GBA Video: Fix deferred blending when OBJWIN matches window (fixes #1905

)
mgba-emu · Oct 5, 2020 · 3f10823 · 3f10823
1 parent 830aea2
commit 3f10823
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Showing 2 changed files with 11 additions and 9 deletions.
diff --git a/CHANGES b/CHANGES
@@ -48,6 +48,7 @@ Emulation fixes:
  - GBA Video: Fix rare regression blending semitransparent sprites (fixes mgba.io/i/1876)
  - GBA Video: Emulate sprite cycle limits in OpenGL renderer (fixes mgba.io/i/1635)
  - GBA Video: Do not affect OBJ pixel priority when writing OBJWIN (fixes mgba.io/i/1890)
+ - GBA Video: Fix deferred blending when OBJWIN matches window (fixes mgba.io/i/1905)
  - SM83: Emulate HALT bug
 Other fixes:
  - 3DS: Redo video sync to be more precise

diff --git a/src/gba/renderers/video-software.c b/src/gba/renderers/video-software.c
@@ -644,17 +644,18 @@ static void GBAVideoSoftwareRendererDrawScanline(struct GBAVideoRenderer* render
 	}
 	if (softwareRenderer->forceTarget1 && (softwareRenderer->blendEffect == BLEND_DARKEN || softwareRenderer->blendEffect == BLEND_BRIGHTEN)) {
 		x = 0;
-		uint32_t mask = FLAG_REBLEND | FLAG_IS_BACKGROUND;
-		uint32_t match = FLAG_REBLEND;
-		if (GBARegisterDISPCNTIsObjwinEnable(softwareRenderer->dispcnt)) {
-			mask |= FLAG_OBJWIN;
-			if (GBAWindowControlIsBlendEnable(softwareRenderer->objwin.packed)) {
-				match |= FLAG_OBJWIN;
-			}
-		}
 		for (w = 0; w < softwareRenderer->nWindows; ++w) {
 			int end = softwareRenderer->windows[w].endX;
-			if (!GBAWindowControlIsBlendEnable(softwareRenderer->windows[w].control.packed)) {
+			uint32_t mask = FLAG_REBLEND | FLAG_IS_BACKGROUND;
+			uint32_t match = FLAG_REBLEND;
+			bool objBlend = GBAWindowControlIsBlendEnable(softwareRenderer->objwin.packed);
+			bool winBlend = GBAWindowControlIsBlendEnable(softwareRenderer->windows[w].control.packed);
+			if (GBARegisterDISPCNTIsObjwinEnable(softwareRenderer->dispcnt) && objBlend != winBlend) {
+				mask |= FLAG_OBJWIN;
+				if (objBlend) {
+					match |= FLAG_OBJWIN;
+				}
+			} else if (!winBlend) {
 				x = end;
 				continue;
 			}