GBA Video: Simplify sprite cycle counting (fixes #1279)

CHANGES

@@ -27,6 +27,7 @@ Emulation fixes:
  - GBA Video: Fix disabling OBJWIN in GL renderer (fixes mgba.io/i/1759)
  - GBA Video: Add missing parts of 256-color mode 0 mosaic (fixes mgba.io/i/1701)
  - GBA Video: Fix double-size OBJ wrapping in GL renderer (fixes mgba.io/i/1712)
+ - GBA Video: Simplify sprite cycle counting (fixes mgba.io/i/1279)
  - SM83: Emulate HALT bug
 Other fixes:
  - 3DS: Fix framelimiter on newer citro3d (fixes mgba.io/i/1771)

include/mgba/internal/gba/renderers/common.h

@@ -16,6 +16,7 @@ struct GBAVideoRendererSprite {
 	struct GBAObj obj;
 	int16_t y;
 	int16_t endY;
+	int16_t cycles;
 	int8_t index;
 };
 

src/gba/renderers/common.c

@@ -16,14 +16,19 @@ int GBAVideoRendererCleanOAM(struct GBAObj* oam, struct GBAVideoRendererSprite*
 		LOAD_16LE(obj.b, 0, &oam[i].b);
 		LOAD_16LE(obj.c, 0, &oam[i].c);
 		if (GBAObjAttributesAIsTransformed(obj.a) || !GBAObjAttributesAIsDisable(obj.a)) {
+			int width = GBAVideoObjSizes[GBAObjAttributesAGetShape(obj.a) * 4 + GBAObjAttributesBGetSize(obj.b)][0];
 			int height = GBAVideoObjSizes[GBAObjAttributesAGetShape(obj.a) * 4 + GBAObjAttributesBGetSize(obj.b)][1];
+			int cycles = width;
 			if (GBAObjAttributesAIsTransformed(obj.a)) {
 				height <<= GBAObjAttributesAGetDoubleSize(obj.a);
+				width <<= GBAObjAttributesAGetDoubleSize(obj.a);
+				cycles = 10 + width * 2;
 			}
 			if (GBAObjAttributesAGetY(obj.a) < GBA_VIDEO_VERTICAL_PIXELS || GBAObjAttributesAGetY(obj.a) + height >= VIDEO_VERTICAL_TOTAL_PIXELS) {
 				int y = GBAObjAttributesAGetY(obj.a) + offsetY;
 				sprites[oamMax].y = y;
 				sprites[oamMax].endY = y + height;
+				sprites[oamMax].cycles = cycles;
 				sprites[oamMax].obj = obj;
 				sprites[oamMax].index = i;
 				++oamMax;

src/gba/renderers/software-obj.c

@@ -9,7 +9,6 @@
 	SPRITE_YBASE_ ## DEPTH(inY); \
 	unsigned tileData; \
 	for (; outX < condition; ++outX, inX += xOffset) { \
-		renderer->spriteCyclesRemaining -= 1; \
 		SPRITE_XBASE_ ## DEPTH(inX); \
 		SPRITE_DRAW_PIXEL_ ## DEPTH ## _ ## TYPE(inX); \
 	}
@@ -33,7 +32,6 @@
 	unsigned widthMask = ~(width - 1); \
 	unsigned heightMask = ~(height - 1); \
 	for (; outX < condition; ++outX, ++inX) { \
-		renderer->spriteCyclesRemaining -= 2; \
 		xAccum += mat.a; \
 		yAccum += mat.c; \
 		int localX = xAccum >> 8; \
@@ -55,7 +53,6 @@
 	int localX = xAccum >> 8; \
 	int localY = yAccum >> 8; \
 	for (; outX < condition; ++outX, ++inX) { \
-		renderer->spriteCyclesRemaining -= 2; \
 		xAccum += mat.a; \
 		yAccum += mat.c; \
 		\
@@ -272,7 +269,6 @@ int GBAVideoSoftwareRendererPreprocessSprite(struct GBAVideoSoftwareRenderer* re
 		if (outX < start || outX >= condition) {
 			return 0;
 		}
-		renderer->spriteCyclesRemaining -= 10;
 
 		if (!GBAObjAttributesAIs256Color(sprite->a)) {
 			palette = &palette[GBAObjAttributesCGetPalette(sprite->c) << 4];
@@ -306,9 +302,6 @@ int GBAVideoSoftwareRendererPreprocessSprite(struct GBAVideoSoftwareRenderer* re
 				SPRITE_TRANSFORMED_LOOP(256, NORMAL);
 			}
 		}
-		if (end == GBA_VIDEO_HORIZONTAL_PIXELS && x + totalWidth > GBA_VIDEO_HORIZONTAL_PIXELS) {
-			renderer->spriteCyclesRemaining -= (x + totalWidth - GBA_VIDEO_HORIZONTAL_PIXELS) * 2;
-		}
 	} else {
 		int outX = x >= start ? x : start;
 		int condition = x + width;
@@ -366,9 +359,6 @@ int GBAVideoSoftwareRendererPreprocessSprite(struct GBAVideoSoftwareRenderer* re
 				SPRITE_NORMAL_LOOP(256, NORMAL);
 			}
 		}
-		if (end == GBA_VIDEO_HORIZONTAL_PIXELS && x + width > GBA_VIDEO_HORIZONTAL_PIXELS) {
-			renderer->spriteCyclesRemaining -= x + width - GBA_VIDEO_HORIZONTAL_PIXELS;
-		}
 	}
 	return 1;
 }

src/gba/renderers/video-software.c

@@ -845,12 +845,10 @@ static void _drawScanline(struct GBAVideoSoftwareRenderer* renderer, int y) {
 				}
 			}
 			for (w = 0; w < renderer->nWindows; ++w) {
-				if (renderer->spriteCyclesRemaining <= 0) {
-					break;
-				}
 				renderer->currentWindow = renderer->windows[w].control;
 				renderer->start = renderer->end;
 				renderer->end = renderer->windows[w].endX;
+				// TODO: partial sprite drawing
 				if (!GBAWindowControlIsObjEnable(renderer->currentWindow.packed) && !GBARegisterDISPCNTIsObjwinEnable(renderer->dispcnt)) {
 					continue;
 				}
@@ -858,6 +856,7 @@ static void _drawScanline(struct GBAVideoSoftwareRenderer* renderer, int y) {
 				int drawn = GBAVideoSoftwareRendererPreprocessSprite(renderer, &sprite->obj, sprite->index, localY);
 				spriteLayers |= drawn << GBAObjAttributesCGetPriority(sprite->obj.c);
 			}
+			renderer->spriteCyclesRemaining -= sprite->cycles;
 			if (renderer->spriteCyclesRemaining <= 0) {
 				break;
 			}