renderer: implement mapOverBrightBits in GLSL

src/engine/renderer/gl_shader.cpp

@@ -1573,6 +1573,7 @@ void GLShader_generic2D::SetShaderProgramUniforms( shaderProgram_t *shaderProgra
 
 GLShader_generic::GLShader_generic( GLShaderManager *manager ) :
 	GLShader( "generic", ATTR_POSITION | ATTR_TEXCOORD | ATTR_QTANGENT, manager ),
+	u_MapOverBrightBitsShift( this ),
 	u_TextureMatrix( this ),
 	u_ViewOrigin( this ),
 	u_ViewUp( this ),
@@ -1610,6 +1611,7 @@ void GLShader_generic::SetShaderProgramUniforms( shaderProgram_t *shaderProgram
 GLShader_lightMapping::GLShader_lightMapping( GLShaderManager *manager ) :
 	GLShader( "lightMapping",
 	ATTR_POSITION | ATTR_TEXCOORD | ATTR_QTANGENT | ATTR_COLOR, manager ),
+	u_MapOverBrightBitsShift( this ),
 	u_TextureMatrix( this ),
 	u_SpecularExponent( this ),
 	u_ColorModulate( this ),

src/engine/renderer/gl_shader.h

@@ -1304,6 +1304,21 @@ class GLCompileMacro_USE_ALPHA_TESTING :
 	}
 };
 
+class u_MapOverBrightBitsShift :
+	GLUniform1i
+{
+public:
+	u_MapOverBrightBitsShift( GLShader *shader ) :
+		GLUniform1i( shader, "u_MapOverBrightBitsShift" )
+	{
+	}
+
+	void SetUniform_MapOverBrightBitsShift( int mapOverBrightBitsShift )
+	{
+		this->SetValue( mapOverBrightBitsShift );
+	}
+};
+
 class u_TextureMatrix :
 	GLUniformMatrix4f
 {
@@ -2238,6 +2253,7 @@ class GLShader_generic2D :
 
 class GLShader_generic :
 	public GLShader,
+	public u_MapOverBrightBitsShift,
 	public u_TextureMatrix,
 	public u_ViewOrigin,
 	public u_ViewUp,
@@ -2267,6 +2283,7 @@ class GLShader_generic :
 
 class GLShader_lightMapping :
 	public GLShader,
+	public u_MapOverBrightBitsShift,
 	public u_TextureMatrix,
 	public u_SpecularExponent,
 	public u_ColorModulate,

src/engine/renderer/glsl_source/generic_fp.glsl

@@ -33,8 +33,26 @@ IN(smooth) vec2         var_FadeDepth;
 uniform sampler2D       u_DepthMap;
 #endif
 
+#if !defined(GENERIC_2D) && defined(USE_TCGEN_LIGHTMAP)
+uniform int u_MapOverBrightBitsShift;
+#endif
+
 DECLARE_OUTPUT(vec4)
 
+void mapOverBrightBits(inout vec3 color, in float shift)
+{
+	if (shift > 1)
+	{
+		color *= shift;
+		float maxComponent = 1.0;
+		maxComponent = max(maxComponent, color.r);
+		maxComponent = max(maxComponent, color.g);
+		maxComponent = max(maxComponent, color.b);
+		maxComponent = 1.0 / maxComponent;
+		color *= maxComponent;
+	}
+}
+
 void	main()
 {
 	vec4 color = texture2D(u_ColorMap, var_TexCoords);
@@ -53,7 +71,12 @@ void	main()
 	color.a *= smoothstep(gl_FragCoord.z, fadeDepth, depth);
 #endif
 
+#if !defined(GENERIC_2D) && defined(USE_TCGEN_LIGHTMAP)
+	mapOverBrightBits(color.rgb, u_MapOverBrightBitsShift);
+#endif
+
 	color *= var_Color;
+
 	outputColor = color;
 
 #if defined(GENERIC_2D)

src/engine/renderer/glsl_source/lightMapping_fp.glsl

@@ -59,8 +59,24 @@ IN(smooth) vec3		var_Normal;
 	uniform vec3 u_LightGridScale;
 #endif
 
+uniform int u_MapOverBrightBitsShift;
+
 DECLARE_OUTPUT(vec4)
 
