;
+			auto offy = ry2 - y - 1;
+
+			if (sprite->isMirroredX()) {
+				for (auto x = rx; x < rx2; x++) {
+					auto offx = rx2 - x - 1;
+
+					auto pv = bitmap->GetPixel(offx, offy + syoff);
+
+					if (!(pv & 0x80)) _fb[yOffset + x] = (pv & 0x7f) + paletteOffset;
+				}
+			} else {
+				for (auto x = rx; x < rx2; x++) {
+					auto offx = x - rx;
+
+					auto pv = bitmap->GetPixel(offx, offy + syoff);
+
+					if (!(pv & 0x80)) _fb[yOffset + x] = (pv & 0x7f) + paletteOffset;
+				}
+			}
+		}
+	} else {
+		for (auto y = ry; y < ry2; y++) {
+			auto yOffset = y * SCREEN_WIDTH;
+			auto offy = y -ry;
+
+			if (sprite->isMirroredX()) {
+				for (auto x = rx; x < rx2; x++) {
+					auto offx = rx2 - x - 1;
+
+					auto pv = bitmap->GetPixel(offx, offy + syoff);
+
+					if (!(pv & 0x80)) _fb[yOffset + x] = (pv & 0x7f) + paletteOffset;
+				}
+			} else {
+				for (auto x = rx; x < rx2; x++) {
+					auto offx = x - rx;
+
+					auto pv = bitmap->GetPixel(offx, offy + syoff);
+
+					if (!(pv & 0x80)) _fb[yOffset + x] = (pv & 0x7f) + paletteOffset;
+				}
+			}
+		}
+	}
+
+	video.UpdateRect(rect);
+}

scenes/GameScene.h

@@ -0,0 +1,37 @@
+#ifndef GAME_GAMESCENE_H
+#define GAME_GAMESCENE_H
+
+#include <cstdint>
+
+#include "Scene.h"
+#include "../graphics/Bitmap.h"
+#include "../graphics/Sprite.h"
+
+#define MAX_OBJECTS 16
+
+class GameScene : public Scene {
+    public:
+        GameScene();
+        ~GameScene() override;
+
+        void run() override;
+
+        void enter() override;
+
+        void exit() override;
+    private:
+        uint8_t *_fb{nullptr};
+
+        Bitmap _bg;
+        Bitmap _cow;
+        Bitmap _witch;
+        Sprite *_playerSprite;
+        Sprite *_sprites[MAX_OBJECTS]{nullptr};
+        bool _firstFrame = true;
+
+        void clearSprite(Sprite *sprite);
+        void drawSprite(Sprite *sprite);
+};
+
+
+#endif //GAME_GAMESCENE_H

scenes/IntroScene.cpp

@@ -0,0 +1,11 @@
+#include "IntroScene.h"
+
+void IntroScene::run() {
+    Scenes::setScene(Scenes::MainMenuScene);
+}
+
+void IntroScene::enter() {
+}
+
+void IntroScene::exit() {
+}

scenes/IntroScene.h

@@ -0,0 +1,20 @@
+#ifndef GAME_INTROSCENE_H
+#define GAME_INTROSCENE_H
+
+#include "Scene.h"
+
+
+class IntroScene : public Scene {
+public:
+    IntroScene() = default;
+    ~IntroScene() override = default;
+
+    void run() override;
+
+    void enter() override;
+
+    void exit() override;
+};
+
+
+#endif //GAME_INTROSCENE_H

scenes/MainMenuScene.cpp

@@ -0,0 +1,11 @@
+#include "MainMenuScene.h"
+
+void MainMenuScene::run() {
+    Scenes::setScene(Scenes::GameScene);
+}
+
+void MainMenuScene::enter() {
+}
+
+void MainMenuScene::exit() {
+}

scenes/MainMenuScene.h

@@ -0,0 +1,20 @@
+#ifndef GAME_MAINMENUSCENE_H
+#define GAME_MAINMENUSCENE_H
+
+#include "Scene.h"
+
+
+class MainMenuScene : public Scene {
+public:
+    MainMenuScene() = default;
+    ~MainMenuScene() override = default;
+
+    void run() override;
+
+    void enter() override;
+
+    void exit() override;
+};
+
+
+#endif //GAME_MAINMENUSCENE_H

scenes/Scene.cpp

@@ -0,0 +1,19 @@
+#include "Scene.h"
+
+#include "GameScene.h"
+#include "IntroScene.h"
+#include "MainMenuScene.h"
+
+namespace Scenes {
+    static ::IntroScene introScene{};
+    static ::MainMenuScene mainMenuScene{};
+    static ::GameScene gameScene{};
+
+    SceneId currentSceneId = IntroScene;
+    Scene *sceneList[] = {
+        &introScene,
+        &mainMenuScene,
+        &gameScene
+    };
+}
+

scenes/Scene.h

@@ -0,0 +1,42 @@
+#ifndef GAME_SCENE_H
+#define GAME_SCENE_H
+
+#include "../graphics/Rect.h"
+
+class Scene {
+public:
+    virtual ~Scene() = default;
+    virtual void run() = 0;
+    virtual void enter() = 0;
+    virtual void exit() = 0;
+
+protected:
+    Scene() = default;
+};
+
+
+namespace Scenes {
+    enum SceneId {
+        IntroScene,
+        MainMenuScene,
+        GameScene,
+    };
+
+    extern SceneId currentSceneId;
+    extern Scene *sceneList[];
+
+    inline SceneId setScene(SceneId scene) {
+        auto previousSceneId = currentSceneId;
+        sceneList[currentSceneId]->exit();
+        currentSceneId = scene;
+        sceneList[currentSceneId]->enter();
+        return previousSceneId;
+    }
+
+    inline Scene *getCurrentScene() { return sceneList[currentSceneId]; }
+    inline SceneId getCurrentSceneId() { return currentSceneId; }
+
+}
+
+
+#endif //GAME_SCENE_H

system/Keyboard.h

@@ -0,0 +1,5 @@
+#ifdef BUILD_SDL
+#include "sdl/Keyboard.h"
+#else
+#include "dos/Keyboard.h"
+#endif

system/Opl.h

@@ -0,0 +1,9 @@
+#ifndef GAME_OPL_H
+#define GAME_OPL_H
+#include <cstdint>
+
+namespace Opl {
+    void write(uint16_t reg, uint8_t data);
+}
+
+#endif //GAME_OPL_H

system/Pic.h

@@ -0,0 +1,12 @@
+#ifndef GAME_PIC_H
+#define GAME_PIC_H
+
+#include "../util/Asm.h"
+
+namespace Pic {
+    static void clearInterrupt() {
+        outb(0x20, 0x20);
+    }
+}
+
+#endif //GAME_PIC_H

system/SoundBlaster.h

@@ -0,0 +1,36 @@
+#ifndef GAME_SOUNDBLASTER_H
+#define GAME_SOUNDBLASTER_H
+
+#ifdef BUILD_SDL
+#else
+#include <dpmi.h>
+#endif
+#include <cstdint>
+
+#define SB_BUFFER_SIZE 1024
+#define SB_BUFFERS 32
+#define SB_DMA_BUFFER_SIZE (SB_BUFFER_SIZE * 4)
+
+class SoundBlaster {
+public:
+    SoundBlaster();
+    ~SoundBlaster();
+
+private:
+    friend void soundblasterIsr();
+    void onInterrupt();
+
+#ifdef BUILD_SDL
+#else
+    _go32_dpmi_seginfo _dmaBuffer{};
+    uint8_t (*_buffers)[SB_BUFFER_SIZE]{};
+    uint8_t _dmaPage{0};
+    uint16_t _dmaOffset{0};
+    unsigned _nextBufferReadIndex{0};
+    unsigned _nextBufferWriteIndex{0};
+#endif
+};
+
+extern SoundBlaster soundblaster;
+
+#endif //GAME_SOUNDBLASTER_H

system/Timer.h

@@ -0,0 +1,49 @@
+#ifndef TICKS_H
+#define TICKS_H
+
+#include <cstdint>
+
+#ifdef BUILD_SDL
+#else
+#include <dpmi.h>
+#endif
+
+class Timer {
+public:
+	using Callback = void (*)();
+
+	Timer();
+
+	~Timer();
+
+	void setFrequency(uint16_t freq);
+
+	void setDivider(uint16_t div);
+
+	Callback setCallback(Callback);
+
+	[[nodiscard]] uint32_t getTicks() const;
+
+	[[nodiscard]] uint16_t getFrequency() const;
+
+private:
+	friend void timerISR();
+
+#ifdef BUILD_SDL
+#else
+	_go32_dpmi_seginfo _oldIsr{}, _newIsr{};
+#endif
+
+	uint32_t _ticks{0};
+	uint32_t _elapsed{0};
+	uint16_t _div{0};
+	uint16_t _freq{0};
+
+	void (*_callback)(){nullptr};
+
+	void update();
+};
+
+extern Timer timer;
+
+#endif

system/Video.h

@@ -0,0 +1,63 @@
+#ifndef VIDEO_H
+#define VIDEO_H
+
+#ifdef BUILD_SDL
+#include <SDL.h>
+#include <chrono>
+#else
+#include <cstdint>
+#endif
+
+#include "../graphics/Rect.h"
+
+#define SCREEN_WIDTH 320
+#define SCREEN_HEIGHT 200
+#define MAX_UPDATE_RECT_INDEX 255
+
+class Video {
+	public:
+		struct PaletteEntry {
+			uint8_t r{0}, g{0}, b{0};
+		};
+
+		Video();
+		~Video();
+
+		void Enter();
+		void Exit();
+
+		void SetPaletteEntry(uint8_t index, PaletteEntry entry);
+		PaletteEntry GetPaletteEntry(uint8_t index);
+
+		void SetPaletteEntry(uint8_t index, PaletteEntry *entry);
+		void GetPaletteEntry(uint8_t index, PaletteEntry *entry);
+
+		void *GetFB();
+
+		void WaitForVerticalSync();
+
+		void UpdateRect(const Rect &rect);
+		void Flip();
+	private:
+		uint8_t _oldMode{0};
+		PaletteEntry _oldPalette[256]{};
+#ifdef BUILD_SDL
+		SDL_Window *_window;
+		SDL_Surface *_windowSurface;
+		SDL_Surface *_fb;
+		PaletteEntry _palette[256]{};
+		std::chrono::steady_clock::time_point _lastUpdate{std::chrono::steady_clock::now()};
+#else
+		uint8_t *_fb{nullptr};
+#endif
+		uint8_t _renderBuffer[SCREEN_WIDTH*SCREEN_HEIGHT]{};
+		Rect _updatedRects[MAX_UPDATE_RECT_INDEX+1];
+		unsigned _updateRectIndex{0};
+
+		void SetMode(uint8_t mode);
+		uint8_t GetMode();
+};
+
+extern Video video;
+
+#endif

