DS GX: Clear depth

CHANGES

@@ -1,6 +1,7 @@
 medusa alpha 3 (Future)
 Features:
  - DS GX: Toon shading
+ - DS GX: Clear depth
 Bugfixes:
  - DS GX: Fix vertex texture transformation (fixes mgba.io/i/702)
  - DS GX: Automatically normalize winding culling calculations (fixes mgba.io/i/699)

README.md

@@ -182,7 +182,6 @@ Missing features on DS are
 	- Edge marking/wireframe
 	- Highlight shading
 	- Fog
-	- Clear depth
 	- Anti-aliasing
 	- Alpha test
 	- Position test

include/mgba/internal/ds/gx/software.h

@@ -95,6 +95,7 @@ struct DSGXSoftwareRenderer {
 	int sort;
 	uint16_t clearStencil;
 	color_t clearColor;
+	uint32_t clearDepth;
 	bool flushPending;
 
 	struct DSGXVertex* verts;

src/ds/gx.c

@@ -1326,6 +1326,7 @@ void DSGXReset(struct DSGX* gx) {
 	gx->currentPoly.polyParams = 0x001F00C0;
 	gx->nextPoly.polyParams = 0x001F00C0;
 	gx->dmaSource = -1;
+	gx->renderer->reset(gx->renderer);
 }
 
 void DSGXAssociateRenderer(struct DSGX* gx, struct DSGXRenderer* renderer) {

src/ds/gx/software.c

@@ -440,6 +440,7 @@ static void DSGXSoftwareRendererReset(struct DSGXRenderer* renderer) {
 	struct DSGXSoftwareRenderer* softwareRenderer = (struct DSGXSoftwareRenderer*) renderer;
 	softwareRenderer->clearColor = 0;
 	softwareRenderer->clearStencil = 0;
+	softwareRenderer->clearDepth = 0xFFFFFF;
 }
 
 static void DSGXSoftwareRendererDeinit(struct DSGXRenderer* renderer) {
@@ -738,12 +739,13 @@ static void DSGXSoftwareRendererSetRAM(struct DSGXRenderer* renderer, struct DSG
 
 	color_t clearColor = softwareRenderer->clearColor;
 	uint16_t clearStencil = softwareRenderer->clearStencil;
+	uint32_t clearDepth = softwareRenderer->clearDepth;
 
 	for (i = 0; i < DS_VIDEO_VERTICAL_PIXELS * DS_VIDEO_HORIZONTAL_PIXELS ; i += 4) {
-		softwareRenderer->depthBuffer[i] = INT32_MAX;
-		softwareRenderer->depthBuffer[i + 1] = INT32_MAX;
-		softwareRenderer->depthBuffer[i + 2] = INT32_MAX;
-		softwareRenderer->depthBuffer[i + 3] = INT32_MAX;
+		softwareRenderer->depthBuffer[i] = clearDepth;
+		softwareRenderer->depthBuffer[i + 1] = clearDepth;
+		softwareRenderer->depthBuffer[i + 2] = clearDepth;
+		softwareRenderer->depthBuffer[i + 3] = clearDepth;
 		softwareRenderer->scanlineCache[i] = clearColor;
 		softwareRenderer->scanlineCache[i + 1] = clearColor;
 		softwareRenderer->scanlineCache[i + 2] = clearColor;
@@ -816,5 +818,8 @@ static void DSGXSoftwareRendererWriteRegister(struct DSGXRenderer* renderer, uin
 		softwareRenderer->clearColor |= (value & 0x001F) << 27;
 		softwareRenderer->clearStencil = (value & 0x3F00) >> 8;
 		break;
+	case DS9_REG_CLEAR_DEPTH:
+		softwareRenderer->clearDepth = (value & 0x7FFF) * 0x200 + 0x1FF;
+		break;
 	}
 }