all repos — mgba @ 8750f78808736560c24cc662d5a570b81e64b6e0

mGBA Game Boy Advance Emulator

GB: Implement sprites, SRAM
Jeffrey Pfau jeffrey@endrift.com
Thu, 21 Jan 2016 19:30:51 -0800
commit

8750f78808736560c24cc662d5a570b81e64b6e0

parent

5cd84799bec7ad1593b859ecf5ab8f383da581fa

6 files changed, 210 insertions(+), 16 deletions(-)

jump to
M src/gb/memory.c → src/gb/memory.c 
@@ -57,6 +57,9 @@ mappedMemoryFree(gb->memory.wram, GB_SIZE_WORKING_RAM);
 	if (gb->memory.rom) {
 		mappedMemoryFree(gb->memory.rom, gb->memory.romSize);
 	}
+	if (gb->memory.sram) {
+		mappedMemoryFree(gb->memory.sram, 0x8000);
+	}
 }
 
 void GBMemoryReset(struct GB* gb) {

@@ -67,6 +70,10 @@ gb->memory.wram = anonymousMemoryMap(GB_SIZE_WORKING_RAM);
 	gb->memory.wramBank = &gb->memory.wram[GB_SIZE_WORKING_RAM_BANK0];
 	gb->memory.romBank = &gb->memory.rom[GB_SIZE_CART_BANK0];
 	gb->memory.currentBank = 1;
+	gb->memory.sram = anonymousMemoryMap(0x8000); // TODO: Persist
+	gb->memory.sramCurrentBank = 0;
+
+	memset(&gb->video.oam, 0, sizeof(gb->video.oam));
 
 	const struct GBCartridge* cart = &gb->memory.rom[0x100];
 	switch (cart->type) {

@@ -138,8 +145,10 @@ case GB_REGION_VRAM + 1:
 		return gb->video.vram[address & (GB_SIZE_VRAM - 1)];
 	case GB_REGION_EXTERNAL_RAM:
 	case GB_REGION_EXTERNAL_RAM + 1:
-		// TODO
-		return 0;
+		if (memory->sramAccess) {
+			return gb->memory.sramBank[address & (GB_SIZE_EXTERNAL_RAM - 1)];
+		}
+		return 0xFF;
 	case GB_REGION_WORKING_RAM_BANK0:
 	case GB_REGION_WORKING_RAM_BANK0 + 2:
 		return memory->wram[address & (GB_SIZE_WORKING_RAM_BANK0 - 1)];

@@ -149,9 +158,14 @@ default:
 		if (address < GB_BASE_OAM) {
 			return memory->wramBank[address & (GB_SIZE_WORKING_RAM_BANK0 - 1)];
 		}
+		if (address < GB_BASE_UNUSABLE) {
+			if (gb->video.mode < 2) {
+				return gb->video.oam.raw[address & 0xFF];
+			}
+			return 0xFF;
+		}
 		if (address < GB_BASE_IO) {
-			// TODO
-			return 0;
+			return 0xFF;
 		}
 		if (address < GB_BASE_HRAM) {
 			return GBIORead(gb, address & (GB_SIZE_IO - 1));

@@ -185,7 +199,9 @@ gb->video.renderer->writeVRAM(gb->video.renderer, address & (GB_SIZE_VRAM - 1));
 		return;
 	case GB_REGION_EXTERNAL_RAM:
 	case GB_REGION_EXTERNAL_RAM + 1:
-		// TODO
+		if (memory->sramAccess) {
+			gb->memory.sramBank[address & (GB_SIZE_EXTERNAL_RAM - 1)] = value;
+		}
 		return;
 	case GB_REGION_WORKING_RAM_BANK0:
 	case GB_REGION_WORKING_RAM_BANK0 + 2:

@@ -197,8 +213,13 @@ return;
 	default:
 		if (address < GB_BASE_OAM) {
 			memory->wramBank[address & (GB_SIZE_WORKING_RAM_BANK0 - 1)] = value;
+		} else if (address < GB_BASE_UNUSABLE) {
+			if (gb->video.mode < 2) {
+				gb->video.oam.raw[address & 0xFF] = value;
+				gb->video.renderer->writeOAM(gb->video.renderer, address & 0xFF);
+			}
 		} else if (address < GB_BASE_IO) {
-			// TODO
+			// TODO: Log
 		} else if (address < GB_BASE_HRAM) {
 			GBIOWrite(gb, address & (GB_SIZE_IO - 1), value);
 		} else if (address < GB_BASE_IE) {

@@ -282,11 +303,29 @@ memory->romBank = &memory->rom[bankStart];
 	memory->currentBank = bank;
 }
 
