From b5723c920939ec9051a0353150a490df940df599 Mon Sep 17 00:00:00 2001
From: fincs <fincs.alt1@gmail.com>
Date: Mon, 8 Dec 2014 15:57:39 +0100
Subject: [PATCH] Add gfxSetDoubleBuffering() for disabling double-buffering

---
 libctru/include/3ds/gfx.h |  1 +
 libctru/source/gfx.c      | 25 +++++++++++++++----------
 2 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/libctru/include/3ds/gfx.h b/libctru/include/3ds/gfx.h
index 2965210..e7b33d3 100644
--- a/libctru/include/3ds/gfx.h
+++ b/libctru/include/3ds/gfx.h
@@ -22,6 +22,7 @@ void gfxExit();
 //control stuff
 void gfxSet3D(bool enable);
 void gfxSetScreenFormat(gfxScreen_t screen, GSP_FramebufferFormats format);
+void gfxSetDoubleBuffering(bool doubleBuffering);
 void gfxFlushBuffers();
 void gfxSwapBuffers();
 void gfxSwapBuffersGpu();
diff --git a/libctru/source/gfx.c b/libctru/source/gfx.c
index 702051b..df99fcc 100644
--- a/libctru/source/gfx.c
+++ b/libctru/source/gfx.c
@@ -12,13 +12,14 @@ u8* gfxTopLeftFramebuffers[2];
 u8* gfxTopRightFramebuffers[2];
 u8* gfxBottomFramebuffers[2];
 
-u8 currentBuffer;
-bool enable3d;
+static u8 currentBuffer;
+static bool enable3d;
+static int doubleBuf = 1;
 
 Handle gspEvent, gspSharedMemHandle;
 
-GSP_FramebufferFormats topFormat = GSP_BGR8_OES;
-GSP_FramebufferFormats botFormat = GSP_BGR8_OES;
+static GSP_FramebufferFormats topFormat = GSP_BGR8_OES;
+static GSP_FramebufferFormats botFormat = GSP_BGR8_OES;
 
 void gfxSet3D(bool enable)
 {
@@ -32,6 +33,10 @@ void gfxSetScreenFormat(gfxScreen_t screen, GSP_FramebufferFormats format) {
         botFormat = format;
 }
 
+void gfxSetDoubleBuffering(bool doubleBuffering) {
+	doubleBuf = doubleBuffering ? 1 : 0; // make sure they're the integer values '1' and '0'
+}
+
 static u32 __get_bytes_per_pixel(GSP_FramebufferFormats format) {
     switch(format) {
     case GSP_RGBA8_OES:
@@ -76,7 +81,7 @@ void gfxWriteFramebufferInfo(gfxScreen_t screen)
 	u8* framebufferInfoHeader=gfxSharedMemory+0x200+gfxThreadID*0x80;
 	if(screen==GFX_BOTTOM)framebufferInfoHeader+=0x40;
 	GSP_FramebufferInfo* framebufferInfo=(GSP_FramebufferInfo*)&framebufferInfoHeader[0x4];
-	framebufferInfoHeader[0x0]^=1;
+	framebufferInfoHeader[0x0]^=doubleBuf;
 	framebufferInfo[framebufferInfoHeader[0x0]]=(screen==GFX_TOP)?(topFramebufferInfo):(bottomFramebufferInfo);
 	framebufferInfoHeader[0x1]=1;
 }
@@ -131,7 +136,7 @@ void gfxExit()
 	// Exit event handler
 	gspExitEventHandler();
 
-	// Free framebuffers (let's pretend linearFree is actually implemented...)
+	// Free framebuffers
 	linearFree(gfxTopRightFramebuffers[1]);
 	linearFree(gfxTopRightFramebuffers[0]);
 	linearFree(gfxBottomFramebuffers[1]);
@@ -159,10 +164,10 @@ u8* gfxGetFramebuffer(gfxScreen_t screen, gfx3dSide_t side, u16* width, u16* hei
 	if(screen==GFX_TOP)
 	{
 		if(height)*height=400;
-		return (side==GFX_LEFT || !enable3d)?(gfxTopLeftFramebuffers[currentBuffer^1]):(gfxTopRightFramebuffers[currentBuffer^1]);
+		return (side==GFX_LEFT || !enable3d)?(gfxTopLeftFramebuffers[currentBuffer^doubleBuf]):(gfxTopRightFramebuffers[currentBuffer^doubleBuf]);
 	}else{
 		if(height)*height=320;
-		return gfxBottomFramebuffers[currentBuffer^1];
+		return gfxBottomFramebuffers[currentBuffer^doubleBuf];
 	}
 }
 
@@ -175,7 +180,7 @@ void gfxFlushBuffers()
 
 void gfxSwapBuffers()
 {
-	currentBuffer^=1;
+	currentBuffer^=doubleBuf;
 	gfxSetFramebufferInfo(GFX_TOP, currentBuffer);
 	gfxSetFramebufferInfo(GFX_BOTTOM, currentBuffer);
 	GSPGPU_SetBufferSwap(NULL, GFX_TOP, &topFramebufferInfo);
@@ -184,7 +189,7 @@ void gfxSwapBuffers()
 
 void gfxSwapBuffersGpu()
 {
-	currentBuffer^=1;
+	currentBuffer^=doubleBuf;
 	gfxSetFramebufferInfo(GFX_TOP, currentBuffer);
 	gfxSetFramebufferInfo(GFX_BOTTOM, currentBuffer);
 	gfxWriteFramebufferInfo(GFX_TOP);