From 1f0b1d33e2c2171ca2642bef9f0d2421c194bb46 Mon Sep 17 00:00:00 2001
From: UnknownShadow200 <unknownshadow200@gmail.com>
Date: Tue, 16 Jul 2024 18:06:28 +1000
Subject: [PATCH] 3DS: Avoid clearing bottom screen for a little better
 performance, and don't pointlessly allocate a depth buffer for it

---
 src/Graphics_3DS.c    | 12 ++++++++----
 third_party/citro3d.c | 43 ++++++++++++++++++++++++-------------------
 2 files changed, 32 insertions(+), 23 deletions(-)

diff --git a/src/Graphics_3DS.c b/src/Graphics_3DS.c
index 99f1d0dc6..45cf4c1e5 100644
--- a/src/Graphics_3DS.c
+++ b/src/Graphics_3DS.c
@@ -149,12 +149,15 @@ static void InitCitro3D(void) {
 	C3D_Init(C3D_DEFAULT_CMDBUF_SIZE * 4);
 	aptHook(&hookCookie, AptEventHook, NULL);
 
-	C3D_RenderTargetCreate(&topTargetLeft, 240, 400, GPU_RB_RGBA8, GPU_RB_DEPTH24);
+	C3D_RenderTargetInit(&topTargetLeft,  240, 400);
+	C3D_RenderTargetColor(&topTargetLeft, GPU_RB_RGBA8);
+	C3D_RenderTargetDepth(&topTargetLeft, GPU_RB_DEPTH24);
 	C3D_RenderTargetSetOutput(&topTargetLeft, GFX_TOP, GFX_LEFT, DISPLAY_TRANSFER_FLAGS);
 
 	// Even though the bottom screen is 320 pixels wide, we use 400 here so that the same ortho matrix
 	// can be used for both screens. The output is clipped to the actual screen width, anyway.
-	C3D_RenderTargetCreate(&bottomTarget, 240, 400, GPU_RB_RGBA8, GPU_RB_DEPTH24);
+	C3D_RenderTargetInit(&bottomTarget, 240, 400);
+	C3D_RenderTargetColor(&bottomTarget, GPU_RB_RGBA8);
 	C3D_RenderTargetSetOutput(&bottomTarget, GFX_BOTTOM, GFX_LEFT, DISPLAY_TRANSFER_FLAGS);
 
 	gfxSetDoubleBuffering(GFX_TOP, true);
@@ -237,7 +240,9 @@ void Gfx_Set3DRight(struct Matrix* proj, struct Matrix* view) {
 	Calc3DProjection(+1, proj);
 
 	if (!createdTopTargetRight) {
-		C3D_RenderTargetCreate(&topTargetRight, 240, 400, GPU_RB_RGBA8, GPU_RB_DEPTH24);
+		C3D_RenderTargetInit(&topTargetRight,  240, 400);
+		C3D_RenderTargetColor(&topTargetRight, GPU_RB_RGBA8);
+		C3D_RenderTargetDepth(&topTargetRight, GPU_RB_DEPTH24);
 		C3D_RenderTargetSetOutput(&topTargetRight, GFX_TOP, GFX_RIGHT, DISPLAY_TRANSFER_FLAGS);
 		createdTopTargetRight = true;
 	}
@@ -569,7 +574,6 @@ void Gfx_ClearBuffers(GfxBuffers buffers) {
 	if (buffers & GFX_BUFFER_DEPTH) targets |= C3D_CLEAR_DEPTH;
 	
 	C3D_RenderTargetClear(&topTargetLeft, targets, clear_color, 0);
-	C3D_RenderTargetClear(&bottomTarget,  targets,           0, 0);
 }
 
 void Gfx_EndFrame(void) {
diff --git a/third_party/citro3d.c b/third_party/citro3d.c
index 6ff2908bc..d747dc83e 100644
--- a/third_party/citro3d.c
+++ b/third_party/citro3d.c
@@ -332,7 +332,6 @@ static bool C3D_FrameDrawOn(C3D_RenderTarget* target);
 static void C3D_FrameSplit(u8 flags);
 static void C3D_FrameEnd(u8 flags);
 
-static void C3D_RenderTargetCreate(C3D_RenderTarget* target, int width, int height, GPU_COLORBUF colorFmt, GPU_DEPTHBUF depthFmt);
 static void C3D_RenderTargetDelete(C3D_RenderTarget* target);
 static void C3D_RenderTargetSetOutput(C3D_RenderTarget* target, gfxScreen_t screen, gfx3dSide_t side, u32 transferFlags);
 
@@ -1143,30 +1142,36 @@ static void C3D_FrameEnd(u8 flags)
 	gxCmdQueueRun(&ctx->gxQueue);
 }
 
-void C3D_RenderTargetCreate(C3D_RenderTarget* target, int width, int height, GPU_COLORBUF colorFmt, GPU_DEPTHBUF depthFmt)
+static void C3D_RenderTargetInit(C3D_RenderTarget* target, int width, int height)
 {
-	size_t colorSize = C3D_CalcColorBufSize(width,height,colorFmt);
-	size_t depthSize = C3D_CalcDepthBufSize(width,height,depthFmt);
 	memset(target, 0, sizeof(C3D_RenderTarget));
 
-	void* depthBuf = NULL;
-	void* colorBuf = vramAlloc(colorSize);
-	if (!colorBuf) goto _fail;
-
-	vramAllocPos vramBank = addrGetVRAMBank(colorBuf);
-	depthBuf = vramAllocAt(depthSize, vramBank ^ VRAM_ALLOC_ANY); // Attempt opposite bank first...
-	if (!depthBuf) depthBuf = vramAllocAt(depthSize, vramBank); // ... if that fails, attempt same bank
-	if (!depthBuf) goto _fail;
-
 	C3D_FrameBuf* fb = &target->frameBuf;
 	C3D_FrameBufAttrib(fb, width, height, false);
-	C3D_FrameBufColor(fb, colorBuf, colorFmt);
-	C3D_FrameBufDepth(fb, depthBuf, depthFmt);
-	return;
+}
 
-_fail:
-	if (depthBuf) vramFree(depthBuf);
-	if (colorBuf) vramFree(colorBuf);
+static void C3D_RenderTargetColor(C3D_RenderTarget* target, GPU_COLORBUF colorFmt)
+{
+	C3D_FrameBuf* fb = &target->frameBuf;
+	size_t colorSize = C3D_CalcColorBufSize(fb->width, fb->height, colorFmt);
+	void* colorBuf   = vramAlloc(colorSize);
+
+	if (!colorBuf) return;
+	C3D_FrameBufColor(fb, colorBuf, colorFmt);
+}
+
+static void C3D_RenderTargetDepth(C3D_RenderTarget* target, GPU_DEPTHBUF depthFmt)
+{
+	C3D_FrameBuf* fb = &target->frameBuf;
+	size_t depthSize = C3D_CalcDepthBufSize(fb->width, fb->height, depthFmt);
+	void* depthBuf   = NULL;
+
+	vramAllocPos vramBank = addrGetVRAMBank(fb->colorBuf);
+	depthBuf = vramAllocAt(depthSize, vramBank ^ VRAM_ALLOC_ANY); // Attempt opposite bank first...
+	if (!depthBuf) depthBuf = vramAllocAt(depthSize, vramBank); // ... if that fails, attempt same bank
+	if (!depthBuf) return;
+
+	C3D_FrameBufDepth(fb, depthBuf, depthFmt);
 }
 
 static void C3Di_RenderTargetDestroy(C3D_RenderTarget* target)