+static void _switchSramBank(struct GBMemory* memory, int bank) {
+	size_t bankStart = bank * GB_SIZE_EXTERNAL_RAM;
+	memory->sramBank = &memory->sram[bankStart];
+	memory->sramCurrentBank = bank;
+}
+
 void _GBMBC1(struct GBMemory* memory, uint16_t address, uint8_t value) {
 	int bank = value & 0x1F;
 	switch (address >> 13) {
 	case 0x0:
-		// TODO
+		switch (value) {
+		case 0:
+			memory->sramAccess = false;
+			break;
+		case 0xA:
+			memory->sramAccess = true;
+			_switchSramBank(memory, memory->sramCurrentBank);
+			break;
+		default:
+			// TODO
+			break;
+		}
+		break;
 		break;
 	case 0x1:
 		if (!bank) {

@@ -305,7 +344,18 @@ void _GBMBC3(struct GBMemory* memory, uint16_t address, uint8_t value) {
 	int bank = value & 0x7F;
 	switch (address >> 13) {
 	case 0x0:
-		// TODO
+		switch (value) {
+		case 0:
+			memory->sramAccess = false;
+			break;
+		case 0xA:
+			memory->sramAccess = true;
+			_switchSramBank(memory, memory->sramCurrentBank);
+			break;
+		default:
+			// TODO
+			break;
+		}
 		break;
 	case 0x1:
 		if (!bank) {

@@ -313,6 +363,11 @@ ++bank;
 		}
 		_switchBank(memory, bank);
 		break;
+	case 0x2:
+		if (value < 4) {
+			_switchSramBank(memory, value);
+		}
+		break;
 	}
 }
 

@@ -324,7 +379,19 @@ void _GBMBC5(struct GBMemory* memory, uint16_t address, uint8_t value) {
 	int bank = value & 0x7F;
 	switch (address >> 13) {
 	case 0x0:
-		// TODO
+		switch (value) {
+		case 0:
+			memory->sramAccess = false;
+			break;
+		case 0xA:
+			memory->sramAccess = true;
+			_switchSramBank(memory, memory->sramCurrentBank);
+			break;
+		default:
+			// TODO
+			break;
+		}
+		break;
 		break;
 	case 0x1:
 		_switchBank(memory, bank);
M src/gb/memory.h → src/gb/memory.h 
@@ -20,6 +20,7 @@ GB_BASE_EXTERNAL_RAM = 0xA000,
 	GB_BASE_WORKING_RAM_BANK0 = 0xC000,
 	GB_BASE_WORKING_RAM_BANK1 = 0xD000,
 	GB_BASE_OAM = 0xFE00,
+	GB_BASE_UNUSABLE = 0xFEA0,
 	GB_BASE_IO = 0xFF00,
 	GB_BASE_HRAM = 0xFF80,
 	GB_BASE_IE = 0xFFFF
M src/gb/renderers/software.c → src/gb/renderers/software.c 
@@ -12,6 +12,7 @@ static void GBVideoSoftwareRendererInit(struct GBVideoRenderer* renderer);
 static void GBVideoSoftwareRendererDeinit(struct GBVideoRenderer* renderer);
 static void GBVideoSoftwareRendererReset(struct GBVideoRenderer* renderer);
 static void GBVideoSoftwareRendererWriteVRAM(struct GBVideoRenderer* renderer, uint16_t address);
+static void GBVideoSoftwareRendererWriteOAM(struct GBVideoRenderer* renderer, uint8_t oam);
 static uint8_t GBVideoSoftwareRendererWriteVideoRegister(struct GBVideoRenderer* renderer, uint16_t address, uint8_t value);
 static void GBVideoSoftwareRendererDrawScanline(struct GBVideoRenderer* renderer, int y);
 static void GBVideoSoftwareRendererFinishFrame(struct GBVideoRenderer* renderer);

@@ -19,6 +20,9 @@ static void GBVideoSoftwareRendererGetPixels(struct GBVideoRenderer* renderer, unsigned* stride, const void** pixels);
 static void GBVideoSoftwareRendererPutPixels(struct GBVideoRenderer* renderer, unsigned stride, void* pixels);
 
 static void GBVideoSoftwareRendererDrawBackground(struct GBVideoSoftwareRenderer* renderer, uint8_t* maps, int x, int y, int sx, int sy);
+static void GBVideoSoftwareRendererDrawObj(struct GBVideoSoftwareRenderer* renderer, struct GBObj* obj, int y);
+
+static void _cleanOAM(struct GBVideoSoftwareRenderer* renderer);
 
