renderer: simplify builtin color image name parsing, rename as $name, forget about unused aliases

Author: illwieckz

src/engine/renderer/tr_image.cpp

@@ -2764,34 +2764,34 @@ void R_CreateBuiltinImages()
 	imageParams.filterType = filterType_t::FT_LINEAR;
 	imageParams.wrapType = wrapTypeEnum_t::WT_REPEAT;
 
-	tr.whiteImage = R_CreateImage( "_white", ( const byte ** ) &dataPtr, 1, 1, 1, imageParams );
+	tr.whiteImage = R_CreateImage( "$white", ( const byte ** ) &dataPtr, 1, 1, 1, imageParams );
 
 	// we use a solid black image instead of disabling texturing
 	memset( data, 0, sizeof( data ) );
 
-	tr.blackImage = R_CreateImage( "_black", ( const byte ** ) &dataPtr, 1, 1, 1, imageParams );
+	tr.blackImage = R_CreateImage( "$black", ( const byte ** ) &dataPtr, 1, 1, 1, imageParams );
 
 	// red
 	Vector4Set( data, 255, 0, 0, 255 );
 
-	tr.redImage = R_CreateImage( "_red", ( const byte ** ) &dataPtr, 1, 1, 1, imageParams );
+	tr.redImage = R_CreateImage( "$red", ( const byte ** ) &dataPtr, 1, 1, 1, imageParams );
 
 	// green
 	Vector4Set( data, 0, 255, 0, 255 );
 
-	tr.greenImage = R_CreateImage( "_green", ( const byte ** ) &dataPtr, 1, 1, 1, imageParams );
+	tr.greenImage = R_CreateImage( "$green", ( const byte ** ) &dataPtr, 1, 1, 1, imageParams );
 
 	// blue
 	Vector4Set( data, 0, 0, 255, 255 );
 
-	tr.blueImage = R_CreateImage( "_blue", ( const byte ** ) &dataPtr, 1, 1, 1, imageParams );
+	tr.blueImage = R_CreateImage( "$blue", ( const byte ** ) &dataPtr, 1, 1, 1, imageParams );
 
 	// generate a default normalmap with a fully opaque heightmap (no displacement)
 	Vector4Set( data, 128, 128, 255, 255 );
 
 	imageParams.bits = IF_NOPICMIP | IF_NORMALMAP;
 
-	tr.flatImage = R_CreateImage( "_flat", ( const byte ** ) &dataPtr, 1, 1, 1, imageParams );
+	tr.flatImage = R_CreateImage( "$flat", ( const byte ** ) &dataPtr, 1, 1, 1, imageParams );
 
 	imageParams.bits = IF_NOPICMIP;
 	imageParams.wrapType = wrapTypeEnum_t::WT_CLAMP;

src/engine/renderer/tr_shader.cpp

@@ -1434,24 +1434,19 @@ static bool LoadMap( shaderStage_t *stage, const char *buffer, stageType_t type,
 		return true;
 	}
 
-	if ( !Q_stricmp( token, "$whiteimage" ) || !Q_stricmp( token, "$white" ) || !Q_stricmp( token, "_white" ) ||
-	     !Q_stricmp( token, "*white" ) )
+	// Quake III backward compatibility.
+	if ( !Q_stricmp( token, "$whiteimage" ) || !Q_stricmp( token, "*white" ) )
 	{
 		stage->bundle[ bundleIndex ].image[ 0 ] = tr.whiteImage;
 		return true;
 	}
-	else if ( !Q_stricmp( token, "$blackimage" ) || !Q_stricmp( token, "$black" ) || !Q_stricmp( token, "_black" ) ||
-	          !Q_stricmp( token, "*black" ) )
+
+	// Other engine compatibility (old XeaL, QFusion…)
+	if ( !Q_stricmp( token, "$blackimage" ) || !Q_stricmp( token, "*black" ) )
 	{
 		stage->bundle[ bundleIndex ].image[ 0 ] = tr.blackImage;
 		return true;
 	}
-	else if ( !Q_stricmp( token, "$flatimage" ) || !Q_stricmp( token, "$flat" ) || !Q_stricmp( token, "_flat" ) ||
-	          !Q_stricmp( token, "*flat" ) )
-	{
-		stage->bundle[ bundleIndex ].image[ 0 ] = tr.flatImage;
-		return true;
-	}
 
 	else if ( !Q_stricmp( token, "$lightmap" ) )
 	{