Fix colorModulate for lightFactor < 4

Also fixes extra bits beng added to the `lightFactor` part `SetUniform_ColorModulateColorGen` in some cases.

Author: VReaperV

src/engine/renderer/gl_shader.h

@@ -3591,11 +3591,11 @@ class u_ColorModulate :
 };
 
 enum class ColorModulate {
-	COLOR_ADD = BIT( 0 ),
-	COLOR_NEGATE = BIT( 1 ),
+	COLOR_ONE = BIT( 0 ),
+	COLOR_MINUS_ONE = BIT( 1 ),
 	COLOR_LIGHTFACTOR = BIT( 2 ),
-	ALPHA_ADD = BIT( 3 ),
-	ALPHA_NEGATE = BIT( 4 )
+	ALPHA_ONE = BIT( 3 ),
+	ALPHA_MINUS_ONE = BIT( 4 )
 };
 
 class u_ColorModulateColorGen :
@@ -3617,22 +3617,23 @@ class u_ColorModulateColorGen :
 			);
 		}
 
+		uint32_t lightFactor = 0;
 		switch ( colorGen ) {
 			case colorGen_t::CGEN_VERTEX:
 				needAttrib = true;
 				if ( vertexOverbright ) {
 					// vertexOverbright is only needed for non-lightmapped cases. When there is a
 					// lightmap, this is done by multiplying with the overbright-scaled white image
 					colorModulate |= Util::ordinal( ColorModulate::COLOR_LIGHTFACTOR );
-					colorModulate |= uint32_t( tr.mapLightFactor / 4 ) << 5;
+					lightFactor = uint32_t( tr.mapLightFactor ) << 5;
 				} else {
-					colorModulate |= Util::ordinal( ColorModulate::COLOR_ADD );
+					colorModulate |= Util::ordinal( ColorModulate::COLOR_ONE );
 				}
 				break;
 
 			case colorGen_t::CGEN_ONE_MINUS_VERTEX:
 				needAttrib = true;
-				colorModulate |= Util::ordinal( ColorModulate::COLOR_ADD ) | Util::ordinal( ColorModulate::COLOR_NEGATE );
+				colorModulate |= Util::ordinal( ColorModulate::COLOR_MINUS_ONE );
 				break;
 
 			default:
@@ -3641,20 +3642,20 @@ class u_ColorModulateColorGen :
 
 		if ( useMapLightFactor ) {
 			ASSERT_EQ( vertexOverbright, false );
-			colorModulate |= uint32_t( tr.mapLightFactor ) << 5;
-		} else {
-			colorModulate |= 1 << 5;
+			lightFactor = uint32_t( tr.mapLightFactor ) << 5;
 		}
 
+		colorModulate |= lightFactor ? lightFactor : 1 << 5;
+
 		switch ( alphaGen ) {
 			case alphaGen_t::AGEN_VERTEX:
 				needAttrib = true;
-				colorModulate |= Util::ordinal( ColorModulate::ALPHA_ADD );
+				colorModulate |= Util::ordinal( ColorModulate::ALPHA_ONE );
 				break;
 
 			case alphaGen_t::AGEN_ONE_MINUS_VERTEX:
 				needAttrib = true;
-				colorModulate |= Util::ordinal( ColorModulate::ALPHA_ADD ) | Util::ordinal( ColorModulate::ALPHA_NEGATE );
+				colorModulate |= Util::ordinal( ColorModulate::ALPHA_MINUS_ONE );
 				break;
 
 			default:

src/engine/renderer/glsl_source/common.glsl

@@ -43,12 +43,12 @@ array must be in the form of uvec4 array[] */
 #define UINT_FROM_UVEC4_ARRAY( array, id ) ( ( array )[( id ) / 4][( id ) % 4] )
 #define UVEC2_FROM_UVEC4_ARRAY( array, id ) ( ( id ) % 2 == 0 ? ( array )[( id ) / 2].xy : ( array )[( id ) / 2].zw )
 
-/* Bit 0: color add
-Bit 1: color negate
-Bit 2: lightFactor add
-Bit 3: alpha add
-Bit 4: alpha negate
-Bit 5-12: lightFactor */
+/* Bit 0: color * 1
+Bit 1: color * ( -1 )
+Bit 2: color += lightFactor
+Bit 3: alpha * 1
+Bit 4: alpha * ( -1 )
+Bit 5-7: lightFactor */
 
 float colorModArray[3] = float[3] ( 0.0f, 1.0f, -1.0f );
 
@@ -59,11 +59,11 @@ vec4 ColorModulateToColor( const in uint colorMod ) {
 }
 
 vec4 ColorModulateToColor( const in uint colorMod, const in float lightFactor ) {
-	vec4 colorModulate = vec4( colorModArray[colorMod & 3] + ( colorMod & 4 ) * lightFactor );
+	vec4 colorModulate = vec4( colorModArray[colorMod & 3] + ( ( colorMod & 4 ) >> 2 ) * lightFactor );
 	colorModulate.a = ( colorModArray[( colorMod & 24 ) >> 3] );
 	return colorModulate;
 }
 
 float ColorModulateToLightFactor( const in uint colorMod ) {
-	return ( colorMod >> 5 ) & 0xF;
+	return ( colorMod >> 5 ) & 0x7;
 }