 #ifdef COLOR_16_BIT
 #ifdef COLOR_5_6_5

@@ -36,6 +40,7 @@ renderer->d.reset = GBVideoSoftwareRendererReset;
 	renderer->d.deinit = GBVideoSoftwareRendererDeinit;
 	renderer->d.writeVideoRegister = GBVideoSoftwareRendererWriteVideoRegister;
 	renderer->d.writeVRAM = GBVideoSoftwareRendererWriteVRAM;
+	renderer->d.writeOAM = GBVideoSoftwareRendererWriteOAM;
 	renderer->d.drawScanline = GBVideoSoftwareRendererDrawScanline;
 	renderer->d.finishFrame = GBVideoSoftwareRendererFinishFrame;
 	renderer->d.getPixels = 0;

@@ -65,6 +70,8 @@ softwareRenderer->scy = 0;
 	softwareRenderer->scx = 0;
 	softwareRenderer->wy = 0;
 	softwareRenderer->wx = 0;
+	softwareRenderer->oamMax = 0;
+	softwareRenderer->oamDirty = false;
 }
 
 static void GBVideoSoftwareRendererDeinit(struct GBVideoRenderer* renderer) {

@@ -76,6 +83,13 @@ static void GBVideoSoftwareRendererWriteVRAM(struct GBVideoRenderer* renderer, uint16_t address) {
 	struct GBVideoSoftwareRenderer* softwareRenderer = (struct GBVideoSoftwareRenderer*) renderer;
 	// TODO
 }
+
+static void GBVideoSoftwareRendererWriteOAM(struct GBVideoRenderer* renderer, uint8_t oam) {
+	struct GBVideoSoftwareRenderer* softwareRenderer = (struct GBVideoSoftwareRenderer*) renderer;
+	UNUSED(oam);
+	softwareRenderer->oamDirty = true;
+}
+
 static uint8_t GBVideoSoftwareRendererWriteVideoRegister(struct GBVideoRenderer* renderer, uint16_t address, uint8_t value) {
 	struct GBVideoSoftwareRenderer* softwareRenderer = (struct GBVideoSoftwareRenderer*) renderer;
 	switch (address) {

@@ -119,7 +133,14 @@
 static void GBVideoSoftwareRendererDrawScanline(struct GBVideoRenderer* renderer, int y) {
 	struct GBVideoSoftwareRenderer* softwareRenderer = (struct GBVideoSoftwareRenderer*) renderer;
 
-	color_t* row = &softwareRenderer->outputBuffer[softwareRenderer->outputBufferStride * y];
+	size_t x;
+	for (x = 0; x < GB_VIDEO_HORIZONTAL_PIXELS; ++x) {
+		softwareRenderer->row[x] = GB_PALETTE[0];
+	}
+
+	if (softwareRenderer->oamDirty) {
+		_cleanOAM(softwareRenderer);
+	}
 
 	uint8_t* maps = &softwareRenderer->d.vram[GB_BASE_MAP];
 	if (GBRegisterLCDCIsTileMap(softwareRenderer->lcdc)) {

@@ -127,15 +148,27 @@ maps += GB_SIZE_MAP;
 	}
 	GBVideoSoftwareRendererDrawBackground(softwareRenderer, maps, 0, y, softwareRenderer->scx, softwareRenderer->scy);
 
-	if (GBRegisterLCDCIsWindow(softwareRenderer->lcdc)) {
+	if (GBRegisterLCDCIsWindow(softwareRenderer->lcdc) && softwareRenderer->wy < GB_VIDEO_VERTICAL_PIXELS) {
 		maps = &softwareRenderer->d.vram[GB_BASE_MAP];
 		if (GBRegisterLCDCIsWindowTileMap(softwareRenderer->lcdc)) {
 			maps += GB_SIZE_MAP;
 		}
-		GBVideoSoftwareRendererDrawBackground(softwareRenderer, maps, -7, y, softwareRenderer->wx - 7, softwareRenderer->wy);
+		GBVideoSoftwareRendererDrawBackground(softwareRenderer, maps, 0, y, 7 - softwareRenderer->wx, -softwareRenderer->wy);
 	}
 