system/dos/Keyboard.cpp

@@ -0,0 +1,429 @@
+#include "../Keyboard.h"
+
+#include <go32.h>
+
+#include "../Pic.h"
+
+#define PIC
+#define KEYB_DATA 0x60
+
+Keyboard keyboard;
+
+static const char *keyNames[] = {
+    "<unknown:00>",
+    "KeyEscape", // = 0x01,
+    "Key1", // = 0x02,
+    "Key2", // = 0x03,
+    "Key3", // = 0x04,
+    "Key4", // = 0x05,
+    "Key5", // = 0x06,
+    "Key6", // = 0x07,
+    "Key7", // = 0x08,
+    "Key8", // = 0x09,
+    "Key9", // = 0x0a,
+    "Key0", // = 0x0b,
+    "KeyMinus", // = 0x0c,
+    "KeyEqual", // = 0x0d,
+    "KeyBackspace", // = 0x0e,
+    "KeyTab", // = 0x0f,
+    
+    "KeyQ", // = 0x10,
+    "KeyW", // = 0x11,
+    "KeyE", // = 0x12,
+    "KeyR", // = 0x13,
+    "KeyT", // = 0x14,
+    "KeyY", // = 0x15,
+    "KeyU", // = 0x16,
+    "KeyI", // = 0x17,
+    "KeyO", // = 0x18,
+    "KeyP", // = 0x19,
+    "KeyBracketLeft", // = 0x1a,
+    "KeyBracketRight", // = 0x1b,
+    "KeyEnter", // = 0x1c,
+    "KeyLeftCtrl", // = 0x1d,
+    "KeyA", // = 0x1e,
+    "KeyS", // = 0x1f,
+    
+    "KeyD", // = 0x20,
+    "KeyF", // = 0x21,
+    "KeyG", // = 0x22,
+    "KeyH", // = 0x23,
+    "KeyJ", // = 0x24,
+    "KeyK", // = 0x25,
+    "KeyL", // = 0x26,
+    "KeySemicolon", // = 0x27,
+    "KeyApostrophe", // = 0x28,
+    "KeyBacktick", // = 0x29,
+    "KeyLeftShift", // = 0x2a,
+    "KeyBackslash", // = 0x2b,
+    "KeyZ", // = 0x2c,
+    "KeyX", // = 0x2d,
+    "KeyC", // = 0x2e,
+    "KeyV", // = 0x2f,
+    
+    "KeyB", // = 0x30,
+    "KeyN", // = 0x31,
+    "KeyM", // = 0x32,
+    "KeyComma", // = 0x33,
+    "KeyPeriod", // = 0x34,
+    "KeySlash", // = 0x35,
+    "KeyRightShift", // = 0x36,
+    "KeyKeypadMultiply", // = 0x37,
+    "KeyLeftAlt", // = 0x38,
+    "KeySpace", // = 0x39,
+    "KeyCapsLock", // = 0x3a,
+    "KeyF1", // = 0x3b,
+    "KeyF2", // = 0x3c,
+    "KeyF3", // = 0x3d,
+    "KeyF4", // = 0x3e,
+    "KeyF5", // = 0x3f,
+    
+    "KeyF6", // = 0x40,
+    "KeyF7", // = 0x41,
+    "KeyF8", // = 0x42,
+    "KeyF9", // = 0x43,
+    "KeyF10", // = 0x44,
+    "KeyNumLock", // = 0x45,
+    "KeyScrollLock", // = 0x46,
+    "KeyKeypad7", // = 0x47,
+    "KeyKeypad8", // = 0x48,
+    "KeyKeypad9", // = 0x49,
+    "KeyKeypadMinus", // = 0x4a,
+    "KeyKeypad4", // = 0x4b,
+    "KeyKeypad5", // = 0x4c,
+    "KeyKeypad6", // = 0x4d,
+    "KeyKeypadPlus", // = 0x4e,
+    "KeyKeypad1", // = 0x4f,
+    
+    "KeyKeypad2", // = 0x50,
+    "KeyKeypad3", // = 0x51,
+    "KeyKeypad0", // = 0x52,
+    "KeyKeypadPeriod", // = 0x53,
+    "<unknown:54>",
+    "<unknown:55>",
+    "<unknown:56>",
+    "KeyF11", // = 0x57,
+    "KeyF12", // = 0x58,
+    "<unknown:59>",
+    "<unknown:5a>",
+    "<unknown:5b>",
+    "<unknown:5c>",
+    "<unknown:5d>",
+    "<unknown:5e>",
+    "<unknown:5f>",
+
+    "<unknown:60>",
+    "<unknown:61>",
+    "<unknown:62>",
+    "<unknown:63>",
+    "<unknown:64>",
+    "<unknown:65>",
+    "<unknown:66>",
+    "<unknown:67>",
+    "<unknown:68>",
+    "<unknown:69>",
+    "<unknown:6a>",
+    "<unknown:6b>",
+    "<unknown:6c>",
+    "<unknown:6d>",
+    "<unknown:6e>",
+    "<unknown:6f>",
+
+    "<unknown:70>",
+    "<unknown:71>",
+    "<unknown:72>",
+    "<unknown:73>",
+    "<unknown:74>",
+    "<unknown:75>",
+    "<unknown:76>",
+    "<unknown:77>",
+    "<unknown:78>",
+    "<unknown:79>",
+    "<unknown:7a>",
+    "<unknown:7b>",
+    "<unknown:7c>",
+    "<unknown:7d>",
+    "<unknown:7e>",
+    "<unknown:7f>",
+
+    "<unknown:80>",
+    "<unknown:81>",
+    "<unknown:82>",
+    "<unknown:83>",
+    "<unknown:84>",
+    "<unknown:85>",
+    "<unknown:86>",
+    "<unknown:87>",
+    "<unknown:88>",
+    "<unknown:89>",
+    "<unknown:8a>",
+    "<unknown:8b>",
+    "<unknown:8c>",
+    "<unknown:8d>",
+    "<unknown:8e>",
+    "<unknown:8f>",
+
+    "KeyMediaPrev", // = 0x90,
+    "<unknown:91>",
+    "<unknown:92>",
+    "<unknown:93>",
+    "<unknown:94>",
+    "<unknown:95>",
+    "<unknown:96>",
+    "<unknown:97>",
+    "<unknown:98>",
+    "KeyMediaNext", // = 0x99,
+    "<unknown:9a>",
+    "<unknown:9b>",
+    "KeyKeypadEnter", // = 0x9c,
+    "KeyRightControl", // = 0x9d,
+    "<unknown:9e>",
+    "<unknown:9f>",
+
+    "KeyMediaMute", // = 0xa0,
+    "KeyMediaCalculator", // = 0xa1,
+    "KeyMediaPlay", // = 0xa2,
+    "<unknown:a3>",
+    "KeyMediaStop", // = 0xa4,
+    "<unknown:a5>",
+    "<unknown:a6>",
+    "<unknown:a7>",
+    "<unknown:a8>",
+    "<unknown:a9>",
+    "<unknown:aa>",
+    "<unknown:ab>",
+    "<unknown:ac>",
+    "<unknown:ad>",
+    "KeyMediaVolumeDown", // = 0xae,
+    "<unknown:af>",
+
+    "KeyMediaVolumeUp", // = 0xb0,
+    "<unknown:b1>",
+    "KeyMediaWww", // = 0xb2,
+    "<unknown:b3>",
+    "<unknown:b4>",
+    "KeyKeypadDivide", // = 0xb5,
+    "<unknown:b6>",
+    "<unknown:b7>",
+    "KeyRightAlt", // = 0xb8,
+    "<unknown:b9>",
+    "<unknown:ba>",
+    "<unknown:bb>",
+    "<unknown:bc>",
+    "<unknown:bd>",
+    "<unknown:be>",
+    "<unknown:bf>",
+
+    "<unknown:c0>",
+    "<unknown:c1>",
+    "<unknown:c2>",
+    "<unknown:c3>",
+    "<unknown:c4>",
+    "<unknown:c5>",
+    "<unknown:c6>",
+    "KeyHome", // = 0xc7,
+    "KeyUp", // = 0xc8,
+    "KeyPageUp", // = 0xc9,
+    "<unknown:ca>",
+    "KeyLeft", // = 0xcb,
+    "<unknown:cc>",
+    "KeyRight", // = 0xcd,
+    "<unknown:ce>",
+    "KeyEnd", // = 0xcf,
+
+    "KeyDown", // = 0xd0,
+    "KeyPageDown", // = 0xd1,
+    "KeyInsert", // = 0xd2,
+    "KeyDelete", // = 0xd3,
+    "<unknown:d4>",
+    "<unknown:d5>",
+    "<unknown:d6>",
+    "<unknown:d7>",
+    "<unknown:d8>",
+    "<unknown:d9>",
+    "<unknown:da>",
+    "KeyLeftGui", // = 0xdb,
+    "KeyRightGui", // = 0xdc,
+    "KeyApps", // = 0xdd,
+    "KeyAcpiPower", // = 0xde,
+    "KeyAcpiSleep", // = 0xdf,
+
+    "<unknown:e0>",
+    "<unknown:e1>",
+    "<unknown:e2>",
+    "KeyAcpiWake", // = 0xe3,
+    "<unknown:e4>",
+    "KeyMediaWwwSearch", // = 0xe5,
+    "KeyMediaWwwFavorites", // = 0xe6,
+    "KeyMediaWwwRefresh", // = 0xe7,
+    "KeyMediaWwwStop", // = 0xe8,
+    "KeyMediaWwwForward", // = 0xe9,
+    "KeyMediaWwwBack", // = 0xea,
+    "KeyMediaMyComputer", // = 0xeb,
+    "KeyMediaEmail", // = 0xec,
+    "KeyMediaSelect", // = 0xed,
+    "<unknown:ee>",
+    "<unknown:ef>",
+
+    "<unknown:f0>",
+    "<unknown:f1>",
+    "<unknown:f2>",
+    "<unknown:f3>",
+    "<unknown:f4>",
+    "<unknown:f5>",
+    "<unknown:f6>",
+    "<unknown:f7>",
+    "<unknown:f8>",
+    "<unknown:f9>",
+    "<unknown:fa>",
+    "<unknown:fb>",
+    "<unknown:fc>",
+    "<unknown:fd>",
+    "KeyPrint", // = 0xfe,
+    "KeyPause", // = 0xff,
+};
+
+void keyboardIsr() {
+    keyboard.Isr();
+}
+
+Keyboard::Keyboard() {
+    _go32_dpmi_get_protected_mode_interrupt_vector(9, &_oldIsr);
+
+    _newIsr.pm_offset = (int)keyboardIsr;
+    _newIsr.pm_selector = _go32_my_cs();
+    _go32_dpmi_allocate_iret_wrapper(&_newIsr);
+    _go32_dpmi_set_protected_mode_interrupt_vector(9, &_newIsr);
+}
+
+Keyboard::~Keyboard() {
+    _go32_dpmi_set_protected_mode_interrupt_vector(9, &_oldIsr);
+    _go32_dpmi_free_iret_wrapper(&_newIsr);
+}
+
+Keyboard::KeyHandleFunction Keyboard::setKeyUpHandler(KeyHandleFunction handler) {
+    auto oldHandler = _keyUpHandler;
+    _keyUpHandler = handler;
+    return oldHandler;
+}
+
+Keyboard::KeyHandleFunction Keyboard::setKeyDownHandler(KeyHandleFunction handler) {
+    auto oldHandler = _keyDownHandler;
+    _keyDownHandler = handler;
+    return oldHandler;
+}
+
+Keyboard::KeyHandleFunction Keyboard::setKeyRepeatHandler(KeyHandleFunction handler) {
+    auto oldHandler = _keyRepeatHandler;
+    _keyRepeatHandler = handler;
+    return oldHandler;
+}
+
+const char *Keyboard::getKeyName(unsigned char keyCode) {
+    return keyNames[keyCode];
+}
+
+void Keyboard::Isr() {
+    auto code = inb(KEYB_DATA);
+    switch (_state) {
+        case Start:
+            if (code == 0xe0) {
+                _state = Extended;
+                break;
+            }
+            if (code == 0xe1) {
+                _state = PauseBegin;
+                break;
+            }
+            if (code & 0x80) {
+                _state = Start;
+                keyUp(code & 0x7f);
+            } else {
+                _state = Start;
+                keyDown(code & 0x7f);
+            }
+            break;
+        case Extended:
+            if (code == 0x2a) {
+                _state = PrintPressed1;
+                break;
+            }
+            if (code == 0xb7) {
+                _state = PrintReleased1;
+                break;
+            }
+            if (code & 0x80) {
+                _state = Start;
+                keyUp(0x80 + (code & 0x7f));
+            } else {
+                _state = Start;
+                keyDown(0x80 + code);
+            }
+            break;
+        case PauseBegin:
+            if (code == 0x1d) {
+                _state = PausePressed1;
+                break;
+            }
+            if (code == 0x9d) {
+                _state = PauseReleased1;
+                break;
+            }
+            _state = Start;
+            break;
+        case PausePressed1:
+            if (code == 45) {
+                keyDown(KeyPause);
+            }
+            _state = Start;
+            break;
+        case PauseReleased1:
+            if (code == 0xc5) {
+                keyUp(KeyPause);
+            }
+            _state = Start;
+            break;
+        case PrintPressed1:
+            if (code == 0xe0) {
+                _state = PrintPressed2;
+                break;
+            }
+            _state = Start;
+            break;
+        case PrintPressed2:
+            if (code == 0x37) {
+                keyDown(KeyPrint);
+            }
+            _state = Start;
+            break;
+        case PrintReleased1:
+            if (code == 0xe0) {
+                _state = PrintReleased2;
+                break;
+            }
+            _state = Start;
+            break;
+        case PrintReleased2:
+            if (code == 0xaa) {
+                keyUp(KeyPrint);
+            }
+            _state = Start;
+            break;
+    }
+
+    Pic::clearInterrupt();
+}
+
+void Keyboard::keyDown(unsigned char c) {
+    if (keyState[c]) {
+        if (_keyRepeatHandler) _keyRepeatHandler(c);
+    } else {
+        keyState[c] = true;
+        if (_keyDownHandler) _keyDownHandler(c);
+    }
+}
+
+void Keyboard::keyUp(unsigned char c) {
+    keyState[c] = false;
+    if (_keyUpHandler) _keyUpHandler(c);
+}

