OpenGL2: Add option in code for alternate overbright method.

code/renderergl2/tr_bsp.c

@@ -101,7 +101,11 @@ static	void R_ColorShiftLightingBytes( byte in[4], byte out[4] ) {
 	int		shift, r, g, b;
 
 	// shift the color data based on overbright range
+#if defined(USE_OVERBRIGHT)
 	shift = r_mapOverBrightBits->integer - tr.overbrightBits;
+#else
+	shift = 0;
+#endif
 
 	// shift the data based on overbright range
 	r = in[0] << shift;
@@ -136,7 +140,9 @@ static void R_ColorShiftLightingFloats(float in[4], float out[4], float scale )
 {
 	float	r, g, b;
 
+#if defined(USE_OVERBRIGHT)
 	scale *= pow(2.0f, r_mapOverBrightBits->integer - tr.overbrightBits);
+#endif
 
 	r = in[0] * scale;
 	g = in[1] * scale;
@@ -2755,7 +2761,11 @@ void R_LoadLightGrid( lump_t *l ) {
 
 		if (hdrLightGrid)
 		{
+#if defined(USE_OVERBRIGHT)
 			float lightScale = pow(2, r_mapOverBrightBits->integer - tr.overbrightBits);
+#else
+			float lightScale = 1.0f;
+#endif
 
 			//ri.Printf(PRINT_ALL, "found!\n");
 

code/renderergl2/tr_image.c

@@ -2855,7 +2855,11 @@ void R_SetColorMappings( void ) {
 	int		inf;
 
 	// setup the overbright lighting
+#if defined(USE_OVERBRIGHT)
 	tr.overbrightBits = r_overBrightBits->integer;
+#else
+	tr.overbrightBits = 0;
+#endif
 
 	// allow 2 overbright bits
 	if ( tr.overbrightBits > 2 ) {

code/renderergl2/tr_local.h

@@ -58,6 +58,7 @@ typedef unsigned int glIndex_t;
 #define CUBE_MAP_SIZE      (1 << CUBE_MAP_MIPS)
 
 #define USE_VERT_TANGENT_SPACE
+#define USE_OVERBRIGHT
 
 typedef struct dlight_s {
 	vec3_t	origin;

code/renderergl2/tr_scene.c

@@ -349,7 +349,11 @@ void RE_BeginScene(const refdef_t *fd)
 		}
 		else
 		{
+#if defined(USE_OVERBRIGHT)
 			float scale = pow(2, r_mapOverBrightBits->integer - tr.overbrightBits - 8);
+#else
+			float scale = (1 << r_mapOverBrightBits->integer) / 255.0f;
+#endif
 			if (r_forceSun->integer)
 			{
 				VectorScale(tr.sunLight, scale * r_forceSunLightScale->value,   tr.refdef.sunCol);

code/renderergl2/tr_shade.c

@@ -444,9 +444,22 @@ static void ProjectDlightTexture( void ) {
 
 static void ComputeShaderColors( shaderStage_t *pStage, vec4_t baseColor, vec4_t vertColor, int blend )
 {
+	qboolean isBlend = ((blend & GLS_SRCBLEND_BITS) == GLS_SRCBLEND_DST_COLOR)
+		|| ((blend & GLS_SRCBLEND_BITS) == GLS_SRCBLEND_ONE_MINUS_DST_COLOR)
+		|| ((blend & GLS_DSTBLEND_BITS) == GLS_DSTBLEND_SRC_COLOR)
+		|| ((blend & GLS_DSTBLEND_BITS) == GLS_DSTBLEND_ONE_MINUS_SRC_COLOR);
+
+	qboolean isWorldDraw = !(backEnd.refdef.rdflags & RDF_NOWORLDMODEL);
+
+#if defined(USE_OVERBRIGHT)
+	float exactLight = 1.0f;
+#else
+	float exactLight = (isBlend || !isWorldDraw) ? 1.0f : (float)(1 << r_mapOverBrightBits->integer);
+#endif
+
 	baseColor[0] = 
 	baseColor[1] =
-	baseColor[2] =
+	baseColor[2] = exactLight;
 	baseColor[3] = 1.0f;
 
 	vertColor[0] =
@@ -473,7 +486,7 @@ static void ComputeShaderColors( shaderStage_t *pStage, vec4_t baseColor, vec4_t
 
 			vertColor[0] =
 			vertColor[1] =
-			vertColor[2] = 
+			vertColor[2] = exactLight;
 			vertColor[3] = 1.0f;
 			break;
 		case CGEN_CONST:
@@ -601,11 +614,7 @@ static void ComputeShaderColors( shaderStage_t *pStage, vec4_t baseColor, vec4_t
 	}
 
 	// multiply color by overbrightbits if this isn't a blend
-	if (tr.overbrightBits 
+	if (tr.overbrightBits && !isBlend)
-	 && !((blend & GLS_SRCBLEND_BITS) == GLS_SRCBLEND_DST_COLOR)
-	 && !((blend & GLS_SRCBLEND_BITS) == GLS_SRCBLEND_ONE_MINUS_DST_COLOR)
-	 && !((blend & GLS_DSTBLEND_BITS) == GLS_DSTBLEND_SRC_COLOR)
-	 && !((blend & GLS_DSTBLEND_BITS) == GLS_DSTBLEND_ONE_MINUS_SRC_COLOR))
 	{
 		float scale = 1 << tr.overbrightBits;