Merge pull request #4656 from hthh/cmpr-fixes

TextureDecoder: Fix off-by-one errors in CMPR

1 files changed, 5 insertions, 23 deletions

diff --git a/Source/Core/VideoCommon/TextureDecoder_Common.cpp b/Source/Core/VideoCommon/TextureDecoder_Common.cpp
index cdaba05bc2..7f151b2406 100644
--- a/Source/Core/VideoCommon/TextureDecoder_Common.cpp
+++ b/Source/Core/VideoCommon/TextureDecoder_Common.cpp
@@ -10,6 +10,7 @@
 #include "Common/MsgHandler.h"
 #include "VideoCommon/LookUpTables.h"
 #include "VideoCommon/TextureDecoder.h"
+#include "VideoCommon/TextureDecoder_Util.h"
 #include "VideoCommon/sfont.inc"
 
 static bool TexFmt_Overlay_Enable = false;
@@ -422,18 +423,6 @@ static inline u32 DecodePixel_Paletted(u16 pixel, TlutFormat tlutfmt)
   }
 }
 
-struct DXTBlock
-{
-  u16 color1;
-  u16 color2;
-  u8 lines[4];
-};
-
-static inline u32 MakeRGBA(int r, int g, int b, int a)
-{
-  return (a << 24) | (b << 16) | (g << 8) | r;
-}
-
 void TexDecoder_DecodeTexel(u8* dst, const u8* src, int s, int t, int imageWidth, int texformat,
                             const u8* tlut_, TlutFormat tlutfmt)
 {
@@ -654,11 +643,6 @@ void TexDecoder_DecodeTexel(u8* dst, const u8* src, int s, int t, int imageWidth
     int red1 = Convert5To8((c1 >> 11) & 0x1F);
     int red2 = Convert5To8((c2 >> 11) & 0x1F);
 
-    // Approximation of x/3: 3/8 (1/2 - 1/8)
-    int blue3 = ((blue2 - blue1) >> 1) - ((blue2 - blue1) >> 3);
-    int green3 = ((green2 - green1) >> 1) - ((green2 - green1) >> 3);
-    int red3 = ((red2 - red1) >> 1) - ((red2 - red1) >> 3);
-
     u16 ss = s & 3;
     u16 tt = t & 3;
 
@@ -680,20 +664,18 @@ void TexDecoder_DecodeTexel(u8* dst, const u8* src, int s, int t, int imageWidth
       color = MakeRGBA(red2, green2, blue2, 255);
       break;
     case 2:
-      color = MakeRGBA(red1 + red3, green1 + green3, blue1 + blue3, 255);
+      color = MakeRGBA(DXTBlend(red2, red1), DXTBlend(green2, green1), DXTBlend(blue2, blue1), 255);
       break;
     case 3:
-      color = MakeRGBA(red2 - red3, green2 - green3, blue2 - blue3, 255);
+      color = MakeRGBA(DXTBlend(red1, red2), DXTBlend(green1, green2), DXTBlend(blue1, blue2), 255);
       break;
     case 6:
-      color =
-          MakeRGBA((red1 + red2 + 1) / 2, (green1 + green2 + 1) / 2, (blue1 + blue2 + 1) / 2, 255);
+      color = MakeRGBA((red1 + red2) / 2, (green1 + green2) / 2, (blue1 + blue2) / 2, 255);
       break;
     case 7:
       // color[3] is the same as color[2] (average of both colors), but transparent.
       // This differs from DXT1 where color[3] is transparent black.
-      color =
-          MakeRGBA((red1 + red2 + 1) / 2, (green1 + green2 + 1) / 2, (blue1 + blue2 + 1) / 2, 0);
+      color = MakeRGBA((red1 + red2) / 2, (green1 + green2) / 2, (blue1 + blue2) / 2, 0);
       break;
     default:
       color = 0;