system/dos/Keyboard.h

@@ -0,0 +1,182 @@
+#ifndef GAME_KEYBOARD_H
+#define GAME_KEYBOARD_H
+
+#ifdef BUILD_SDL
+#else
+#include <dpmi.h>
+#endif
+
+#define KEY_MAX 256
+
+enum {
+    KeyEscape = 0x01,
+    Key1 = 0x02,
+    Key2 = 0x03,
+    Key3 = 0x04,
+    Key4 = 0x05,
+    Key5 = 0x06,
+    Key6 = 0x07,
+    Key7 = 0x08,
+    Key8 = 0x09,
+    Key9 = 0x0a,
+    Key0 = 0x0b,
+    KeyMinus = 0x0c,
+    KeyEqual = 0x0d,
+    KeyBackspace = 0x0e,
+    KeyTab = 0x0f,
+    KeyQ = 0x10,
+    KeyW = 0x11,
+    KeyE = 0x12,
+    KeyR = 0x13,
+    KeyT = 0x14,
+    KeyY = 0x15,
+    KeyU = 0x16,
+    KeyI = 0x17,
+    KeyO = 0x18,
+    KeyP = 0x19,
+    KeyBracketLeft = 0x1a,
+    KeyBracketRight = 0x1b,
+    KeyEnter = 0x1c,
+    KeyLeftCtrl = 0x1d,
+    KeyA = 0x1e,
+    KeyS = 0x1f,
+    KeyD = 0x20,
+    KeyF = 0x21,
+    KeyG = 0x22,
+    KeyH = 0x23,
+    KeyJ = 0x24,
+    KeyK = 0x25,
+    KeyL = 0x26,
+    KeySemicolon = 0x27,
+    KeyApostrophe = 0x28,
+    KeyBacktick = 0x29,
+    KeyLeftShift = 0x2a,
+    KeyBackslash = 0x2b,
+    KeyZ = 0x2c,
+    KeyX = 0x2d,
+    KeyC = 0x2e,
+    KeyV = 0x2f,
+    KeyB = 0x30,
+    KeyN = 0x31,
+    KeyM = 0x32,
+    KeyComma = 0x33,
+    KeyPeriod = 0x34,
+    KeySlash = 0x35,
+    KeyRightShift = 0x36,
+    KeyKeypadMultiply = 0x37,
+    KeyLeftAlt = 0x38,
+    KeySpace = 0x39,
+    KeyCapsLock = 0x3a,
+    KeyF1 = 0x3b,
+    KeyF2 = 0x3c,
+    KeyF3 = 0x3d,
+    KeyF4 = 0x3e,
+    KeyF5 = 0x3f,
+    KeyF6 = 0x40,
+    KeyF7 = 0x41,
+    KeyF8 = 0x42,
+    KeyF9 = 0x43,
+    KeyF10 = 0x44,
+    KeyNumLock = 0x45,
+    KeyScrollLock = 0x46,
+    KeyKeypad7 = 0x47,
+    KeyKeypad8 = 0x48,
+    KeyKeypad9 = 0x49,
+    KeyKeypadMinus = 0x4a,
+    KeyKeypad4 = 0x4b,
+    KeyKeypad5 = 0x4c,
+    KeyKeypad6 = 0x4d,
+    KeyKeypadPlus = 0x4e,
+    KeyKeypad1 = 0x4f,
+    KeyKeypad2 = 0x50,
+    KeyKeypad3 = 0x51,
+    KeyKeypad0 = 0x52,
+    KeyKeypadPeriod = 0x53,
+    KeyF11 = 0x57,
+    KeyF12 = 0x58,
+    KeyMediaPrev = 0x90,
+    KeyMediaNext = 0x99,
+    KeyKeypadEnter = 0x9c,
+    KeyRightControl = 0x9d,
+    KeyMediaMute = 0xa0,
+    KeyMediaCalculator = 0xa1,
+    KeyMediaPlay = 0xa2,
+    KeyMediaStop = 0xa4,
+    KeyMediaVolumeDown = 0xae,
+    KeyMediaVolumeUp = 0xb0,
+    KeyMediaWww = 0xb2,
+    KeyKeypadDivide = 0xb5,
+    KeyRightAlt = 0xb8,
+    KeyHome = 0xc7,
+    KeyUp = 0xc8,
+    KeyPageUp = 0xc9,
+    KeyLeft = 0xcb,
+    KeyRight = 0xcd,
+    KeyEnd = 0xcf,
+    KeyDown = 0xd0,
+    KeyPageDown = 0xd1,
+    KeyInsert = 0xd2,
+    KeyDelete = 0xd3,
+    KeyLeftGui = 0xdb,
+    KeyRightGui = 0xdc,
+    KeyApps = 0xdd,
+    KeyAcpiPower = 0xde,
+    KeyAcpiSleep = 0xdf,
+    KeyAcpiWake = 0xe3,
+    KeyMediaWwwSearch = 0xe5,
+    KeyMediaWwwFavorites = 0xe6,
+    KeyMediaWwwRefresh = 0xe7,
+    KeyMediaWwwStop = 0xe8,
+    KeyMediaWwwForward = 0xe9,
+    KeyMediaWwwBack = 0xea,
+    KeyMediaMyComputer = 0xeb,
+    KeyMediaEmail = 0xec,
+    KeyMediaSelect = 0xed,
+    KeyPrint = 0xfe,
+    KeyPause = 0xff,
+};
+
+class Keyboard {
+public:
+    using KeyHandleFunction = void (*)(unsigned char);
+
+    Keyboard();
+    ~Keyboard();
+
+    KeyHandleFunction setKeyUpHandler(KeyHandleFunction handler);
+    KeyHandleFunction setKeyDownHandler(KeyHandleFunction handler);
+    KeyHandleFunction setKeyRepeatHandler(KeyHandleFunction handler);
+
+    bool keyState[KEY_MAX]{};
+
+    const char *getKeyName(unsigned char keyCode);
+private:
+    friend void keyboardIsr();
+    void Isr();
+    enum State {
+        Start,
+        Extended,
+        PauseBegin,
+        PausePressed1,
+        PauseReleased1,
+        PrintPressed1,
+        PrintPressed2,
+        PrintReleased1,
+        PrintReleased2,
+    };
+    State _state;
+    KeyHandleFunction _keyDownHandler{nullptr}, _keyUpHandler{nullptr}, _keyRepeatHandler{nullptr};
+
+    void keyDown(unsigned char c);
+
+    void keyUp(unsigned char c);
+
+#ifdef BUILD_SDL
+#else
+    _go32_dpmi_seginfo _oldIsr, _newIsr;
+#endif
+};
+
+extern Keyboard keyboard;
+
+#endif //GAME_KEYBOARD_H

system/dos/Opl.cpp

@@ -0,0 +1,16 @@
+#include "../Opl.h"
+#include "../../util/Asm.h"
+
+#define OPL_REG 0x388
+
+namespace Opl {
+    void write(uint16_t reg, uint8_t data) {
+        if (reg >= 0x100) {
+            outb(OPL_REG + 2, reg & 0xff);
+            outb(OPL_REG + 3, data);
+        } else {
+            outb(OPL_REG, reg);
+            outb(OPL_REG + 1, data);
+        }
+    }
+}

system/dos/SoundBlaster.cpp

@@ -0,0 +1,47 @@
+#include "../SoundBlaster.h"
+
+#include <go32.h>
+
+SoundBlaster soundblaster;
+
+void soundblasterIsr() {
+    soundblaster.onInterrupt();
+}
+
+SoundBlaster::SoundBlaster() {
+    // Allocate twice the amount needed and select one half depending on whether it crosses a 64k boundary
+    _dmaBuffer.size = (SB_DMA_BUFFER_SIZE + 15) >> (4-1);
+    _go32_dpmi_allocate_dos_memory(&_dmaBuffer);
+
+    auto physFirst = (_dmaBuffer.rm_segment << 4) + _dmaBuffer.rm_offset;
+    auto physSecond = physFirst + SB_DMA_BUFFER_SIZE;
+    auto pageFirst = physFirst >> 16;
+    auto pageSecond = physSecond >> 16;
+
+    if (pageFirst == pageSecond) {
+        // Use first half
+        _buffers = reinterpret_cast<decltype(_buffers)>(physFirst);
+        _dmaPage = pageFirst;
+        _dmaOffset = physFirst & 0xFFFF;
+    } else {
+        // Use second half
+        _buffers = reinterpret_cast<decltype(_buffers)>(physSecond);
+        _dmaPage = pageSecond;
+        _dmaOffset = physSecond & 0xFFFF;
+    }
+}
+
+SoundBlaster::~SoundBlaster() {
+    _go32_dpmi_free_dos_memory(&_dmaBuffer);
+}
+
+void SoundBlaster::onInterrupt() {
+    // No data available - should not happen, but let's force generate a block
+    if (_nextBufferReadIndex == _nextBufferWriteIndex) {
+        generateSamples();
+    }
+
+    dosmemput(_buffers, SB_BUFFER_SIZE, (_dmaBuffer.rm_segment << 4) + _nextBufferReadIndex * SB_BUFFER_SIZE);
+    _nextBufferReadIndex = (_nextBufferReadIndex + 1) & 3;
+}
+

system/dos/Timer.cpp

@@ -0,0 +1,97 @@
+#include <go32.h>
+
+#include "../Timer.h"
+
+#include "../Pic.h"
+#include "../../util/Asm.h"
+
+#define PIT_FREQ 1193181
+#define PIT_MODE_CH0 0x00
+#define PIT_MODE_CH1 0x40
+#define PIT_MODE_CH2 0x80
+#define PIT_MODE_ACCESS_LO 0x10
+#define PIT_MODE_ACCESS_HI 0x20
+#define PIT_MODE_ACCESS_LOHI 0x30
+#define PIT_MODE_M0 0x00
+#define PIT_MODE_M1 0x02
+#define PIT_MODE_M2 0x04
+#define PIT_MODE_M3 0x06
+#define PIT_MODE_M4 0x08
+#define PIT_MODE_M5 0x0a
+#define PIT_MODE_BIN 0x00
+#define PIT_MODE_BCD 0x01
+
+#define PIT_REG_CH0 0x40
+#define PIT_REG_CH1 0x41
+#define PIT_REG_CH2 0x42
+#define PIT_REG_MODE 0x43
+
+Timer timer;
+
+void timerISR() {
+	timer.update();
+}
+
+Timer::Timer() {
+	_go32_dpmi_get_protected_mode_interrupt_vector(8, &_oldIsr);
+	
+	_newIsr.pm_offset = reinterpret_cast<int>(timerISR);
+    _newIsr.pm_selector = _go32_my_cs();
+    _go32_dpmi_allocate_iret_wrapper(&_newIsr);
+	_go32_dpmi_set_protected_mode_interrupt_vector(8, &_newIsr);
+}
+
+Timer::~Timer() {
+	setDivider(65535);
+	_go32_dpmi_set_protected_mode_interrupt_vector(8, &_oldIsr);
+	_go32_dpmi_free_iret_wrapper(&_newIsr);
+}
+
+void Timer::update() {
+	_ticks++;
+	
+	if (_callback) _callback();
+	
+	_elapsed += _div;
+	if (_elapsed >= 65535) {
+		_elapsed -= 65535;
+		// TODO call old isr
+		// Documentation is kind of nonexistant so we will not call the handler for now
+		Pic::clearInterrupt();
+	} else {
+		Pic::clearInterrupt();
+	}
+}
+
+uint32_t Timer::getTicks() const {
+	return _ticks;
+}
+
+uint16_t Timer::getFrequency() const {
+	return _freq;
+}
+
+void Timer::setFrequency(uint16_t freq) {
+	_freq = freq;
+	setDivider(PIT_FREQ / freq);
+}
+
+void Timer::setDivider(uint16_t div) {
+	auto wasEnabled = interruptsEnabled();
+	disableInterrupts();
+	
+	_div = div;
+	
+	// Update PIT frequency
+    outb(PIT_REG_MODE, PIT_MODE_CH0|PIT_MODE_ACCESS_LOHI|PIT_MODE_M2|PIT_MODE_BIN);
+    outb(PIT_REG_CH0, _div & 0xff);
+    outb(PIT_REG_CH0, (_div >> 8) & 0xff);
+	
+	if (wasEnabled) enableInterrupts();
+}
+
+Timer::Callback Timer::setCallback(Timer::Callback callback) {
+	auto oldCallback = _callback;
+	_callback = callback;
+	return oldCallback;
+}