+void mapOverBrightBits(inout vec3 color, in float shift)
+{
+	if (shift > 1)
+	{
+		color *= shift;
+		float maxComponent = 1.0;
+		maxComponent = max(maxComponent, color.r);
+		maxComponent = max(maxComponent, color.g);
+		maxComponent = max(maxComponent, color.b);
+		maxComponent = 1.0 / maxComponent;
+		color *= maxComponent;
+	}
+}
+
 void main()
 {
 	// Compute view direction in world space.
@@ -124,6 +140,8 @@ void main()
 		vec3 ambientColor, lightColor;
 		ReadLightGrid(texture3D(u_LightGrid1, lightGridPos), ambientColor, lightColor);
 
+		mapOverBrightBits(ambientColor.rgb, u_MapOverBrightBitsShift);
+
 		color.rgb = ambientColor * r_AmbientScale * diffuse.rgb;
 	#endif
 
@@ -153,6 +171,8 @@ void main()
 		lightColor /= clamp(dot(normalize(var_Normal), lightDir), 0.3, 1.0);
 	#endif
 
+	mapOverBrightBits(lightColor.rgb, u_MapOverBrightBitsShift);
+
 	// Blend static light.
 	#if defined(USE_DELUXE_MAPPING) || defined(USE_GRID_DELUXE_MAPPING)
 		computeDeluxeLight(lightDir, normal, viewDir, lightColor, diffuse, material, color);

src/engine/renderer/tr_bsp.cpp

@@ -46,118 +46,6 @@ static int        c_vboShadowSurfaces;
 
 //===============================================================================
 
-/*
-===============
-R_ColorShiftLightingBytes
-===============
-*/
-static void R_ColorShiftLightingBytes( byte in[ 4 ], byte out[ 4 ] )
-{
-	int shift, r, g, b;
-
-	/* Shift the color data based on overbright range.
-
-	Historically the shift was:
-
-	  shift = tr.mapOverBrightBits - tr.overbrightBits;
-
-	But in Dæmon engine tr.overbrightBits is always zero
-	as this value is zero when there hardware overbright
-	bit is disabled, and the engine doesn't implement
-	hardware overbright bit at all.
-
-	The original code was there to only shift in software
-	what hardware overbright bit feature was not doing, but
-	this implementation is entirely software. */
-	shift = tr.mapOverBrightBits;
-
-	// shift the data based on overbright range
-	r = in[ 0 ] << shift;
-	g = in[ 1 ] << shift;
-	b = in[ 2 ] << shift;
-
-	// normalize by color instead of saturating to white
-	if ( ( r | g | b ) > 255 )
-	{
-		int max;
-
-		max = r > g ? r : g;
-		max = max > b ? max : b;
-		r = r * 255 / max;
-		g = g * 255 / max;
-		b = b * 255 / max;
-	}
-
-	out[ 0 ] = r;
-	out[ 1 ] = g;
-	out[ 2 ] = b;
-	out[ 3 ] = in[ 3 ];
-}
-
-static void R_ColorShiftLightingBytesCompressed( byte in[ 8 ], byte out[ 8 ] )
-{
-	unsigned short rgb565;
-	byte rgba[4];
-
-	// color shift the endpoint colors in the dxt block
-	rgb565 = in[1] << 8 | in[0];
-	rgba[0] = (rgb565 >> 8) & 0xf8;
-	rgba[1] = (rgb565 >> 3) & 0xfc;
-	rgba[2] = (rgb565 << 3) & 0xf8;
-	rgba[3] = 0xff;
-	R_ColorShiftLightingBytes( rgba, rgba );
-	rgb565 = ((rgba[0] >> 3) << 11) |
-		((rgba[1] >> 2) << 5) |
-		((rgba[2] >> 3) << 0);
-	out[0] = rgb565 & 0xff;
-	out[1] = rgb565 >> 8;
-
-	rgb565 = in[3] << 8 | in[2];
-	rgba[0] = (rgb565 >> 8) & 0xf8;
-	rgba[1] = (rgb565 >> 3) & 0xfc;
-	rgba[2] = (rgb565 << 3) & 0xf8;
-	rgba[3] = 0xff;
-	R_ColorShiftLightingBytes( rgba, rgba );
-	rgb565 = ((rgba[0] >> 3) << 11) |
-		((rgba[1] >> 2) << 5) |
-		((rgba[2] >> 3) << 0);
-	out[2] = rgb565 & 0xff;
-	out[3] = rgb565 >> 8;
-}
-
-/*
-===============
-R_ProcessLightmap
-
-        returns maxIntensity
-===============
-*/
-float R_ProcessLightmap( byte *pic, int in_padding, int width, int height, int bits, byte *pic_out )
-{
-	int   j;
-	float maxIntensity = 0;
-
-	if( bits & IF_BC1 ) {
-		for ( j = 0; j < ((width + 3) >> 2) * ((height + 3) >> 2); j++ )
-		{
-			R_ColorShiftLightingBytesCompressed( &pic[ j * 8 ], &pic_out[ j * 8 ] );
-		}
-	} else if( bits & (IF_BC2 | IF_BC3) ) {
-		for ( j = 0; j < ((width + 3) >> 2) * ((height + 3) >> 2); j++ )
-		{
-			R_ColorShiftLightingBytesCompressed( &pic[ j * 16 ], &pic_out[ j * 16 ] );
-		}
-	} else {
-		for ( j = 0; j < width * height; j++ )
-		{
-			R_ColorShiftLightingBytes( &pic[ j * in_padding ], &pic_out[ j * 4 ] );
-			pic_out[ j * 4 + 3 ] = 255;
-		}
-	}
-
-	return maxIntensity;
-}
-
 static int LightmapNameCompare( const char *s1, const char *s2 )
 {
 	int  c1, c2;
@@ -640,7 +528,7 @@ static void R_LoadLightmaps( lump_t *l, const char *bspName )
 					lightMapBuffer[( index * 4 ) + 2 ] = buf_p[( ( x + ( y * internalLightMapSize ) ) * 3 ) + 2 ];
 					lightMapBuffer[( index * 4 ) + 3 ] = 255;
 
