fixup: fix special cases

Author: slipher

src/engine/renderer/Material.cpp

@@ -226,7 +226,8 @@ void UpdateSurfaceDataGeneric3D( uint32_t* materials, Material& material, drawSu
 	colorGen_t rgbGen = SetRgbGen( pStage );
 	alphaGen_t alphaGen = SetAlphaGen( pStage );
 
-	gl_genericShaderMaterial->SetUniform_ColorModulate( rgbGen, alphaGen );
+	bool mayUseVertexOverbright = pStage->type == stageType_t::ST_COLORMAP && drawSurf->bspSurface;
+	gl_genericShaderMaterial->SetUniform_ColorModulate( rgbGen, alphaGen, mayUseVertexOverbright );
 
 	Tess_ComputeColor( pStage );
 	gl_genericShaderMaterial->SetUniform_Color( tess.svars.color );

src/engine/renderer/gl_shader.h

@@ -3602,7 +3602,7 @@ class u_ColorModulate :
 	{
 		this->SetValue( v );
 	}
-	void SetUniform_ColorModulate( colorGen_t colorGen, alphaGen_t alphaGen )
+	void SetUniform_ColorModulate( colorGen_t colorGen, alphaGen_t alphaGen, bool vertexOverbright = false )
 	{
 		vec4_t v;
 		bool needAttrib = false;
@@ -3616,7 +3616,16 @@ class u_ColorModulate :
 		{
 			case colorGen_t::CGEN_VERTEX:
 				needAttrib = true;
-				VectorSet( v, 1, 1, 1 );
+				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
+					VectorSet( v, tr.mapLightFactor, tr.mapLightFactor, tr.mapLightFactor );
+				}
+				else
+				{
+					VectorSet( v, 1, 1, 1 );
+				}
 				break;
 
 			case colorGen_t::CGEN_ONE_MINUS_VERTEX:

src/engine/renderer/tr_shade.cpp

@@ -924,7 +924,11 @@ void Render_generic3D( shaderStage_t *pStage )
 	colorGen_t rgbGen = SetRgbGen( pStage );
 	alphaGen_t alphaGen = SetAlphaGen( pStage );
 
-	gl_genericShader->SetUniform_ColorModulate( rgbGen, alphaGen );
+	// Here, it's safe to multiply the overbright factor for vertex lighting into the color gen`
+	// since the `generic` fragment shader only takes a single input color. `lightMapping` on the
+	// hand needs to know the real diffuse color, hence the separate u_LightFactor.
+	bool mayUseVertexOverbright = pStage->type == stageType_t::ST_COLORMAP && tess.bspSurface;
+	gl_genericShader->SetUniform_ColorModulate( rgbGen, alphaGen, mayUseVertexOverbright );
 
 	// u_Color
 	gl_genericShader->SetUniform_Color( tess.svars.color );
@@ -1121,7 +1125,8 @@ void Render_lightMapping( shaderStage_t *pStage )
 	gl_lightMappingShader->SetUniform_Time( backEnd.refdef.floatTime - backEnd.currentEntity->e.shaderTime );
 
 	// u_LightFactor
-	gl_lightMappingShader->SetUniform_LightFactor( tr.mapLightFactor );
+	gl_lightMappingShader->SetUniform_LightFactor(
+		lightMode == lightMode_t::FULLBRIGHT ? 1.0f : tr.mapLightFactor );
 
 	// u_ColorModulate
 	gl_lightMappingShader->SetUniform_ColorModulate( rgbGen, alphaGen );
@@ -2565,6 +2570,11 @@ void Tess_ComputeColor( shaderStage_t *pStage )
 			}
 	}
 
+	if ( pStage->type == stageType_t::ST_STYLELIGHTMAP || pStage->type == stageType_t::ST_STYLECOLORMAP )
+	{
+		tess.svars.color *= tr.mapLightFactor;
+	}
+
 	// alphaGen
 	switch ( pStage->alphaGen )
 	{