From 85dfaaa2c2f8894204b9a6fb4e867dd54dfde219 Mon Sep 17 00:00:00 2001
From: Alibek Omarov <a1ba.omarov@gmail.com>
Date: Fri, 19 Jul 2024 06:34:48 +0300
Subject: [PATCH] engine: imagelib: add LUMP_TEXGAMMA palette kind to only pass
 HL textures through texgamma, not Quake

---
 engine/common/imagelib/imagelib.h  | 13 +++++++------
 engine/common/imagelib/img_utils.c | 15 ++++++++++++---
 engine/common/imagelib/img_wad.c   | 12 +++++++++++-
 3 files changed, 30 insertions(+), 10 deletions(-)

diff --git a/engine/common/imagelib/imagelib.h b/engine/common/imagelib/imagelib.h
index 0182719d..71894961 100644
--- a/engine/common/imagelib/imagelib.h
+++ b/engine/common/imagelib/imagelib.h
@@ -108,12 +108,13 @@ typedef struct imglib_s
 
 enum
 {
-	LUMP_NORMAL = 0,		// no alpha
-	LUMP_MASKED,		// 1-bit alpha channel masked texture
-	LUMP_GRADIENT,		// gradient image (decals)
-	LUMP_EXTENDED,		// bmp images have extened palette with alpha-channel
-	LUMP_HALFLIFE,		// get predefined half-life palette
-	LUMP_QUAKE1		// get predefined quake palette
+	LUMP_NORMAL = 0, // no alpha
+	LUMP_MASKED,     // 1-bit alpha channel masked texture
+	LUMP_GRADIENT,   // gradient image (decals)
+	LUMP_EXTENDED,   // bmp images have extened palette with alpha-channel
+	LUMP_HALFLIFE,   // get predefined half-life palette
+	LUMP_QUAKE1,     // get predefined quake palette
+	LUMP_TEXGAMMA,   // apply texgamma on top of palette, for half-life mips
 };
 
 enum
diff --git a/engine/common/imagelib/img_utils.c b/engine/common/imagelib/img_utils.c
index f064cc79..d01f1e86 100644
--- a/engine/common/imagelib/img_utils.c
+++ b/engine/common/imagelib/img_utils.c
@@ -293,9 +293,18 @@ static void Image_SetPalette( const byte *pal, uint *d_table )
 	case LUMP_NORMAL:
 		for( i = 0; i < 256; i++ )
 		{
-			rgba[0] = TextureToGamma( pal[i*3+0] );
-			rgba[1] = TextureToGamma( pal[i*3+1] );
-			rgba[2] = TextureToGamma( pal[i*3+2] );
+			memcpy( rgba, &pal[i * 3], 3 );
+			rgba[3] = 0xFF;
+			memcpy( &uirgba, rgba, sizeof( uirgba ));
+			d_table[i] = uirgba;
+		}
+		break;
+	case LUMP_TEXGAMMA:
+		for( i = 0; i < 256; i++ )
+		{
+			rgba[0] = TextureToGamma( pal[i * 3 + 0] );
+			rgba[1] = TextureToGamma( pal[i * 3 + 1] );
+			rgba[2] = TextureToGamma( pal[i * 3 + 2] );
 			rgba[3] = 0xFF;
 			memcpy( &uirgba, rgba, sizeof( uirgba ));
 			d_table[i] = uirgba;
diff --git a/engine/common/imagelib/img_wad.c b/engine/common/imagelib/img_wad.c
index 42269187..094efaf7 100644
--- a/engine/common/imagelib/img_wad.c
+++ b/engine/common/imagelib/img_wad.c
@@ -427,8 +427,18 @@ qboolean Image_LoadMIP( const char *name, const byte *buffer, fs_offset_t filesi
 			}
 
 			if( pal_type == PAL_QUAKE1 )
+			{
 				SetBits( image.flags, IMAGE_QUAKEPAL );
-			rendermode = LUMP_NORMAL;
+
+				// if texture was converted from quake to half-life with no palette changes
+				// then applying texgamma might make it too dark or even outright broken
+				rendermode = LUMP_NORMAL;
+			}
+			else
+			{
+				// half-life mips need texgamma applied
+				rendermode = LUMP_TEXGAMMA;
+			}
 		}
 
 		Image_GetPaletteLMP( pal, rendermode );