-					R_ColorShiftLightingBytes( &lightMapBuffer[( index * 4 ) + 0 ], &lightMapBuffer[( index * 4 ) + 0 ] );
+					// Color shift for overbright bits is now done in GLSL.
 				}
 			}
 
@@ -925,7 +813,7 @@ static void ParseFace( dsurface_t *ds, drawVert_t *verts, bspSurface_t *surf, in
 		cv->verts[ i ].lightColor = Color::Adapt( verts[ i ].color );
 
 
-		R_ColorShiftLightingBytes( cv->verts[ i ].lightColor.ToArray(), cv->verts[ i ].lightColor.ToArray() );
+		// Color shift for overbright bits is now done in GLSL.
 	}
 
 	// copy triangles
@@ -1132,7 +1020,7 @@ static void ParseMesh( dsurface_t *ds, drawVert_t *verts, bspSurface_t *surf )
 
 		points[ i ].lightColor = Color::Adapt( verts[ i ].color );
 
-		R_ColorShiftLightingBytes( points[ i ].lightColor.ToArray(), points[ i ].lightColor.ToArray() );
+		// Color shift for overbright bits is now done in GLSL.
 	}
 
 	// center texture coords
@@ -1256,7 +1144,7 @@ static void ParseTriSurf( dsurface_t *ds, drawVert_t *verts, bspSurface_t *surf,
 
 			cv->verts[ i ].lightColor = Color::Adapt( verts[ i ].color );
 
-		R_ColorShiftLightingBytes( cv->verts[ i ].lightColor.ToArray(), cv->verts[ i ].lightColor.ToArray() );
+		// Color shift for overbright bits is now done in GLSL.
 	}
 
 	// copy triangles
@@ -4044,8 +3932,7 @@ void R_LoadLightGrid( lump_t *l )
 		tmpDirected[ 2 ] = in->directed[ 2 ];
 		tmpDirected[ 3 ] = 255;
 
-		R_ColorShiftLightingBytes( tmpAmbient, tmpAmbient );
-		R_ColorShiftLightingBytes( tmpDirected, tmpDirected );
+		// Color shift for overbright bits is now done in GLSL.
 
