From d66fd4ab85af926d05b75fec5ec0f2c66f1d5e31 Mon Sep 17 00:00:00 2001
From: luigi__ <luigi__@users.sf.net>
Date: Sun, 1 Feb 2009 00:24:03 +0000
Subject: [PATCH] Rewritten the incorrectly implemented
 setFinalBGColorSpecialIncreaseWnd and setFinalBGColorSpecialDecreaseWnd
 functions. This fixes the part 1 of the glitch #2488334 (SPP puzzle glitch).

---
 desmume/src/GPU.cpp | 68 +++++++++++++++++++++++----------------------
 1 file changed, 35 insertions(+), 33 deletions(-)

diff --git a/desmume/src/GPU.cpp b/desmume/src/GPU.cpp
index dfb796741..b3a429744 100644
--- a/desmume/src/GPU.cpp
+++ b/desmume/src/GPU.cpp
@@ -431,9 +431,9 @@ u16 GPU::blend(u16 colA, u16 colB)
 
 void GPU_setMasterBrightness (GPU *gpu, u16 val)
 {
-	if(!nds.isInVblank()) {
+	if(!nds.isInVblank()) {
 		PROGINFO("Changing master brightness outside of vblank\n");
-	}
+	}
  	gpu->MasterBrightFactor = (val & 0x1F);
 	gpu->MasterBrightMode	= (val>>14);
 }
@@ -777,20 +777,21 @@ static void setFinalBGColorSpecialIncreaseWnd (GPU *gpu, u8 *dst, u16 color, u8
 	
 	gpu->renderline_checkWindows(x, windowDraw, windowEffect);
 
-	if (((gpu->BLDCNT >> gpu->currBgNum)&1) && windowEffect)   // the bg to draw has a special color effect
+	if(windowDraw)
 	{
-		if (gpu->BLDY_EVY != 0x0)
-		{ // dont slow down if there is nothing to do
-		}
-
-		T2WriteWord(dst, 0, color) ;
-		gpu->bgPixels[x] = gpu->currBgNum;
-	}
-	else
-	{
-		if ((windowEffect && (gpu->BLDCNT & (0x100 << gpu->currBgNum))) || windowDraw)
+		if((gpu->BLDCNT & (1 << gpu->currBgNum)) && windowEffect)
 		{
-			T2WriteWord(dst, 0, color);
+			if (gpu->BLDY_EVY != 0x0)
+			{
+				color = fadeInColors[gpu->BLDY_EVY][color&0x7FFF];
+			}
+
+			T2WriteWord(dst, 0, (color | 0x8000));
+			gpu->bgPixels[x] = gpu->currBgNum;
+		}
+		else
+		{
+			T2WriteWord(dst, 0, (color | 0x8000));
 			gpu->bgPixels[x] = gpu->currBgNum;
 		}
 	}
@@ -802,20 +803,21 @@ static void setFinalBGColorSpecialDecreaseWnd (GPU *gpu, u8 *dst, u16 color, u8
 	
 	gpu->renderline_checkWindows(x, windowDraw, windowEffect);
 
-	if (((gpu->BLDCNT >> gpu->currBgNum)&1) && windowEffect)   // the bg to draw has a special color effect
+	if(windowDraw)
 	{
-		if (gpu->BLDY_EVY != 0x0)
-		{ // dont slow down if there is nothing to do
-			color = (fadeOutColors[gpu->BLDY_EVY][color&0x7FFF] | 0x8000);
-		}
-		T2WriteWord(dst, 0, color) ;
-		gpu->bgPixels[x] = gpu->currBgNum;
-	}
-	else
-	{
-		if ((windowEffect && (gpu->BLDCNT & (0x100 << gpu->currBgNum))) || windowDraw)
+		if((gpu->BLDCNT & (1 << gpu->currBgNum)) && windowEffect)
 		{
-			T2WriteWord(dst, 0, color);
+			if (gpu->BLDY_EVY != 0x0)
+			{
+				color = fadeOutColors[gpu->BLDY_EVY][color&0x7FFF];
+			}
+
+			T2WriteWord(dst, 0, (color | 0x8000));
+			gpu->bgPixels[x] = gpu->currBgNum;
+		}
+		else
+		{
+			T2WriteWord(dst, 0, (color | 0x8000));
 			gpu->bgPixels[x] = gpu->currBgNum;
 		}
 	}
@@ -1423,15 +1425,15 @@ static void setFinal3DColorSpecialDecreaseWnd(GPU *gpu, u32 passing, u8 *dst, u1
 //overhead was ridiculous and terrible
 FORCEINLINE void GPU::__setFinalColorBck(u8 *dst, u16 color, u8 x, bool opaque)
 {
-	//I commented out this line to make a point.
-	//indeed, since x is a u8 we cannot pass in anything >=256
-	//but in fact, someone is going to try. specifically, that is the map viewer debug tools
-	//which try to render the enter BG. in cases where that is large, it could be up to 1024 wide.
-	//I think it survives this truncation to 8bits.
+	//I commented out this line to make a point.
+	//indeed, since x is a u8 we cannot pass in anything >=256
+	//but in fact, someone is going to try. specifically, that is the map viewer debug tools
+	//which try to render the enter BG. in cases where that is large, it could be up to 1024 wide.
+	//I think it survives this truncation to 8bits.
 	//assert(x<256);
 
-	int x_int;
-
+	int x_int;
+
 	//due to this early out, we will get incorrect behavior in cases where 
 	//we enable mosaic in the middle of a frame. this is deemed unlikely.
 	if(!curr_mosaic_enabled) {