-	size_t x;
+	int spriteHeight = 8;
+	if (GBRegisterLCDCIsObjSize(softwareRenderer->lcdc)) {
+		spriteHeight = 16;
+	}
+	int i;
+	for (i = 0; i < softwareRenderer->oamMax; ++i) {
+		// TODO: Sprite sizes
+		if (y >= softwareRenderer->obj[i]->y - 16 && y < softwareRenderer->obj[i]->y - 16 + spriteHeight) {
+			GBVideoSoftwareRendererDrawObj(softwareRenderer, softwareRenderer->obj[i], y);
+		}
+	}
+
+	color_t* row = &softwareRenderer->outputBuffer[softwareRenderer->outputBufferStride * y];
 #ifdef COLOR_16_BIT
 #if defined(__ARM_NEON) && !defined(__APPLE__)
 	_to16Bit(row, softwareRenderer->row, GB_VIDEO_HORIZONTAL_PIXELS);

@@ -149,6 +182,24 @@ memcpy(row, softwareRenderer->row, GB_VIDEO_HORIZONTAL_PIXELS * sizeof(*row));
 #endif
 }
 
+static void _cleanOAM(struct GBVideoSoftwareRenderer* renderer) {
+	// TODO: GBC differences
+	renderer->oamMax = 0;
+	int o = 0;
+	int i;
+	for (i = 0; i < 40; ++i) {
+		uint8_t y = renderer->d.oam->obj[i].y;
+		if (y < 16 || y >= GB_VIDEO_VERTICAL_PIXELS + 16) {
+			continue;
+		}
+		// TODO: Sort
+		renderer->obj[o] = &renderer->d.oam->obj[i];
+		++o;
+	}
+	renderer->oamMax = o;
+	renderer->oamDirty = false;
+}
+
 static void GBVideoSoftwareRendererFinishFrame(struct GBVideoRenderer* renderer) {
 	struct GBVideoSoftwareRenderer* softwareRenderer = (struct GBVideoSoftwareRenderer*) renderer;
 

@@ -165,9 +216,6 @@ data += 0x1000;
 	}
 	int topY = (((y + sy) >> 3) & 0x1F) * 0x20;
 	int bottomY = (y + sy) & 7;
-	if (x < 0) {
-		x = 0;
-	}
 	for (; x < GB_VIDEO_HORIZONTAL_PIXELS; ++x) {
 		int topX = ((x + sx) >> 3) & 0x1F;
 		int bottomX = 7 - ((x + sx) & 7);

@@ -184,3 +232,45 @@ tileDataLower >>= bottomX;
 		renderer->row[x] = renderer->bgPalette[((tileDataUpper & 1) << 1) | (tileDataLower & 1)];
 	}
 }
+
+static void GBVideoSoftwareRendererDrawObj(struct GBVideoSoftwareRenderer* renderer, struct GBObj* obj, int y) {
+	uint8_t* data = renderer->d.vram;
+	int tileOffset = 0;
+	int bottomY;
+	if (GBObjAttributesIsYFlip(obj->attr)) {
+		bottomY = 7 - ((y - obj->y - 16) & 7);
+		if (y - obj->y < -8) {
+			++tileOffset;
+		}
+	} else {
+		bottomY = (y - obj->y - 16) & 7;
+		if (y - obj->y >= -8) {
+			++tileOffset;
+		}
+	}
+	int end = GB_VIDEO_HORIZONTAL_PIXELS;
+	if (obj->x < end) {
+		end = obj->x;
+	}
+	int x = obj->x - 8;
+	if (x < 0) {
+		x = 0;
+	}
+	for (; x < end; ++x) {
+		int bottomX;
+		if (GBObjAttributesIsXFlip(obj->attr)) {
+			bottomX = (x - obj->x) & 7;
+		} else {
+			bottomX = 7 - ((x - obj->x) & 7);
+		}
+		int objTile = obj->tile + tileOffset;
+		uint8_t tileDataLower = data[(objTile * 8 + bottomY) * 2];
+		uint8_t tileDataUpper = data[(objTile * 8 + bottomY) * 2 + 1];
+		tileDataUpper >>= bottomX;
+		tileDataLower >>= bottomX;
+		color_t current = renderer->row[x];
+		if (((tileDataUpper | tileDataLower) & 1) && (!GBObjAttributesIsPriority(obj->attr) || current == GB_PALETTE[0])) {
+			renderer->row[x] = renderer->bgPalette[((tileDataUpper & 1) << 1) | (tileDataLower & 1)];
+		}
+	}
+}
M src/gb/renderers/software.h → src/gb/renderers/software.h 
@@ -35,6 +35,10 @@ uint8_t wy;
 	uint8_t wx;
 