system/dos/Video.cpp

@@ -0,0 +1,135 @@
+#include <dos.h>
+#include <sys/nearptr.h>
+
+#include "../Video.h"
+#include "../../util/Asm.h"
+#include "../../util/Log.h"
+
+#define VGA_DAC_ADDR_RD 0x3c7
+#define VGA_DAC_ADDR_WR 0x3c8
+#define VGA_DAC_DATA 0x3c9
+#define VGA_EXT_INPUT_STATUS 0x3da
+#define VGA_EXT_INPUT_STATUS_VRETRACE 8
+
+Video video;
+
+Video::Video() {
+	__djgpp_nearptr_enable();
+
+	// Store current video mode
+	_oldMode = GetMode();
+
+	// Store current palette
+	for (auto i = 0; i < 256; i++) {
+		GetPaletteEntry(i, &_oldPalette[i]);
+	}
+}
+
+Video::~Video() {
+	Exit();
+}
+
+void Video::Enter() {
+	SetMode(0x13);
+}
+
+void Video::Exit() {
+	// Restore old palette
+	for (auto i = 0; i < 256; i++) {
+		SetPaletteEntry(i, &_oldPalette[i]);
+	}
+
+	// Restore old video mode
+	SetMode(_oldMode);
+}
+
+void Video::SetMode(uint8_t mode) {
+	union REGS regs;
+	regs.h.ah = 0x00;
+	regs.h.al = mode;
+	int86(0x10, &regs, &regs);
+
+	//__djgpp_nearptr_enable();
+	switch (mode) {
+		default:
+		case 0x13:
+			_fb = (uint8_t *)(0xA0000 + __djgpp_conventional_base);
+
+	}
+}
+
+uint8_t Video::GetMode() {
+	union REGS regs;
+	regs.h.ah = 0x0f;
+	regs.h.al = 0;
+	int86(0x10, &regs, &regs);
+
+	return regs.h.al;
+}
+
+void Video::SetPaletteEntry(uint8_t index, PaletteEntry entry) {
+	SetPaletteEntry(index, &entry);
+}
+
+Video::PaletteEntry Video::GetPaletteEntry(uint8_t index) {
+	PaletteEntry entry;
+	GetPaletteEntry(index, &entry);
+	return entry;
+}
+
+void Video::SetPaletteEntry(uint8_t index, PaletteEntry *entry) {
+	outb(VGA_DAC_ADDR_WR, index);
+	outb(VGA_DAC_DATA, entry->r >> 2);
+	outb(VGA_DAC_DATA, entry->g >> 2);
+	outb(VGA_DAC_DATA, entry->b >> 2);
+}
+
+void Video::GetPaletteEntry(uint8_t index, PaletteEntry *entry) {
+	outb(VGA_DAC_ADDR_RD, index);
+	entry->r = inb(VGA_DAC_DATA);
+	entry->g = inb(VGA_DAC_DATA);
+	entry->b = inb(VGA_DAC_DATA);
+}
+
+void *Video::GetFB() {
+	return _renderBuffer;
+}
+
+void Video::WaitForVerticalSync() {
+	auto state = inb(VGA_EXT_INPUT_STATUS) & VGA_EXT_INPUT_STATUS_VRETRACE;
+	if (!state) {
+		// We started before a retrace, so wait until it begins
+		while (!(inb(VGA_EXT_INPUT_STATUS) & VGA_EXT_INPUT_STATUS_VRETRACE)) {}
+	}
+	// Wait until it ends
+	while (inb(VGA_EXT_INPUT_STATUS) & VGA_EXT_INPUT_STATUS_VRETRACE);
+}
+
+void Video::UpdateRect(const Rect &rect) {
+	// Merge rect if it overlaps with an existing rect
+	for (auto i = 0; i < _updateRectIndex; i++) {
+		auto &r = _updatedRects[i];
+		if (r.overlaps(rect)) {
+			r += rect;
+			return;
+		}
+	}
+
+	// Add a new rect to the list
+	_updatedRects[_updateRectIndex++] = rect;
+}
+
+void Video::Flip() {
+	for (auto i = 0; i <= MAX_UPDATE_RECT_INDEX; i++) {
+		auto &rect = _updatedRects[i];
+		for (auto y = rect.y1; y <= rect.y2; y++) {
+			auto yOffset = y * SCREEN_WIDTH;
+
+			for (auto x = rect.x1; x <= rect.x2; x++) {
+				_fb[yOffset + x] = _renderBuffer[yOffset + x];
+			}
+		}
+	}
+
+	_updateRectIndex = 0;
+}

system/dos/init.cpp

@@ -0,0 +1,12 @@
+#include "../init.h"
+
+namespace System {
+    void init() {
+
+    }
+
+    void terminate() {
+
+    }
+}
+

system/init.h

@@ -0,0 +1,9 @@
+#ifndef GAME_INIT_H
+#define GAME_INIT_H
+
+namespace System {
+    void init();
+    void terminate();
+}
+
+#endif //GAME_INIT_H

system/sdl/Events.cpp

@@ -0,0 +1,25 @@
+#include <SDL.h>
+#include "Events.h"
+
+#include "Keyboard.h"
+
+Events events;
+
+void Events::poll() {
+    SDL_Event event;
+    while (SDL_PollEvent(&event)) {
+        // TODO handle events
+        switch (event.type) {
+            case SDL_QUIT:
+                // TODO
+                exit(0);
+                break;
+            case SDL_KEYDOWN:
+                keyboard.keyDown(event.key.keysym.sym);
+                break;
+            case SDL_KEYUP:
+                keyboard.keyUp(event.key.keysym.sym);
+                break;
+        }
+    }
+}

system/sdl/Events.h

@@ -0,0 +1,14 @@
+#ifndef GAME_EVENTS_H
+#define GAME_EVENTS_H
+
+class Events {
+public:
+    Events() = default;
+    ~Events() = default;
+
+    void poll();
+};
+
+extern Events events;
+
+#endif //GAME_EVENTS_H

