renderer: add non-bitwise alternative for u_Color and u_ColorModulateColorGen on GLSL 1.20

Add non-bitwise alternative for u_Color and u_ColorModulateColorGen
on GLSL 1.20.

Store the related bitfields as GLUniform1i in all cases, process them
as uint with bitwise operations when supported, or as int with bitwise
emulation otherwise.

Author: illwieckz

src/engine/renderer/gl_shader.h

@@ -3043,17 +3043,22 @@ class u_CloudHeight :
 };
 
 class u_Color :
-	GLUniform1ui
+	GLUniform1i
 {
 public:
 	u_Color( GLShader *shader ) :
-		GLUniform1ui( shader, "u_Color" )
+		GLUniform1i( shader, "u_Color" )
 	{
 	}
 
 	void SetUniform_Color( const Color::Color& color )
 	{
-		this->SetValue( packUnorm4x8( color.ToArray() ) );
+		/* HACK: Store uint32_t as int32_t to be compatible with GLSL 1.20,
+		the GLSL code will convert back to uint32_t. */
+		uint32_t uColor = packUnorm4x8( color.ToArray() );
+		int32_t iColor;
+		memcpy( &iColor, &uColor, sizeof( iColor ) );
+		this->SetValue( iColor );
 	}
 };
 
@@ -3559,10 +3564,10 @@ enum class ColorModulate {
 };
 
 class u_ColorModulateColorGen :
-	GLUniform1ui {
+	GLUniform1i {
 	public:
 	u_ColorModulateColorGen( GLShader* shader ) :
-		GLUniform1ui( shader, "u_ColorModulateColorGen" ) {
+		GLUniform1i( shader, "u_ColorModulateColorGen" ) {
 	}
 
 	void SetUniform_ColorModulateColorGen( colorGen_t colorGen, alphaGen_t alphaGen, bool vertexOverbright = false,
@@ -3629,7 +3634,11 @@ class u_ColorModulateColorGen :
 			This allows to skip the vertex format change */
 			colorModulate |= Util::ordinal( ColorModulate::ALPHA_ADD_ONE );
 		}
-		this->SetValue( colorModulate );
+		/* HACK: Store uint32_t as int32_t to be compatible with GLSL 1.20,
+		the GLSL code will convert back to uint32_t. */
+		int32_t iColorModulate;
+		memcpy( &iColorModulate, &colorModulate, sizeof( iColorModulate ) );
+		this->SetValue( iColorModulate );
 	}
 };
 

src/engine/renderer/glsl_source/common.glsl

@@ -43,33 +43,97 @@ 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 )
 
+// Common functions
+
+vec4 UnpackColor( const in int color )
+{
+#if __VERSION__ > 120
+	uint uColor = color;
+	return unpackUnorm4x8( uColor );
+#else
+	int v = color, m = 0;
+
+	if ( v < 0 )
+	{
+		v = 2147483647 - abs( v ) + 1;
+		m = 128;
+	}
+
+	int a = v / 16777216;
+	v -= a * 16777216;
+	int b = v / 65536;
+	v -= b * 65536;
+	int g = v / 256;
+	v -= g * 256;
+	int r = v;
+	a = a + m;
+
+	return vec4( r, g, b, a ) / 255;
+#endif
+}
+
 /* Bit 0: color * 1
 Bit 1: color * ( -1 )
 Bit 2: color += lightFactor
 Bit 3: alpha * 1
 Bit 4: alpha * ( -1 )
 Bit 5: alpha = 1
+// There should be no bit above.
 Bit 6-9: lightFactor */
 
 float colorModArray[3] = float[3] ( 0.0f, 1.0f, -1.0f );
 
-vec4 ColorModulateToColor( const in uint colorMod ) {
-	vec4 colorModulate = vec4( colorModArray[colorMod & 3] );
-	colorModulate.a = ( colorModArray[( colorMod & 24 ) >> 3] );
+vec4 ColorModulateToColor( const in int colorMod ) {
+#if __VERSION__ > 120
+	int rgbIndex = colorMod & 3;
+	int alphaIndex = ( colorMod & 24 ) >> 3;
+#else
+	int rgbBit0 = colorMod % 2;
+	int rgbBit1 = ( colorMod / 2 ) % 2;
+	int alphaBit0 = ( colorMod / 8 ) % 2;
+	int alphaBit1 = ( colorMod / 16 ) % 2;
+	int rgbIndex = rgbBit0 + ( rgbBit1 * 2 );
+	int alphaIndex = alphaBit0 + ( alphaBit1 * 2 );
+#endif
+
+	vec4 colorModulate = vec4( colorModArray[ rgbIndex ] );
+	colorModulate.a = colorModArray[ alphaIndex ];
 	return colorModulate;
 }
 