 	GBRegisterLCDC lcdc;
+
+	struct GBObj* obj[40];
+	int oamMax;
+	bool oamDirty;
 };
 
 void GBVideoSoftwareRendererCreate(struct GBVideoSoftwareRenderer*);
M src/gb/video.c → src/gb/video.c 
@@ -15,6 +15,7 @@ static void GBVideoDummyRendererReset(struct GBVideoRenderer* renderer);
 static void GBVideoDummyRendererDeinit(struct GBVideoRenderer* renderer);
 static uint8_t GBVideoDummyRendererWriteVideoRegister(struct GBVideoRenderer* renderer, uint16_t address, uint8_t value);
 static void GBVideoDummyRendererWriteVRAM(struct GBVideoRenderer* renderer, uint16_t address);
+static void GBVideoDummyRendererWriteOAM(struct GBVideoRenderer* renderer, uint8_t oam);
 static void GBVideoDummyRendererDrawScanline(struct GBVideoRenderer* renderer, int y);
 static void GBVideoDummyRendererFinishFrame(struct GBVideoRenderer* renderer);
 static void GBVideoDummyRendererGetPixels(struct GBVideoRenderer* renderer, unsigned* stride, const void** pixels);

@@ -25,6 +26,7 @@ .reset = GBVideoDummyRendererReset,
 	.deinit = GBVideoDummyRendererDeinit,
 	.writeVideoRegister = GBVideoDummyRendererWriteVideoRegister,
 	.writeVRAM = GBVideoDummyRendererWriteVRAM,
+	.writeOAM = GBVideoDummyRendererWriteOAM,
 	.drawScanline = GBVideoDummyRendererDrawScanline,
 	.finishFrame = GBVideoDummyRendererFinishFrame,
 	.getPixels = GBVideoDummyRendererGetPixels

@@ -53,6 +55,8 @@ mappedMemoryFree(video->vram, GB_SIZE_VRAM);
 	}
 	video->vram = anonymousMemoryMap(GB_SIZE_VRAM);
 	video->renderer->vram = video->vram;
+	memset(&video->oam, 0, sizeof(video->oam));
+	video->renderer->oam = &video->oam;
 
 	video->renderer->deinit(video->renderer);
 	video->renderer->init(video->renderer);

@@ -197,6 +201,12 @@
 static void GBVideoDummyRendererWriteVRAM(struct GBVideoRenderer* renderer, uint16_t address) {
 	UNUSED(renderer);
 	UNUSED(address);
+	// Nothing to do
+}
+
+static void GBVideoDummyRendererWriteOAM(struct GBVideoRenderer* renderer, uint8_t oam) {
+	UNUSED(renderer);
+	UNUSED(oam);
 	// Nothing to do
 }
M src/gb/video.h → src/gb/video.h 
@@ -29,6 +29,24 @@ GB_BASE_MAP = 0x1800,
 	GB_SIZE_MAP = 0x0400
 };
 
+DECL_BITFIELD(GBObjAttributes, uint8_t);
+DECL_BIT(GBObjAttributes, Palette, 4);
+DECL_BIT(GBObjAttributes, XFlip, 5);
+DECL_BIT(GBObjAttributes, YFlip, 6);
+DECL_BIT(GBObjAttributes, Priority, 7);
+
+struct GBObj {
+	uint8_t y;
+	uint8_t x;
+	uint8_t tile;
+	GBObjAttributes attr;
+};
+
+union GBOAM {
+	struct GBObj obj[40];
+	uint8_t raw[160];
+};
+
 struct GBVideoRenderer {
 	void (*init)(struct GBVideoRenderer* renderer);
 	void (*reset)(struct GBVideoRenderer* renderer);

@@ -36,6 +54,7 @@ void (*deinit)(struct GBVideoRenderer* renderer);
 
 	uint8_t (*writeVideoRegister)(struct GBVideoRenderer* renderer, uint16_t address, uint8_t value);
 	void (*writeVRAM)(struct GBVideoRenderer* renderer, uint16_t address);
+	void (*writeOAM)(struct GBVideoRenderer* renderer, uint8_t oam);
 	void (*drawScanline)(struct GBVideoRenderer* renderer, int y);
 	void (*finishFrame)(struct GBVideoRenderer* renderer);
 

@@ -43,6 +62,7 @@ void (*getPixels)(struct GBVideoRenderer* renderer, unsigned* stride, const void** pixels);
 	void (*putPixels)(struct GBVideoRenderer* renderer, unsigned stride, void* pixels);
 
 	uint8_t* vram;
+	union GBOAM* oam;
 };
 
 DECL_BITFIELD(GBRegisterLCDC, uint8_t);

@@ -79,6 +99,8 @@ int32_t nextMode;
 
 	uint8_t* vram;
 	uint8_t* vramBank;
+
+	union GBOAM oam;
 
 	int32_t frameCounter;
 	int frameskip;