From 8779421a3e0f373b0c73d56d28b9a9a4d370d6da Mon Sep 17 00:00:00 2001
From: "Unknown W. Brackets" <checkins@unknownbrackets.org>
Date: Mon, 25 Apr 2022 08:54:02 -0700
Subject: [PATCH] GLES: Reverse alphamask when comparing to CLUT.

The CLUT is already reversed.
---
 GPU/Common/TextureCacheCommon.cpp | 23 ++++++++++++-----------
 GPU/Common/TextureCacheCommon.h   |  2 +-
 2 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/GPU/Common/TextureCacheCommon.cpp b/GPU/Common/TextureCacheCommon.cpp
index 415245bd71..4a651746ed 100644
--- a/GPU/Common/TextureCacheCommon.cpp
+++ b/GPU/Common/TextureCacheCommon.cpp
@@ -1405,12 +1405,12 @@ static CheckAlphaResult DecodeDXTBlocks(uint8_t *out, int outPitch, uint32_t tex
 	}
 }
 
-inline u32 ClutFormatToFullAlpha(GEPaletteFormat fmt) {
+inline u32 ClutFormatToFullAlpha(GEPaletteFormat fmt, bool reverseColors) {
 	switch (fmt) {
-	case GE_CMODE_16BIT_ABGR4444: return 0xF000;
-	case GE_CMODE_16BIT_ABGR5551: return 0x8000;
+	case GE_CMODE_16BIT_ABGR4444: return reverseColors ? 0x000F : 0xF000;
+	case GE_CMODE_16BIT_ABGR5551: return reverseColors ? 0x0001 : 0x8000;
 	case GE_CMODE_32BIT_ABGR8888: return 0xFF000000;
-	case GE_CMODE_16BIT_BGR5650:
+	case GE_CMODE_16BIT_BGR5650: return 0;
 	default: return 0;
 	}
 }
@@ -1420,7 +1420,7 @@ inline u32 TfmtRawToFullAlpha(GETextureFormat fmt) {
 	case GE_TFMT_4444: return 0xF000;
 	case GE_TFMT_5551: return 0x8000;
 	case GE_TFMT_8888: return 0xFF000000;
-	case GE_TFMT_5650:
+	case GE_TFMT_5650: return 0;
 	default: return 0;
 	}
 }
@@ -1489,7 +1489,8 @@ CheckAlphaResult TextureCacheCommon::DecodeTextureLevel(u8 *out, int outPitch, G
 						DeIndexTexture4<u32>((u32 *)(out + outPitch * y), texptr + (bufw * y) / 2, w, expandClut_, &alphaSum);
 					}
 				} else {
-					fullAlphaMask = ClutFormatToFullAlpha(clutformat);
+					// If we're reversing colors, the CLUT was already reversed.
+					fullAlphaMask = ClutFormatToFullAlpha(clutformat, reverseColors);
 					for (int y = 0; y < h; ++y) {
 						DeIndexTexture4<u16>((u16 *)(out + outPitch * y), texptr + (bufw * y) / 2, w, clut, &alphaSum);
 					}
@@ -1521,13 +1522,13 @@ CheckAlphaResult TextureCacheCommon::DecodeTextureLevel(u8 *out, int outPitch, G
 	break;
 
 	case GE_TFMT_CLUT8:
-		return ReadIndexedTex(out, outPitch, level, texptr, 1, bufw, expandTo32bit);
+		return ReadIndexedTex(out, outPitch, level, texptr, 1, bufw, reverseColors, expandTo32bit);
 
 	case GE_TFMT_CLUT16:
-		return ReadIndexedTex(out, outPitch, level, texptr, 2, bufw, expandTo32bit);
+		return ReadIndexedTex(out, outPitch, level, texptr, 2, bufw, reverseColors, expandTo32bit);
 
 	case GE_TFMT_CLUT32:
-		return ReadIndexedTex(out, outPitch, level, texptr, 4, bufw, expandTo32bit);
+		return ReadIndexedTex(out, outPitch, level, texptr, 4, bufw, reverseColors, expandTo32bit);
 
 	case GE_TFMT_4444:
 	case GE_TFMT_5551:
@@ -1643,7 +1644,7 @@ CheckAlphaResult TextureCacheCommon::DecodeTextureLevel(u8 *out, int outPitch, G
 	return AlphaSumIsFull(alphaSum, fullAlphaMask) ? CHECKALPHA_FULL : CHECKALPHA_ANY;
 }
 
-CheckAlphaResult TextureCacheCommon::ReadIndexedTex(u8 *out, int outPitch, int level, const u8 *texptr, int bytesPerIndex, int bufw, bool expandTo32Bit) {
+CheckAlphaResult TextureCacheCommon::ReadIndexedTex(u8 *out, int outPitch, int level, const u8 *texptr, int bytesPerIndex, int bufw, bool reverseColors, bool expandTo32Bit) {
 	int w = gstate.getTextureWidth(level);
 	int h = gstate.getTextureHeight(level);
 
@@ -1665,7 +1666,7 @@ CheckAlphaResult TextureCacheCommon::ReadIndexedTex(u8 *out, int outPitch, int l
 	}
 
 	u32 alphaSum = 0xFFFFFFFF;
-	u32 fullAlphaMask = ClutFormatToFullAlpha(palFormat);
+	u32 fullAlphaMask = ClutFormatToFullAlpha(palFormat, reverseColors);
 
 	switch (palFormat) {
 	case GE_CMODE_16BIT_BGR5650:
diff --git a/GPU/Common/TextureCacheCommon.h b/GPU/Common/TextureCacheCommon.h
index 1c56656e27..7fb47e25ca 100644
--- a/GPU/Common/TextureCacheCommon.h
+++ b/GPU/Common/TextureCacheCommon.h
@@ -284,7 +284,7 @@ protected:
 
 	CheckAlphaResult DecodeTextureLevel(u8 *out, int outPitch, GETextureFormat format, GEPaletteFormat clutformat, uint32_t texaddr, int level, int bufw, bool reverseColors, bool useBGRA, bool expandTo32Bit);
 	void UnswizzleFromMem(u32 *dest, u32 destPitch, const u8 *texptr, u32 bufw, u32 height, u32 bytesPerPixel);
-	CheckAlphaResult ReadIndexedTex(u8 *out, int outPitch, int level, const u8 *texptr, int bytesPerIndex, int bufw, bool expandTo32Bit);
+	CheckAlphaResult ReadIndexedTex(u8 *out, int outPitch, int level, const u8 *texptr, int bytesPerIndex, int bufw, bool reverseColors, bool expandTo32Bit);
 	ReplacedTexture &FindReplacement(TexCacheEntry *entry, int &w, int &h);
 
 	template <typename T>