-vec4 ColorModulateToColor( const in uint colorMod, const in float lightFactor ) {
-	vec4 colorModulate = vec4( colorModArray[colorMod & 3] + ( ( colorMod & 4 ) >> 2 ) * lightFactor );
-	colorModulate.a = ( colorModArray[( colorMod & 24 ) >> 3] );
+vec4 ColorModulateToColor( const in int colorMod, const in float lightFactor ) {
+#if __VERSION__ > 120
+	int rgbIndex = colorMod & 3;
+	int alphaIndex = ( colorMod & 24 ) >> 3;
+	int hasLight = ( colorMod & 4 ) >> 2;
+#else
+	int rgbBit0 = colorMod % 2;
+	int rgbBit1 = ( colorMod / 2 ) % 2;
+	int hasLight = ( colorMod / 4 ) % 2;
+	int alphaBit0 = ( colorMod / 8 ) % 2;
+	int alphaBit1 = ( colorMod / 16 ) % 2;
+	int rgbIndex = rgbBit0 + ( rgbBit1 * 2 );
+	int alphaIndex = alphaBit0 + ( alphaBit1 * 2 );
+#endif
+
+	vec4 colorModulate = vec4( colorModArray[ rgbIndex ] + ( hasLight * lightFactor ) );
+	colorModulate.a = colorModArray[ alphaIndex ];
 	return colorModulate;
 }
 
-float ColorModulateToLightFactor( const in uint colorMod ) {
+float ColorModulateToLightFactor( const in int colorMod ) {
+#if __VERSION__ > 120
 	return ( colorMod >> 6 ) & 0xF;
+#else
+	return float( colorMod / 64 );
+#endif
 }
 
 // This is used to skip vertex colours if the colorMod doesn't need them
-bool ColorModulateToVertexColor( const in uint colorMod ) {
+bool ColorModulateToVertexColor( const in int colorMod ) {
+#if __VERSION__ > 120
 	return ( colorMod & 32 ) == 32;
+#else
+	return ( colorMod / 32 ) % 2 == 1;
+#endif
 }

src/engine/renderer/glsl_source/fogGlobal_fp.glsl

@@ -22,11 +22,13 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 
 /* fogGlobal_fp.glsl */
 
+#insert common
+
 uniform sampler2D	u_ColorMap; // fog texture
 uniform sampler2D	u_DepthMap;
 
 uniform vec4		u_FogDistanceVector;
-uniform uint u_Color;
+uniform int u_Color;
 uniform mat4		u_UnprojectMatrix;
 
 #if __VERSION__ > 120
@@ -52,5 +54,5 @@ void	main()
 
 	vec4 color = texture2D(u_ColorMap, st);
 
-	outputColor = unpackUnorm4x8( u_Color ) * color;
+	outputColor = UnpackColor( u_Color ) * color;
 }

src/engine/renderer/glsl_source/fogQuake3_vp.glsl

@@ -22,13 +22,14 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 
 /* fogQuake3_vp.glsl */
 
+#insert common
 #insert vertexSimple_vp
 #insert vertexSkinning_vp
 #insert vertexAnimation_vp
 
 uniform float		u_Time;
 
-uniform uint u_Color;
+uniform int u_Color;
 uniform mat4		u_ModelMatrix;
 uniform mat4		u_ModelViewProjectionMatrix;
 
@@ -57,7 +58,7 @@ void	main()
 
 	VertexFetch( position, LB, color, texCoord, lmCoord );
 
-	color = unpackUnorm4x8( u_Color );
+	color = UnpackColor( u_Color );
 
 	DeformVertex( position,
 		      LB.normal,

src/engine/renderer/glsl_source/forwardLighting_vp.glsl

@@ -32,8 +32,8 @@ uniform mat4		u_LightAttenuationMatrix;
 uniform mat4		u_ModelMatrix;
 uniform mat4		u_ModelViewProjectionMatrix;
 