 		for ( j = 0; j < 3; j++ )
 		{
@@ -6922,4 +6809,6 @@ void RE_LoadWorldMap( const char *name )
 			}
 		}
 	}
+
+	tr.mapOverBrightBitsShift = pow(2, tr.mapOverBrightBits);
 }

src/engine/renderer/tr_image.cpp

@@ -1798,10 +1798,7 @@ image_t *R_FindImageFile( const char *imageName, imageParams_t &imageParams )
 		return nullptr;
 	}
 
-	if ( imageParams.bits & IF_LIGHTMAP )
-	{
-		R_ProcessLightmap( pic[ 0 ], 4, width, height, imageParams.bits, pic[ 0 ] );
-	}
+	// Color shift for overbright bits is now done in GLSL.
 
 	image = R_CreateImage( ( char * ) buffer, (const byte **)pic, width, height, numMips, imageParams );
 

src/engine/renderer/tr_local.h

@@ -2822,7 +2822,8 @@ enum class deluxeMode_t { NONE, GRID, MAP };
 
 		viewParms_t    viewParms;
 
-		int            mapOverBrightBits; // r_mapOverbrightBits->integer, but can be overridden by mapper using the worldspawn
+		int mapOverBrightBits; // r_mapOverbrightBits->integer, but can be overridden by mapper using the worldspawn
+		int mapOverBrightBitsShift; // pow(2, mapOverbrightBits)
 
 		orientationr_t orientation; // for current entity
 
@@ -3305,7 +3306,6 @@ inline bool checkGLErrors()
 	void      RE_Shutdown( bool destroyWindow );
 
 	bool   R_GetEntityToken( char *buffer, int size );
-	float      R_ProcessLightmap( byte *pic, int in_padding, int width, int height, int bits, byte *pic_out );  // Arnout
 
 	model_t    *R_AllocModel();
 

src/engine/renderer/tr_shade.cpp

@@ -732,6 +732,12 @@ static void Render_generic( shaderStage_t *pStage )
 		gl_genericShader->SetUniform_AlphaTest(pStage->stateBits);
 	}
 
+	// u_MapOverBrightBitsShift
+	if ( pStage->tcGen_Lightmap )
+	{
+		gl_genericShader->SetUniform_MapOverBrightBitsShift( tr.mapOverBrightBitsShift );
+	}
+
 	// u_ColorGen
 	switch ( pStage->rgbGen )
 	{
@@ -895,6 +901,7 @@ static void Render_lightMapping( shaderStage_t *pStage )
 
 	lightMode_t lightMode = lightMode_t::FULLBRIGHT;
 	deluxeMode_t deluxeMode = deluxeMode_t::NONE;
+	int mapOverBrightBitsShift = 1;
 
 	/* TODO: investigate what this is. It's probably a hack to detect some
 	specific use case. Without knowing which use case this takes care about,
@@ -949,6 +956,7 @@ static void Render_lightMapping( shaderStage_t *pStage )
 	switch ( lightMode )
 	{
 		case lightMode_t::VERTEX:
+			mapOverBrightBitsShift = tr.mapOverBrightBitsShift;
 			// Do not rewrite pStage->rgbGen.
 			colorGen = colorGen_t::CGEN_VERTEX;
 			tess.svars.color.SetRed( 0.0f );
@@ -957,12 +965,14 @@ static void Render_lightMapping( shaderStage_t *pStage )
 			break;
 
 		case lightMode_t::GRID:
+			mapOverBrightBitsShift = tr.mapOverBrightBitsShift;
 			// Store lightGrid1 as lightmap,
 			// the GLSL code will know how to deal with it.
 			lightmap = tr.lightGrid1Image;
 			break;
 
 		case lightMode_t::MAP:
+			mapOverBrightBitsShift = tr.mapOverBrightBitsShift;
 			lightmap = GetLightMap();
 
 			if ( r_showLightMaps->integer )
@@ -1085,6 +1095,9 @@ static void Render_lightMapping( shaderStage_t *pStage )
 	// u_AlphaTest
 	gl_lightMappingShader->SetUniform_AlphaTest( pStage->stateBits );
 
+	// u_MapOverBrightBitsShift
+	gl_lightMappingShader->SetUniform_MapOverBrightBitsShift( mapOverBrightBitsShift );
+
 	// bind u_HeightMap
 	if ( pStage->enableReliefMapping )
 	{