system/sdl/Keyboard.cpp

@@ -0,0 +1,821 @@
+#include <SDL.h>
+#include "../Keyboard.h"
+
+Keyboard keyboard;
+
+// TODO map unknown key codes
+uint8_t mapSdlKeycode(SDL_Keycode keyCode) {
+    switch (keyCode) {
+        case SDLK_UNKNOWN:
+            return KeyUnknown;
+        case SDLK_RETURN:
+            return KeyUnknown;
+        case SDLK_ESCAPE:
+            return KeyEscape;
+        case SDLK_BACKSPACE:
+            return KeyBackspace;            
+        case SDLK_TAB:
+            return KeyTab;
+        case SDLK_SPACE:
+            return KeySpace;
+        case SDLK_EXCLAIM:
+            return KeyUnknown;
+        case SDLK_QUOTEDBL:
+            return KeyUnknown;
+        case SDLK_HASH:
+            return KeyUnknown;
+        case SDLK_PERCENT:
+            return KeyUnknown;
+        case SDLK_DOLLAR:
+            return KeyUnknown;
+        case SDLK_AMPERSAND:
+            return KeyUnknown;
+        case SDLK_QUOTE:
+            return KeyUnknown;
+        case SDLK_LEFTPAREN:
+            return KeyUnknown;
+        case SDLK_RIGHTPAREN:
+            return KeyUnknown;
+        case SDLK_ASTERISK:
+            return KeyUnknown;
+        case SDLK_PLUS:
+            return KeyUnknown;
+        case SDLK_COMMA:
+            return KeyUnknown;
+        case SDLK_MINUS:
+            return KeyUnknown;
+        case SDLK_PERIOD:
+            return KeyUnknown;
+        case SDLK_SLASH:
+            return KeyUnknown;
+        case SDLK_0:
+            return Key0;
+        case SDLK_1:
+            return Key1;
+        case SDLK_2:
+            return Key2;
+        case SDLK_3:
+            return Key3;
+        case SDLK_4:
+            return Key4;
+        case SDLK_5:
+            return Key5;
+        case SDLK_6:
+            return Key6;
+        case SDLK_7:
+            return Key7;
+        case SDLK_8:
+            return Key8;
+        case SDLK_9:
+            return Key9;
+        case SDLK_COLON:
+            return KeyUnknown;
+        case SDLK_SEMICOLON:
+            return KeyUnknown;
+        case SDLK_LESS:
+            return KeyUnknown;
+        case SDLK_EQUALS:
+            return KeyUnknown;
+        case SDLK_GREATER:
+            return KeyUnknown;
+        case SDLK_QUESTION:
+            return KeyUnknown;
+        case SDLK_AT:
+            return KeyUnknown;
+        case SDLK_LEFTBRACKET:
+            return KeyUnknown;
+        case SDLK_BACKSLASH:
+            return KeyUnknown;
+        case SDLK_RIGHTBRACKET:
+            return KeyUnknown;
+        case SDLK_CARET:
+            return KeyUnknown;
+        case SDLK_UNDERSCORE:
+            return KeyUnknown;
+        case SDLK_BACKQUOTE:
+            return KeyUnknown;
+        case SDLK_a:
+            return KeyA;
+        case SDLK_b:
+            return KeyB;
+        case SDLK_c:
+            return KeyC;
+        case SDLK_d:
+            return KeyD;
+        case SDLK_e:
+            return KeyE;
+        case SDLK_f:
+            return KeyF;
+        case SDLK_g:
+            return KeyG;
+        case SDLK_h:
+            return KeyG;
+        case SDLK_i:
+            return KeyI;
+        case SDLK_j:
+            return KeyJ;
+        case SDLK_k:
+            return KeyK;
+        case SDLK_l:
+            return KeyL;
+        case SDLK_m:
+            return KeyM;
+        case SDLK_n:
+            return KeyN;
+        case SDLK_o:
+            return KeyO;
+        case SDLK_p:
+            return KeyP;
+        case SDLK_q:
+            return KeyQ;
+        case SDLK_r:
+            return KeyR;
+        case SDLK_s:
+            return KeyS;
+        case SDLK_t:
+            return KeyT;
+        case SDLK_u:
+            return KeyU;
+        case SDLK_v:
+            return KeyV;
+        case SDLK_w:
+            return KeyW;
+        case SDLK_x:
+            return KeyX;
+        case SDLK_y:
+            return KeyY;
+        case SDLK_z:
+            return KeyZ;
+        case SDLK_CAPSLOCK:
+            return KeyCapsLock;
+        case SDLK_F1:
+            return KeyF1;
+        case SDLK_F2:
+            return KeyF2;
+        case SDLK_F3:
+            return KeyF3;
+        case SDLK_F4:
+            return KeyF4;
+        case SDLK_F5:
+            return KeyF5;
+        case SDLK_F6:
+            return KeyF6;
+        case SDLK_F7:
+            return KeyF7;
+        case SDLK_F8:
+            return KeyF8;
+        case SDLK_F9:
+            return KeyF9;
+        case SDLK_F10:
+            return KeyF10;
+        case SDLK_F11:
+            return KeyF11;
+        case SDLK_F12:
+            return KeyF12;
+        case SDLK_PRINTSCREEN:
+            return KeyPrint;
+        case SDLK_SCROLLLOCK:
+            return KeyScrollLock;
+        case SDLK_PAUSE:
+            return KeyPause;
+        case SDLK_INSERT:
+            return KeyInsert;
+        case SDLK_HOME:
+            return KeyHome;
+        case SDLK_PAGEUP:
+            return KeyPageUp;
+        case SDLK_DELETE:
+            return KeyDelete;
+        case SDLK_END:
+            return KeyEnd;
+        case SDLK_PAGEDOWN:
+            return KeyPageDown;
+        case SDLK_RIGHT:
+            return KeyRight;
+        case SDLK_LEFT:
+            return KeyLeft;
+        case SDLK_DOWN:
+            return KeyDown;
+        case SDLK_UP:
+            return KeyUp;
+        case SDLK_NUMLOCKCLEAR:
+            return KeyUnknown;
+        case SDLK_KP_DIVIDE:
+            return KeyUnknown;
+        case SDLK_KP_MULTIPLY:
+            return KeyUnknown;
+        case SDLK_KP_MINUS:
+            return KeyUnknown;
+        case SDLK_KP_PLUS:
+            return KeyUnknown;
+        case SDLK_KP_ENTER:
+            return KeyUnknown;
+        case SDLK_KP_1:
+            return KeyUnknown;
+        case SDLK_KP_2:
+            return KeyUnknown;
+        case SDLK_KP_3:
+            return KeyUnknown;
+        case SDLK_KP_4:
+            return KeyUnknown;
+        case SDLK_KP_5:
+            return KeyUnknown;
+        case SDLK_KP_6:
+            return KeyUnknown;
+        case SDLK_KP_7:
+            return KeyUnknown;
+        case SDLK_KP_8:
+            return KeyUnknown;
+        case SDLK_KP_9:
+            return KeyUnknown;
+        case SDLK_KP_0:
+            return KeyUnknown;
+        case SDLK_KP_PERIOD:
+            return KeyUnknown;
+        case SDLK_APPLICATION:
+            return KeyUnknown;
+        case SDLK_POWER:
+            return KeyUnknown;
+        case SDLK_KP_EQUALS:
+            return KeyUnknown;
+        case SDLK_F13:
+            return KeyUnknown;
+        case SDLK_F14:
+            return KeyUnknown;
+        case SDLK_F15:
+            return KeyUnknown;
+        case SDLK_F16:
+            return KeyUnknown;
+        case SDLK_F17:
+            return KeyUnknown;
+        case SDLK_F18:
+            return KeyUnknown;
+        case SDLK_F19:
+            return KeyUnknown;
+        case SDLK_F20:
+            return KeyUnknown;
+        case SDLK_F21:
+            return KeyUnknown;
+        case SDLK_F22:
+            return KeyUnknown;
+        case SDLK_F23:
+            return KeyUnknown;
+        case SDLK_F24:
+            return KeyUnknown;
+        case SDLK_EXECUTE:
+            return KeyUnknown;
+        case SDLK_HELP:
+            return KeyUnknown;
+        case SDLK_MENU:
+            return KeyUnknown;
+        case SDLK_SELECT:
+            return KeyUnknown;
+        case SDLK_STOP:
+            return KeyUnknown;
+        case SDLK_AGAIN:
+            return KeyUnknown;
+        case SDLK_UNDO:
+            return KeyUnknown;
+        case SDLK_CUT:
+            return KeyUnknown;
+        case SDLK_COPY:
+            return KeyUnknown;
+        case SDLK_PASTE:
+            return KeyUnknown;
+        case SDLK_FIND:
+            return KeyUnknown;
+        case SDLK_MUTE:
+            return KeyUnknown;
+        case SDLK_VOLUMEUP:
+            return KeyUnknown;
+        case SDLK_VOLUMEDOWN:
+            return KeyUnknown;
+        case SDLK_KP_COMMA:
+            return KeyUnknown;
+        case SDLK_KP_EQUALSAS400:
+            return KeyUnknown;
+        case SDLK_ALTERASE:
+            return KeyUnknown;
+        case SDLK_SYSREQ:
+            return KeyUnknown;
+        case SDLK_CANCEL:
+            return KeyUnknown;
+        case SDLK_CLEAR:
+            return KeyUnknown;
+        case SDLK_PRIOR:
+            return KeyUnknown;
+        case SDLK_RETURN2:
+            return KeyUnknown;
+        case SDLK_SEPARATOR:
+            return KeyUnknown;
+        case SDLK_OUT:
+            return KeyUnknown;
+        case SDLK_OPER:
+            return KeyUnknown;
+        case SDLK_CLEARAGAIN:
+            return KeyUnknown;
+        case SDLK_CRSEL:
+            return KeyUnknown;
+        case SDLK_EXSEL:
+            return KeyUnknown;
+        case SDLK_KP_00:
+            return KeyUnknown;
+        case SDLK_KP_000:
+            return KeyUnknown;
+        case SDLK_THOUSANDSSEPARATOR:
+            return KeyUnknown;
+        case SDLK_DECIMALSEPARATOR:
+            return KeyUnknown;
+        case SDLK_CURRENCYUNIT:
+            return KeyUnknown;
+        case SDLK_CURRENCYSUBUNIT:
+            return KeyUnknown;
+        case SDLK_KP_LEFTPAREN:
+            return KeyUnknown;
+        case SDLK_KP_RIGHTPAREN:
+            return KeyUnknown;
+        case SDLK_KP_LEFTBRACE:
+            return KeyUnknown;
+        case SDLK_KP_RIGHTBRACE:
+            return KeyUnknown;
+        case SDLK_KP_TAB:
+            return KeyUnknown;
+        case SDLK_KP_BACKSPACE:
+            return KeyUnknown;
+        case SDLK_KP_A:
+            return KeyUnknown;
+        case SDLK_KP_B:
+            return KeyUnknown;
+        case SDLK_KP_C:
+            return KeyUnknown;
+        case SDLK_KP_D:
+            return KeyUnknown;
+        case SDLK_KP_E:
+            return KeyUnknown;
+        case SDLK_KP_F:
+            return KeyUnknown;
+        case SDLK_KP_XOR:
+            return KeyUnknown;
+        case SDLK_KP_POWER:
+            return KeyUnknown;
+        case SDLK_KP_PERCENT:
+            return KeyUnknown;
+        case SDLK_KP_LESS:
+            return KeyUnknown;
+        case SDLK_KP_GREATER:
+            return KeyUnknown;
+        case SDLK_KP_AMPERSAND:
+            return KeyUnknown;
+        case SDLK_KP_DBLAMPERSAND:
+            return KeyUnknown;
+        case SDLK_KP_VERTICALBAR:
+            return KeyUnknown;
+        case SDLK_KP_DBLVERTICALBAR:
+            return KeyUnknown;
+        case SDLK_KP_COLON:
+            return KeyUnknown;
+        case SDLK_KP_HASH:
+            return KeyUnknown;
+        case SDLK_KP_SPACE:
+            return KeyUnknown;
+        case SDLK_KP_AT:
+            return KeyUnknown;
+        case SDLK_KP_EXCLAM:
+            return KeyUnknown;
+        case SDLK_KP_MEMSTORE:
