From 3f7ea1fda990ce1d9809db7d32c23a6dda1a2820 Mon Sep 17 00:00:00 2001
From: Flyinghead <raphael.jean@gmail.com>
Date: Fri, 7 Feb 2020 20:41:59 +0100
Subject: [PATCH] fix crash for 1x1 TW textures

---
 core/rend/TexCache.cpp |  6 +++---
 core/rend/TexCache.h   | 42 ++++++++++++++++++------------------------
 2 files changed, 21 insertions(+), 27 deletions(-)

diff --git a/core/rend/TexCache.cpp b/core/rend/TexCache.cpp
index f2ec61df2..d611e6092 100644
--- a/core/rend/TexCache.cpp
+++ b/core/rend/TexCache.cpp
@@ -23,7 +23,7 @@ u32 palette32_ram[1024];
 u32 pal_hash_256[4];
 u32 pal_hash_16[64];
 
-u32 detwiddle[2][10][1024];
+u32 detwiddle[2][11][1024];
 //input : address in the yyyyyxxxxx format
 //output : address in the xyxyxyxy format
 //U : x resolution , V : y resolution
@@ -64,10 +64,10 @@ static u32 twiddle_slow(u32 x,u32 y,u32 x_sz,u32 y_sz)
 
 static void BuildTwiddleTables()
 {
-	for (u32 s = 0; s < 10; s++)
+	for (u32 s = 0; s < 11; s++)
 	{
 		u32 x_sz = 1024;
-		u32 y_sz = 2 << s;
+		u32 y_sz = 1 << s;
 		for (u32 i = 0; i < x_sz; i++)
 		{
 			detwiddle[0][s][i] = twiddle_slow(i, 0, x_sz, y_sz);
diff --git a/core/rend/TexCache.h b/core/rend/TexCache.h
index 0a0b8f728..b74091b63 100644
--- a/core/rend/TexCache.h
+++ b/core/rend/TexCache.h
@@ -17,7 +17,7 @@ extern u32 pal_hash_256[4];
 extern u32 pal_hash_16[64];
 extern bool KillTex;
 
-extern u32 detwiddle[2][10][1024];
+extern u32 detwiddle[2][11][1024];
 
 template<class pixel_type>
 class PixelBuffer
@@ -522,22 +522,19 @@ void texture_PL(PixelBuffer<pixel_type>* pb,u8* p_in,u32 Width,u32 Height)
 template<class PixelConvertor, class pixel_type>
 void texture_TW(PixelBuffer<pixel_type>* pb,u8* p_in,u32 Width,u32 Height)
 {
-	pb->amove(0,0);
+	pb->amove(0, 0);
 
-	const u32 divider=PixelConvertor::xpp*PixelConvertor::ypp;
+	const u32 divider = PixelConvertor::xpp * PixelConvertor::ypp;
 
-	unsigned long bcx_,bcy_;
-	bcx_=bitscanrev(Width);
-	bcy_=bitscanrev(Height);
-	const u32 bcx=bcx_-1;
-	const u32 bcy=bcy_-1;
+	const u32 bcx = bitscanrev(Width);
+	const u32 bcy = bitscanrev(Height);
 
-	for (u32 y=0;y<Height;y+=PixelConvertor::ypp)
+	for (u32 y = 0; y < Height; y += PixelConvertor::ypp)
 	{
-		for (u32 x=0;x<Width;x+=PixelConvertor::xpp)
+		for (u32 x = 0; x < Width; x += PixelConvertor::xpp)
 		{
-			u8* p = &p_in[(twop(x,y,bcx,bcy)/divider)<<3];
-			PixelConvertor::Convert(pb,p);
+			u8* p = &p_in[(twop(x, y, bcx, bcy) / divider) << 3];
+			PixelConvertor::Convert(pb, p);
 
 			pb->rmovex(PixelConvertor::xpp);
 		}
@@ -548,22 +545,19 @@ void texture_TW(PixelBuffer<pixel_type>* pb,u8* p_in,u32 Width,u32 Height)
 template<class PixelConvertor, class pixel_type>
 void texture_VQ(PixelBuffer<pixel_type>* pb,u8* p_in,u32 Width,u32 Height)
 {
-	p_in+=256*4*2;
-	pb->amove(0,0);
+	p_in += 256 * 4 * 2;	// Skip VQ codebook
+	pb->amove(0, 0);
 
-	const u32 divider=PixelConvertor::xpp*PixelConvertor::ypp;
-	unsigned long bcx_,bcy_;
-	bcx_=bitscanrev(Width);
-	bcy_=bitscanrev(Height);
-	const u32 bcx=bcx_-1;
-	const u32 bcy=bcy_-1;
+	const u32 divider = PixelConvertor::xpp * PixelConvertor::ypp;
+	const u32 bcx = bitscanrev(Width);
+	const u32 bcy = bitscanrev(Height);
 
-	for (u32 y=0;y<Height;y+=PixelConvertor::ypp)
+	for (u32 y = 0; y < Height; y += PixelConvertor::ypp)
 	{
-		for (u32 x=0;x<Width;x+=PixelConvertor::xpp)
+		for (u32 x = 0; x < Width; x += PixelConvertor::xpp)
 		{
-			u8 p = p_in[twop(x,y,bcx,bcy)/divider];
-			PixelConvertor::Convert(pb,&vq_codebook[p*8]);
+			u8 p = p_in[twop(x, y, bcx, bcy) / divider];
+			PixelConvertor::Convert(pb, &vq_codebook[p * 8]);
 
 			pb->rmovex(PixelConvertor::xpp);
 		}