-uniform uint u_ColorModulateColorGen;
-uniform uint u_Color;
+uniform int u_ColorModulateColorGen;
+uniform int u_Color;
 
 uniform float		u_Time;
 
@@ -64,7 +64,7 @@ void	main()
 	VertexFetch( position, LB, color, texCoord, lmCoord);
 
 	// assign color
-    color = color * ColorModulateToColor( u_ColorModulateColorGen ) + unpackUnorm4x8( u_Color );
+	color = color * ColorModulateToColor( u_ColorModulateColorGen ) + UnpackColor( u_Color );
 
 	DeformVertex( position,
 		      LB.normal,

src/engine/renderer/glsl_source/generic_vp.glsl

@@ -36,8 +36,8 @@ uniform vec3		u_ViewOrigin;
 
 uniform float		u_Time;
 
-uniform uint u_ColorModulateColorGen;
-uniform uint u_Color;
+uniform int u_ColorModulateColorGen;
+uniform int u_Color;
 #if defined(USE_TCGEN_ENVIRONMENT)
 uniform mat4		u_ModelMatrix;
 #endif
@@ -70,7 +70,7 @@ void	main()
 	float lightFactor = ColorModulateToLightFactor( u_ColorModulateColorGen );
 	color.a = ColorModulateToVertexColor( u_ColorModulateColorGen ) ? 1.0 : color.a;
 	color = color * ColorModulateToColor( u_ColorModulateColorGen, lightFactor )
-		+ unpackUnorm4x8( u_Color ) * vec4( lightFactor, lightFactor, lightFactor, 1.0 );
+		+ UnpackColor( u_Color ) * vec4( lightFactor, lightFactor, lightFactor, 1.0 );
 
 	DeformVertex( position,
 		      LB.normal,

src/engine/renderer/glsl_source/lightMapping_fp.glsl

@@ -35,7 +35,7 @@ uniform sampler2D	u_GlowMap;
 uniform float		u_AlphaThreshold;
 uniform vec3		u_ViewOrigin;
 
-uniform uint u_ColorModulateColorGen;
+uniform int u_ColorModulateColorGen;
 
 IN(smooth) vec3		var_Position;
 IN(smooth) vec2		var_TexCoords;

src/engine/renderer/glsl_source/lightMapping_vp.glsl

@@ -48,8 +48,8 @@ uniform mat4		u_ModelViewProjectionMatrix;
 
 uniform float		u_Time;
 
-uniform uint u_ColorModulateColorGen;
-uniform uint u_Color;
+uniform int u_ColorModulateColorGen;
+uniform int u_Color;
 
 OUT(smooth) vec3	var_Position;
 OUT(smooth) vec2	var_TexCoords;
@@ -76,7 +76,7 @@ void main()
 
 	VertexFetch(position, LB, color, texCoord, lmCoord);
 
-	color = color * ColorModulateToColor( u_ColorModulateColorGen ) + unpackUnorm4x8( u_Color );
+	color = color * ColorModulateToColor( u_ColorModulateColorGen ) + UnpackColor( u_Color );
 
 	DeformVertex(position, LB.normal, texCoord, color, u_Time);
 

src/engine/renderer/glsl_source/liquid_fp.glsl

@@ -34,7 +34,7 @@ uniform sampler2D	u_DepthMap;
 
 uniform vec3		u_ViewOrigin;
 
-uniform uint u_ColorModulateColorGen;
+uniform int u_ColorModulateColorGen;
 
 uniform float		u_FogDensity;
 uniform vec3		u_FogColor;

src/engine/renderer/glsl_source/shadowFill_vp.glsl

@@ -22,11 +22,12 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 
 /* shadowFill_vp.glsl */
 
+#insert common
 #insert vertexSimple_vp
 #insert vertexSkinning_vp
 #insert vertexAnimation_vp
 
-uniform uint		u_Color;
+uniform int u_Color;
 
 uniform mat3x2		u_TextureMatrix;
 uniform mat4		u_ModelMatrix;
@@ -73,5 +74,5 @@ void	main()
 	var_TexCoords = (u_TextureMatrix * vec3(texCoord, 1.0)).st;
 
 	// assign color
-	var_Color = unpackUnorm4x8( u_Color );
+	var_Color = UnpackColor( u_Color );
 }