+            return KeyUnknown;
+        case SDLK_KP_MEMRECALL:
+            return KeyUnknown;
+        case SDLK_KP_MEMCLEAR:
+            return KeyUnknown;
+        case SDLK_KP_MEMADD:
+            return KeyUnknown;
+        case SDLK_KP_MEMSUBTRACT:
+            return KeyUnknown;
+        case SDLK_KP_MEMMULTIPLY:
+            return KeyUnknown;
+        case SDLK_KP_MEMDIVIDE:
+            return KeyUnknown;
+        case SDLK_KP_PLUSMINUS:
+            return KeyUnknown;
+        case SDLK_KP_CLEAR:
+            return KeyUnknown;
+        case SDLK_KP_CLEARENTRY:
+            return KeyUnknown;
+        case SDLK_KP_BINARY:
+            return KeyUnknown;
+        case SDLK_KP_OCTAL:
+            return KeyUnknown;
+        case SDLK_KP_DECIMAL:
+            return KeyUnknown;
+        case SDLK_KP_HEXADECIMAL:
+            return KeyUnknown;
+        case SDLK_LCTRL:
+            return KeyLeftCtrl;
+        case SDLK_LSHIFT:
+            return KeyLeftShift;
+        case SDLK_LALT:
+            return KeyLeftAlt;
+        case SDLK_LGUI:
+            return KeyUnknown;
+        case SDLK_RCTRL:
+            return KeyRightControl;
+        case SDLK_RSHIFT:
+            return KeyRightShift;
+        case SDLK_RALT:
+            return KeyRightAlt;
+        case SDLK_RGUI:
+            return KeyUnknown;
+        case SDLK_MODE:
+            return KeyUnknown;
+        case SDLK_AUDIONEXT:
+            return KeyUnknown;
+        case SDLK_AUDIOPREV:
+            return KeyUnknown;
+        case SDLK_AUDIOSTOP:
+            return KeyUnknown;
+        case SDLK_AUDIOPLAY:
+            return KeyUnknown;
+        case SDLK_AUDIOMUTE:
+            return KeyUnknown;
+        case SDLK_MEDIASELECT:
+            return KeyUnknown;
+        case SDLK_WWW:
+            return KeyUnknown;
+        case SDLK_MAIL:
+            return KeyUnknown;
+        case SDLK_CALCULATOR:
+            return KeyUnknown;
+        case SDLK_COMPUTER:
+            return KeyUnknown;
+        case SDLK_AC_SEARCH:
+            return KeyUnknown;
+        case SDLK_AC_HOME:
+            return KeyUnknown;
+        case SDLK_AC_BACK:
+            return KeyUnknown;
+        case SDLK_AC_FORWARD:
+            return KeyUnknown;
+        case SDLK_AC_STOP:
+            return KeyUnknown;
+        case SDLK_AC_REFRESH:
+            return KeyUnknown;
+        case SDLK_AC_BOOKMARKS:
+            return KeyUnknown;
+        case SDLK_BRIGHTNESSDOWN:
+            return KeyUnknown;
+        case SDLK_BRIGHTNESSUP:
+            return KeyUnknown;
+        case SDLK_DISPLAYSWITCH:
+            return KeyUnknown;
+        case SDLK_KBDILLUMTOGGLE:
+            return KeyUnknown;
+        case SDLK_KBDILLUMDOWN:
+            return KeyUnknown;
+        case SDLK_KBDILLUMUP:
+            return KeyUnknown;
+        case SDLK_EJECT:
+            return KeyUnknown;
+        case SDLK_SLEEP:
+            return KeyUnknown;
+        case SDLK_APP1:
+            return KeyUnknown;
+        case SDLK_APP2:
+            return KeyUnknown;
+        case SDLK_AUDIOREWIND:
+            return KeyUnknown;
+        case SDLK_AUDIOFASTFORWARD:
+            return KeyUnknown;
+        default: ;
+    }
+
+    return KeyUnknown;
+}
+
+static const char *keyNames[] = {
+    "<unknown:00>",
+    "KeyEscape", // = 0x01,
+    "Key1", // = 0x02,
+    "Key2", // = 0x03,
+    "Key3", // = 0x04,
+    "Key4", // = 0x05,
+    "Key5", // = 0x06,
+    "Key6", // = 0x07,
+    "Key7", // = 0x08,
+    "Key8", // = 0x09,
+    "Key9", // = 0x0a,
+    "Key0", // = 0x0b,
+    "KeyMinus", // = 0x0c,
+    "KeyEqual", // = 0x0d,
+    "KeyBackspace", // = 0x0e,
+    "KeyTab", // = 0x0f,
+    
+    "KeyQ", // = 0x10,
+    "KeyW", // = 0x11,
+    "KeyE", // = 0x12,
+    "KeyR", // = 0x13,
+    "KeyT", // = 0x14,
+    "KeyY", // = 0x15,
+    "KeyU", // = 0x16,
+    "KeyI", // = 0x17,
+    "KeyO", // = 0x18,
+    "KeyP", // = 0x19,
+    "KeyBracketLeft", // = 0x1a,
+    "KeyBracketRight", // = 0x1b,
+    "KeyEnter", // = 0x1c,
+    "KeyLeftCtrl", // = 0x1d,
+    "KeyA", // = 0x1e,
+    "KeyS", // = 0x1f,
+    
+    "KeyD", // = 0x20,
+    "KeyF", // = 0x21,
+    "KeyG", // = 0x22,
+    "KeyH", // = 0x23,
+    "KeyJ", // = 0x24,
+    "KeyK", // = 0x25,
+    "KeyL", // = 0x26,
+    "KeySemicolon", // = 0x27,
+    "KeyApostrophe", // = 0x28,
+    "KeyBacktick", // = 0x29,
+    "KeyLeftShift", // = 0x2a,
+    "KeyBackslash", // = 0x2b,
+    "KeyZ", // = 0x2c,
+    "KeyX", // = 0x2d,
+    "KeyC", // = 0x2e,
+    "KeyV", // = 0x2f,
+    
+    "KeyB", // = 0x30,
+    "KeyN", // = 0x31,
+    "KeyM", // = 0x32,
+    "KeyComma", // = 0x33,
+    "KeyPeriod", // = 0x34,
+    "KeySlash", // = 0x35,
+    "KeyRightShift", // = 0x36,
+    "KeyKeypadMultiply", // = 0x37,
+    "KeyLeftAlt", // = 0x38,
+    "KeySpace", // = 0x39,
+    "KeyCapsLock", // = 0x3a,
+    "KeyF1", // = 0x3b,
+    "KeyF2", // = 0x3c,
+    "KeyF3", // = 0x3d,
+    "KeyF4", // = 0x3e,
+    "KeyF5", // = 0x3f,
+    
+    "KeyF6", // = 0x40,
+    "KeyF7", // = 0x41,
+    "KeyF8", // = 0x42,
+    "KeyF9", // = 0x43,
+    "KeyF10", // = 0x44,
+    "KeyNumLock", // = 0x45,
+    "KeyScrollLock", // = 0x46,
+    "KeyKeypad7", // = 0x47,
+    "KeyKeypad8", // = 0x48,
+    "KeyKeypad9", // = 0x49,
+    "KeyKeypadMinus", // = 0x4a,
+    "KeyKeypad4", // = 0x4b,
+    "KeyKeypad5", // = 0x4c,
+    "KeyKeypad6", // = 0x4d,
+    "KeyKeypadPlus", // = 0x4e,
+    "KeyKeypad1", // = 0x4f,
+    
+    "KeyKeypad2", // = 0x50,
+    "KeyKeypad3", // = 0x51,
+    "KeyKeypad0", // = 0x52,
+    "KeyKeypadPeriod", // = 0x53,
+    "<unknown:54>",
+    "<unknown:55>",
+    "<unknown:56>",
+    "KeyF11", // = 0x57,
+    "KeyF12", // = 0x58,
+    "<unknown:59>",
+    "<unknown:5a>",
+    "<unknown:5b>",
+    "<unknown:5c>",
+    "<unknown:5d>",
+    "<unknown:5e>",
+    "<unknown:5f>",
+
+    "<unknown:60>",
+    "<unknown:61>",
+    "<unknown:62>",
+    "<unknown:63>",
+    "<unknown:64>",
+    "<unknown:65>",
+    "<unknown:66>",
+    "<unknown:67>",
+    "<unknown:68>",
+    "<unknown:69>",
+    "<unknown:6a>",
+    "<unknown:6b>",
+    "<unknown:6c>",
+    "<unknown:6d>",
+    "<unknown:6e>",
+    "<unknown:6f>",
+
+    "<unknown:70>",
+    "<unknown:71>",
+    "<unknown:72>",
+    "<unknown:73>",
+    "<unknown:74>",
+    "<unknown:75>",
+    "<unknown:76>",
+    "<unknown:77>",
+    "<unknown:78>",
+    "<unknown:79>",
+    "<unknown:7a>",
+    "<unknown:7b>",
+    "<unknown:7c>",
+    "<unknown:7d>",
+    "<unknown:7e>",
+    "<unknown:7f>",
+
+    "<unknown:80>",
+    "<unknown:81>",
+    "<unknown:82>",
+    "<unknown:83>",
+    "<unknown:84>",
+    "<unknown:85>",
+    "<unknown:86>",
+    "<unknown:87>",
+    "<unknown:88>",
+    "<unknown:89>",
+    "<unknown:8a>",
+    "<unknown:8b>",
+    "<unknown:8c>",
+    "<unknown:8d>",
+    "<unknown:8e>",
+    "<unknown:8f>",
+
+    "KeyMediaPrev", // = 0x90,
+    "<unknown:91>",
+    "<unknown:92>",
+    "<unknown:93>",
+    "<unknown:94>",
+    "<unknown:95>",
+    "<unknown:96>",
+    "<unknown:97>",
+    "<unknown:98>",
+    "KeyMediaNext", // = 0x99,
+    "<unknown:9a>",
+    "<unknown:9b>",
+    "KeyKeypadEnter", // = 0x9c,
+    "KeyRightControl", // = 0x9d,
+    "<unknown:9e>",
+    "<unknown:9f>",
+
+    "KeyMediaMute", // = 0xa0,
+    "KeyMediaCalculator", // = 0xa1,
+    "KeyMediaPlay", // = 0xa2,
+    "<unknown:a3>",
+    "KeyMediaStop", // = 0xa4,
+    "<unknown:a5>",
+    "<unknown:a6>",
+    "<unknown:a7>",
+    "<unknown:a8>",
+    "<unknown:a9>",
+    "<unknown:aa>",
+    "<unknown:ab>",
+    "<unknown:ac>",
+    "<unknown:ad>",
+    "KeyMediaVolumeDown", // = 0xae,
+    "<unknown:af>",
+
+    "KeyMediaVolumeUp", // = 0xb0,
+    "<unknown:b1>",
+    "KeyMediaWww", // = 0xb2,
+    "<unknown:b3>",
+    "<unknown:b4>",
+    "KeyKeypadDivide", // = 0xb5,
+    "<unknown:b6>",
+    "<unknown:b7>",
+    "KeyRightAlt", // = 0xb8,
+    "<unknown:b9>",
+    "<unknown:ba>",
+    "<unknown:bb>",
+    "<unknown:bc>",
+    "<unknown:bd>",
+    "<unknown:be>",
+    "<unknown:bf>",
+
+    "<unknown:c0>",
+    "<unknown:c1>",
+    "<unknown:c2>",
+    "<unknown:c3>",
+    "<unknown:c4>",
+    "<unknown:c5>",
+    "<unknown:c6>",
+    "KeyHome", // = 0xc7,
+    "KeyUp", // = 0xc8,
+    "KeyPageUp", // = 0xc9,
+    "<unknown:ca>",
+    "KeyLeft", // = 0xcb,
+    "<unknown:cc>",
+    "KeyRight", // = 0xcd,
+    "<unknown:ce>",
+    "KeyEnd", // = 0xcf,
+
+    "KeyDown", // = 0xd0,
+    "KeyPageDown", // = 0xd1,
+    "KeyInsert", // = 0xd2,
+    "KeyDelete", // = 0xd3,
+    "<unknown:d4>",
+    "<unknown:d5>",
+    "<unknown:d6>",
+    "<unknown:d7>",
+    "<unknown:d8>",
+    "<unknown:d9>",
+    "<unknown:da>",
+    "KeyLeftGui", // = 0xdb,
+    "KeyRightGui", // = 0xdc,
+    "KeyApps", // = 0xdd,
+    "KeyAcpiPower", // = 0xde,
+    "KeyAcpiSleep", // = 0xdf,
+
+    "<unknown:e0>",
+    "<unknown:e1>",
+    "<unknown:e2>",
+    "KeyAcpiWake", // = 0xe3,
+    "<unknown:e4>",
+    "KeyMediaWwwSearch", // = 0xe5,
+    "KeyMediaWwwFavorites", // = 0xe6,
+    "KeyMediaWwwRefresh", // = 0xe7,
+    "KeyMediaWwwStop", // = 0xe8,
+    "KeyMediaWwwForward", // = 0xe9,
+    "KeyMediaWwwBack", // = 0xea,
+    "KeyMediaMyComputer", // = 0xeb,
+    "KeyMediaEmail", // = 0xec,
+    "KeyMediaSelect", // = 0xed,
+    "<unknown:ee>",
+    "<unknown:ef>",
+
+    "<unknown:f0>",
+    "<unknown:f1>",
+    "<unknown:f2>",
+    "<unknown:f3>",
+    "<unknown:f4>",
+    "<unknown:f5>",
+    "<unknown:f6>",
+    "<unknown:f7>",
+    "<unknown:f8>",
+    "<unknown:f9>",
+    "<unknown:fa>",
+    "<unknown:fb>",
+    "<unknown:fc>",
+    "<unknown:fd>",
+    "KeyPrint", // = 0xfe,
+    "KeyPause", // = 0xff,
+};
+
+void keyboardIsr() {
+    keyboard.Isr();
+}
+
+Keyboard::Keyboard() {
+    // TODO
+}
+
+Keyboard::~Keyboard() {
+    // TODO
+}
+
+Keyboard::KeyHandleFunction Keyboard::setKeyUpHandler(KeyHandleFunction handler) {
+    auto oldHandler = _keyUpHandler;
+    _keyUpHandler = handler;
+    return oldHandler;
+}
+
+Keyboard::KeyHandleFunction Keyboard::setKeyDownHandler(KeyHandleFunction handler) {
+    auto oldHandler = _keyDownHandler;
+    _keyDownHandler = handler;
+    return oldHandler;
+}
+
+Keyboard::KeyHandleFunction Keyboard::setKeyRepeatHandler(KeyHandleFunction handler) {
+    auto oldHandler = _keyRepeatHandler;
+    _keyRepeatHandler = handler;
+    return oldHandler;
+}
+
+const char *Keyboard::getKeyName(unsigned char keyCode) {
+    return keyNames[keyCode];
+}
+
+void Keyboard::Isr() {
+    // TODO
+}
+
+void Keyboard::keyDown(SDL_Keycode keyCode) {
+    auto c = mapSdlKeycode(keyCode);
+    if (keyState[c]) {
+        if (_keyRepeatHandler) _keyRepeatHandler(c);
+    } else {
+        keyState[c] = true;
+        if (_keyDownHandler) _keyDownHandler(c);
+    }
+}
+
+void Keyboard::keyUp(SDL_Keycode keyCode) {
+    auto c = mapSdlKeycode(keyCode);
+    keyState[c] = false;
+    if (_keyUpHandler) _keyUpHandler(c);
+}

system/sdl/Keyboard.h

@@ -0,0 +1,178 @@
+#ifndef GAME_KEYBOARD_H
+#define GAME_KEYBOARD_H
+
+#include <SDL.h>
+
+#define KEY_MAX 256
+
+enum {
+    KeyUnknown = 0x00,
+    KeyEscape = 0x01,
+    Key1 = 0x02,
+    Key2 = 0x03,
+    Key3 = 0x04,
+    Key4 = 0x05,
+    Key5 = 0x06,
+    Key6 = 0x07,
+    Key7 = 0x08,
+    Key8 = 0x09,
+    Key9 = 0x0a,
+    Key0 = 0x0b,
+    KeyMinus = 0x0c,
+    KeyEqual = 0x0d,
+    KeyBackspace = 0x0e,
+    KeyTab = 0x0f,
+    KeyQ = 0x10,
+    KeyW = 0x11,
+    KeyE = 0x12,
+    KeyR = 0x13,
+    KeyT = 0x14,
+    KeyY = 0x15,
+    KeyU = 0x16,
+    KeyI = 0x17,
+    KeyO = 0x18,
+    KeyP = 0x19,
+    KeyBracketLeft = 0x1a,
+    KeyBracketRight = 0x1b,
+    KeyEnter = 0x1c,
+    KeyLeftCtrl = 0x1d,
+    KeyA = 0x1e,
+    KeyS = 0x1f,
+    KeyD = 0x20,
+    KeyF = 0x21,
+    KeyG = 0x22,
+    KeyH = 0x23,
+    KeyJ = 0x24,
+    KeyK = 0x25,
+    KeyL = 0x26,
+    KeySemicolon = 0x27,
+    KeyApostrophe = 0x28,
+    KeyBacktick = 0x29,
+    KeyLeftShift = 0x2a,
+    KeyBackslash = 0x2b,
+    KeyZ = 0x2c,
+    KeyX = 0x2d,
+    KeyC = 0x2e,
+    KeyV = 0x2f,
+    KeyB = 0x30,
+    KeyN = 0x31,
+    KeyM = 0x32,
+    KeyComma = 0x33,
+    KeyPeriod = 0x34,
+    KeySlash = 0x35,
+    KeyRightShift = 0x36,
+    KeyKeypadMultiply = 0x37,
+    KeyLeftAlt = 0x38,
+    KeySpace = 0x39,
+    KeyCapsLock = 0x3a,
+    KeyF1 = 0x3b,
+    KeyF2 = 0x3c,
+    KeyF3 = 0x3d,
+    KeyF4 = 0x3e,
+    KeyF5 = 0x3f,
+    KeyF6 = 0x40,
+    KeyF7 = 0x41,
+    KeyF8 = 0x42,
+    KeyF9 = 0x43,
+    KeyF10 = 0x44,
+    KeyNumLock = 0x45,
+    KeyScrollLock = 0x46,
+    KeyKeypad7 = 0x47,
+    KeyKeypad8 = 0x48,
+    KeyKeypad9 = 0x49,
+    KeyKeypadMinus = 0x4a,
+    KeyKeypad4 = 0x4b,
+    KeyKeypad5 = 0x4c,
+    KeyKeypad6 = 0x4d,
+    KeyKeypadPlus = 0x4e,
+    KeyKeypad1 = 0x4f,
+    KeyKeypad2 = 0x50,
+    KeyKeypad3 = 0x51,
+    KeyKeypad0 = 0x52,
+    KeyKeypadPeriod = 0x53,
+    KeyF11 = 0x57,
+    KeyF12 = 0x58,
+    KeyMediaPrev = 0x90,
+    KeyMediaNext = 0x99,
+    KeyKeypadEnter = 0x9c,
+    KeyRightControl = 0x9d,
+    KeyMediaMute = 0xa0,
+    KeyMediaCalculator = 0xa1,
+    KeyMediaPlay = 0xa2,
+    KeyMediaStop = 0xa4,
+    KeyMediaVolumeDown = 0xae,
+    KeyMediaVolumeUp = 0xb0,
+    KeyMediaWww = 0xb2,
+    KeyKeypadDivide = 0xb5,
+    KeyRightAlt = 0xb8,
+    KeyHome = 0xc7,
+    KeyUp = 0xc8,
+    KeyPageUp = 0xc9,
+    KeyLeft = 0xcb,
+    KeyRight = 0xcd,
+    KeyEnd = 0xcf,
+    KeyDown = 0xd0,
+    KeyPageDown = 0xd1,
+    KeyInsert = 0xd2,
+    KeyDelete = 0xd3,
+    KeyLeftGui = 0xdb,
+    KeyRightGui = 0xdc,
+    KeyApps = 0xdd,
+    KeyAcpiPower = 0xde,
+    KeyAcpiSleep = 0xdf,
+    KeyAcpiWake = 0xe3,
+    KeyMediaWwwSearch = 0xe5,
+    KeyMediaWwwFavorites = 0xe6,
+    KeyMediaWwwRefresh = 0xe7,
+    KeyMediaWwwStop = 0xe8,
+    KeyMediaWwwForward = 0xe9,
+    KeyMediaWwwBack = 0xea,
+    KeyMediaMyComputer = 0xeb,
+    KeyMediaEmail = 0xec,
+    KeyMediaSelect = 0xed,
+    KeyPrint = 0xfe,
+    KeyPause = 0xff,
+};
+
+class Keyboard {
+public:
+    using KeyHandleFunction = void (*)(unsigned char);
+
+    Keyboard();
+    ~Keyboard();
+
+    KeyHandleFunction setKeyUpHandler(KeyHandleFunction handler);
+    KeyHandleFunction setKeyDownHandler(KeyHandleFunction handler);
+    KeyHandleFunction setKeyRepeatHandler(KeyHandleFunction handler);
+
+    bool keyState[KEY_MAX]{};
+
+    const char *getKeyName(unsigned char keyCode);
+private:
+    friend class Events;
+
+    friend void keyboardIsr();
+    void Isr();
+    enum State {
+        Start,
+        Extended,
+        PauseBegin,
+        PausePressed1,
+        PauseReleased1,
+        PrintPressed1,
+        PrintPressed2,
+        PrintReleased1,
+        PrintReleased2,
+    };
+    State _state;
+    KeyHandleFunction _keyDownHandler{nullptr}, _keyUpHandler{nullptr}, _keyRepeatHandler{nullptr};
+
+    void keyDown(SDL_Keycode c);
+
+    void keyUp(SDL_Keycode c);
+
+};
+
+extern Keyboard keyboard;
+
+#endif //GAME_KEYBOARD_H

system/sdl/Opl.cpp

@@ -0,0 +1,7 @@
+#include "../Opl.h"
+
+namespace Opl {
+    void write(uint16_t reg, uint8_t data) {
+        // TODO
+    }
+}

system/sdl/SoundBlaster.cpp

@@ -0,0 +1,19 @@
+#include "../SoundBlaster.h"
+
+SoundBlaster soundblaster;
+
+void soundblasterIsr() {
+    soundblaster.onInterrupt();
+}
+
+SoundBlaster::SoundBlaster() {
+
+}
+
+SoundBlaster::~SoundBlaster() {
+}
+
+void SoundBlaster::onInterrupt() {
+
+}
+

system/sdl/Timer.cpp

@@ -0,0 +1,51 @@
+#include <SDL.h>
+
+#include "../Timer.h"
+
+Timer timer;
+
+SDL_TimerID timerId;
+
+void timerISR() {
+	timer.update();
+}
+
+Timer::Timer() {
+	_freq = 50;
+	timerId = SDL_AddTimer(1000/_freq, [] (Uint32, void*) -> Uint32 {
+		timerISR();
+		return 1000 / timer.getFrequency();
+	}, nullptr);
+}
+
+Timer::~Timer() {
+	SDL_RemoveTimer(timerId);
+}
+
+void Timer::update() {
+	// TODO
+	_ticks++;
+}
+
+uint32_t Timer::getTicks() const {
+	return _ticks;
+}
+
+void Timer::setFrequency(uint16_t freq) {
+	_freq = freq;
+	// TODO
+}
+
+uint16_t Timer::getFrequency() const {
+	return _freq;
+}
+
+void Timer::setDivider(uint16_t div) {
+	// TODO
+}
+
+Timer::Callback Timer::setCallback(Timer::Callback callback) {
+	auto oldCallback = _callback;
+	_callback = callback;
+	return oldCallback;
+}

system/sdl/Video.cpp

@@ -0,0 +1,124 @@
+#include <iostream>
+
+#include "../Video.h"
+
+#include "Events.h"
+
+#define WINDOW_WIDTH 1280
+#define WINDOW_HEIGHT 800
+
+Video video;
+
+Video::Video() {
+	// TODO
+}
+
+Video::~Video() {
+	Exit();
+}
+
+inline void writePixel(SDL_Surface *surface, unsigned x, unsigned y, Uint8 r, Uint8 g, Uint8 b, Uint8 a) {
+	auto row = reinterpret_cast<Uint32*>(static_cast<Uint8*>(surface->pixels) + y * surface->pitch);
+	row[x] = SDL_MapRGBA(surface->format, r, g, b, a);
+}
+
+void Video::Enter() {
+	_window = SDL_CreateWindow("game", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 1280, 800, SDL_WINDOW_SHOWN);
+	if (!_window) {
+		std::cerr << "Error creating SDL window: " << SDL_GetError() << std::endl;
+		abort();
+	}
+
+	_windowSurface = SDL_GetWindowSurface(_window);
+	_fb = SDL_CreateRGBSurfaceWithFormat(0, SCREEN_WIDTH, SCREEN_HEIGHT, 32, SDL_PIXELFORMAT_ARGB8888);
+}
+
+void Video::Exit() {
+	if (_fb) SDL_FreeSurface(_fb);
+	_fb = nullptr;
+
+	SDL_DestroyWindow(_window);
+}
+
+void Video::SetMode(uint8_t mode) {
+	// Ignored
+}
+
+uint8_t Video::GetMode() {
+	// Fixed
+	return 0x13;
+}
+
+void Video::SetPaletteEntry(uint8_t index, PaletteEntry entry) {
+	SetPaletteEntry(index, &entry);
+}
+
+Video::PaletteEntry Video::GetPaletteEntry(uint8_t index) {
+	PaletteEntry entry;
+	GetPaletteEntry(index, &entry);
+	return entry;
+}
+
+void Video::SetPaletteEntry(uint8_t index, PaletteEntry *entry) {
+	_palette[index] = *entry;
+}
+
+void Video::GetPaletteEntry(uint8_t index, PaletteEntry *entry) {
+	*entry = _palette[index];
+}
+
+void *Video::GetFB() {
+	return _renderBuffer;
+}
+
+void Video::WaitForVerticalSync() {
+	auto targetTime = _lastUpdate + std::chrono::microseconds(14286);
+	auto currentTime = std::chrono::steady_clock::now();
+
+	while (currentTime < targetTime) {
+		currentTime = std::chrono::steady_clock::now();
+	}
+	_lastUpdate = currentTime;
+}
+
+void Video::UpdateRect(const Rect &rect) {
+	// Merge rect if it overlaps with an existing rect
+	for (auto i = 0; i < _updateRectIndex; i++) {
+		auto &r = _updatedRects[i];
+		if (r.overlaps(rect)) {
+			r += rect;
+			return;
+		}
+	}
+
+	// Add a new rect to the list
+	_updatedRects[_updateRectIndex++] = rect;
+}
+
+void Video::Flip() {
+	SDL_LockSurface(_fb);
+
+	for (auto i = 0; i <= MAX_UPDATE_RECT_INDEX; i++) {
+		auto &rect = _updatedRects[i];
+		rect.clamp(0, 0, _fb->w, _fb->h);
+
+		for (auto y = rect.y1; y < rect.y2; y++) {
+			for (auto x = rect.x1; x < rect.x2; x++) {
+				auto &paletteEntry = _palette[_renderBuffer[y * SCREEN_WIDTH + x]];
+
+				writePixel(_fb, x, y, paletteEntry.r, paletteEntry.g, paletteEntry.b, 255);
+			}
+		}
+	}
+	SDL_UnlockSurface(_fb);
+
+	SDL_Rect srcRect{0, 0, SCREEN_WIDTH, SCREEN_HEIGHT};
+	SDL_Rect dstRect{0, 0, WINDOW_WIDTH, WINDOW_HEIGHT};
+
+	SDL_BlitScaled(_fb, &srcRect, _windowSurface, &dstRect);
+	SDL_UpdateWindowSurface(_window);
+
+	_updateRectIndex = 0;
+
+	events.poll();
+}

system/sdl/init.cpp

@@ -0,0 +1,21 @@
+#include "../init.h"
+
+#include <iostream>
+#include <SDL.h>
+
+#include "../Video.h"
+
+namespace System {
+    void init() {
+        if (SDL_Init( SDL_INIT_VIDEO | SDL_INIT_TIMER ) < 0) {
+            std::cerr << "Error initializing SDL: " << SDL_GetError() << std::endl;
+            abort();
+        }
+    }
+
+    void terminate() {
+        video.Exit();
+        SDL_Quit();
+    }
+}
+

util/Asm.h

@@ -0,0 +1,68 @@
+#ifndef ASM_H
+#define ASM_H
+
+#include <cstdint>
+
+static inline uint8_t inb(uint16_t port) {
+	uint8_t value;
+	asm volatile ("inb %1, %0" : "=a"(value) : "Nd"(port));
+	return value;
+}
+
+static inline uint16_t inw(uint16_t port) {
+	uint16_t value;
+	asm volatile ("inw %1, %0" : "=a"(value) : "Nd"(port));
+	return value;
+}
+
+static inline uint32_t inl(uint16_t port) {
+	uint32_t value;
+	asm volatile ("inl %1, %0" : "=a"(value) : "Nd"(port));
+	return value;
+}
+
+static inline void outb(uint16_t port, uint8_t value) {
+	asm volatile ("outb %0, %1" : : "a"(value), "Nd"(port));
+}
+
+static inline void outw(uint16_t port, uint16_t value) {
+	asm volatile ("outw %0, %1" : : "a"(value), "Nd"(port));
+}
+
+static inline void outl(uint16_t port, uint32_t value) {
+	asm volatile ("outl %0, %1" : : "a"(value), "Nd"(port));
+}
+
+static inline void enableInterrupts() {
+	asm volatile ("sti": : :"memory");
+}
+
+static inline void disableInterrupts() {
+	asm volatile ("cli": : :"memory");
+}
+
+static inline uint32_t eflags() {
+	uint32_t value;
+	asm volatile ( "pushf\n\t"
+				   "popl %0"
+	: "=g"(value));
+	return value;
+}
+
+static inline bool interruptsEnabled() {
+	return (eflags() & (1u << 9u)) != 0;
+}
+
+static void pmInterruptCall(unsigned short selector, unsigned long offset) {
+    __asm__ __volatile__ (
+		"pushf\n"				  // Push EFLAGS
+        "mov %0, %%ax\n"          // Load the segment selector into AX
+        "mov %%ax, %%ds\n"        // Move it to DS (or another segment register)
+        "call *%1\n"              // Perform the indirect far call using the offset
+        : // No output operands
+        : "r" (selector), "r" (offset) // Input operands
+        : "%ax"                   // Clobbered register
+    );
+}
+
+#endif

util/Bmp.cpp

@@ -0,0 +1,97 @@
+#include "Bmp.h"
+
+#include <cstdio>
+
+#include "Files.h"
+
+namespace Bmp {
+    Bitmap loadFromMemory(void *buf, size_t len) {
+        if (len < sizeof (BmpFileHeader) + sizeof (BmpInfoHeader)) return {};
+
+        auto fileHeader = reinterpret_cast<BmpFileHeader *>(buf);
+        auto infoHeader = reinterpret_cast<BmpInfoHeader *>(fileHeader + 1);
+
+        if (fileHeader->signature != 0x4d42) {
+            printf("Invalid signature\n");
+            return {};
+        }
+        if (len < fileHeader->fileSize) {
+            printf("File too small\n");
+            return {};
+        }
+        if (infoHeader->headerSize != 40) {
+            printf("Invalid header size\n");
+            return {};
+        }
+        if (infoHeader->width < 0 || infoHeader->height < 0 || infoHeader->planes != 1) {
+            printf("Invalid width/height/bit planes\n");
+
+            return {};
+        }
+        if (infoHeader->bitsPerPixel != 1 && infoHeader->bitsPerPixel != 4 && infoHeader->bitsPerPixel != 8) {
+            printf("Unsupported bpp %u\n", infoHeader->bitsPerPixel);
+
+            return {};
+        }
+        if (infoHeader->compression != BmpInfoHeader::CompressionType::Rgb) {
+            printf("Unsupported compression\n");
+
+            return {};
+        }
+
+        // TODO check imageSize
+
+        Bitmap bitmap(infoHeader->width, infoHeader->height);
+
+        // Read color table
+        auto colorTable = reinterpret_cast<uint8_t *>(infoHeader + 1);
+        for (auto i = 0; i < infoHeader->colorsUsed; i++) {
+            Video::PaletteEntry paletteEntry;
+            paletteEntry.b = colorTable[4 * i + 0];
+            paletteEntry.g = colorTable[4 * i + 1];
+            paletteEntry.r = colorTable[4 * i + 2];
+            bitmap.SetPaletteEntry(i, paletteEntry);
+        }
+
+        // Read pixel data
+        auto data = static_cast<uint8_t *>(buf) + fileHeader->offset;
+        auto rowLength = infoHeader->width;
+        if (infoHeader->bitsPerPixel == 1) rowLength = (rowLength + 7) >> 3;
+        else if (infoHeader->bitsPerPixel == 4) rowLength = (rowLength + 1) >> 1;
+        auto stride = (rowLength + 3) >> 2 << 2;
+        for (auto y = 0u; y < infoHeader->height; y++) {
+            for (auto x = 0u; x < infoHeader->width; x++) {
+                uint8_t pv = 0;
+                switch (infoHeader->bitsPerPixel) {
+                    case 1: {
+                        const auto byte = data[(infoHeader->height - y - 1) * stride + (x >> 3)];
+                        auto pixelOffset = x & 7;
+                        pv = (byte >> (7 - pixelOffset)) & 1;
+                        break;
+                    }
+                    case 4: {
+                        const auto byte = data[(infoHeader->height - y - 1) * stride + (x >> 1)];
+                        pv = x & 1 ? byte & 0xf : byte >> 4;
+                        break;
+                    }
+                    case 8: {
+                        pv = data[(infoHeader->height - y - 1) * stride + x];
+                        break;
+                    }
+                }
+                bitmap.SetPixel(x, y, pv);
+            }
+        }
+
+        return bitmap;
+    }
+
+    Bitmap loadFromFile(const char* path) {
+        void *data;
+        auto len = Files::allocateBufferAndLoadFromFile(path, &data);
+        auto bitmap = loadFromMemory(data, len);
+        Files::deleteBuffer(data);
+
+        return bitmap;
+    }
+}

util/Bmp.h

@@ -0,0 +1,48 @@
+#ifndef GAME_BMPLOADER_H
+#define GAME_BMPLOADER_H
+
+#include <cstddef>
+#include "../graphics/Bitmap.h"
+
+namespace Bmp {
+    struct BmpFileHeader {
+        uint16_t signature;
+        uint32_t fileSize;
+        uint16_t reserved1;
+        uint16_t reserved2;
+        uint32_t offset;
+    } __attribute__((__packed__));
+
+    struct BmpInfoHeader {
+        uint32_t headerSize;
+        uint32_t width;
+        uint32_t height;
+        uint16_t planes;
+        uint16_t bitsPerPixel;
+        uint32_t compression;
+        uint32_t imageSize;
+        uint32_t horizontalResolution;
+        uint32_t verticalResolution;
+        uint32_t colorsUsed;
+        uint32_t colorsImportant;
+
+        enum CompressionType {
+            Rgb = 0,
+            Rle8,
+            Rle4,
+            Bitfields,
+            Jpeg,
+            Png,
+            Alphabitfields,
+            Cmyk,
+            CmykRle8,
+            CmykRle4,
+        };
+    } __attribute__((__packed__));
+
+    Bitmap loadFromMemory(void *buf, size_t len);
+    Bitmap loadFromFile(const char* path);
+};
+
+
+#endif //GAME_BMPLOADER_H

util/Files.cpp

@@ -0,0 +1,27 @@
+#include "Files.h"
+
+#include <cstdio>
+
+size_t Files::allocateBufferAndLoadFromFile(const char *path, void **bufferPointer) {
+    auto fp = fopen(path, "rb");
+    if (!fp) {
+        *bufferPointer = nullptr;
+        return 0;
+    }
+
+    fseek(fp, 0, SEEK_END);
+    size_t len = ftell(fp);
+    fseek(fp, 0, SEEK_SET);
+
+    auto data = new unsigned char[len];
+    fread(data, 1, len, fp);
+    fclose(fp);
+
+    *bufferPointer = data;
+    return len;
+}
+
+void Files::deleteBuffer(void *buffer) {
+    delete[] static_cast<unsigned char*>(buffer);
+}
+

util/Files.h

@@ -0,0 +1,10 @@
+#ifndef GAME_FILES_H
+#define GAME_FILES_H
+#include <stddef.h>
+
+namespace Files {
+    size_t allocateBufferAndLoadFromFile(const char *path, void **bufferPointer);
+    void deleteBuffer(void *);
+}
+
+#endif //GAME_FILES_H

util/Gbm.cpp

@@ -0,0 +1,68 @@
+#include "Gbm.h"
+
+#include <cstdio>
+
+#include "Files.h"
+
+#define GBM_SIGNATURE 0x204d4247
+
+Bitmap Gbm::loadFromMemory(const void *data, size_t size) {
+    // Check for minimum
+    if (size < sizeof (uint32_t) + sizeof (uint16_t) + sizeof (uint16_t) + 16 * 3) return {};
+
+    auto gbm = static_cast<const GbmHeader *>(data);
+
+    if (gbm->signature != GBM_SIGNATURE) return {};
+    if (gbm->width == 0 || gbm->height == 0) return {};
+
+    Bitmap bitmap(gbm->width, gbm->height);
+    for (auto i = 0; i < 16; i++) {
+        bitmap.SetPaletteEntry(i, {gbm->palette[i].r, gbm->palette[i].g, gbm->palette[i].b});
+    }
+
+    for (auto y = 0; y < gbm->height; y++) {
+        for (auto x = 0; x < gbm->width; x++) {
+            auto pv = gbm->data[y * gbm->width + x];
+            bitmap.SetPixel(x, y, pv);
+        }
+    }
+
+    return bitmap;
+}
+
+Bitmap Gbm::loadFromFile(const char *path) {
+    void *data;
+    auto len = Files::allocateBufferAndLoadFromFile(path, &data);
+    auto bitmap = loadFromMemory(data, len);
+    Files::deleteBuffer(data);
+
+    return bitmap;
+}
+
+void Gbm::writeToFile(const char *path, const Bitmap &bitmap) {
+    auto fp = fopen(path, "wb");
+    if (!fp) return;
+
+    // Write signature
+    uint32_t signature = GBM_SIGNATURE;
+    fwrite(&signature, 4, 1, fp);
+    uint16_t width = bitmap.GetWidth(), height = bitmap.GetHeight();
+    fwrite(&width, 2, 1, fp);
+    fwrite(&height, 2, 1, fp);
+    for (auto i = 0; i < 16; i++) {
+        auto entry = bitmap.GetPaletteEntry(i);
+        auto r = entry.r, g = entry.g, b = entry.b;
+        fwrite(&r, 1, 1, fp);
+        fwrite(&g, 1, 1, fp);
+        fwrite(&b, 1, 1, fp);
+    }
+
+    for (auto y = 0; y < height; y++) {
+        for (auto x = 0; x < width; x++) {
+            auto pv = bitmap.GetPixel(x, y);
+            fwrite(&pv, 1, 1, fp);
+        }
+    }
+
+    fclose(fp);
+}

util/Gbm.h

@@ -0,0 +1,28 @@
+#ifndef GAME_GBM_H
+#define GAME_GBM_H
+
+#include <cstddef>
+
+#include "../graphics/Bitmap.h"
+
+namespace Gbm {
+    struct GbmHeader {
+        uint32_t signature;
+        uint16_t width;
+        uint16_t height;
+        struct {
+            uint8_t r;
+            uint8_t g;
+            uint8_t b;
+        } __attribute__((__packed__)) palette[16];
+        uint8_t data[0];
+    } __attribute__((__packed__));
+
+    Bitmap loadFromMemory(const void *data, size_t size);
+    Bitmap loadFromFile(const char *path);
+
+    void writeToFile(const char *path, const Bitmap &bitmap);
+};
+
+
+#endif //GAME_GBM_H

util/Log.cpp

@@ -0,0 +1,22 @@
+#include "Log.h"
+
+#include <cstdarg>
+
+Log DefaultLog("log.txt");
+
+Log::Log(const char *path) {
+    fp = fopen(path, "w");
+}
+
+Log::~Log() {
+    fclose(fp);
+}
+
+void Log::log(const char *fmt, ...) {
+    va_list args;
+    va_start(args, fmt);
+    vfprintf(fp, fmt, args);
+    va_end(args);
+
+    fflush(fp);
+}

util/Log.h

@@ -0,0 +1,19 @@
+#ifndef GAME_LOG_H
+#define GAME_LOG_H
+#include <cstdio>
+
+class Log {
+public:
+    Log(const char *path);
+    ~Log();
+
+    void log(const char *fmt, ...);
+
+private:
+    FILE *fp;
+};
+
+extern Log DefaultLog;
+
+
+#endif //GAME_LOG_H