ParseShader: load extra textures the DarkPlaces way if r_dpMaterial on

 if r_dpMaterial set to on,  load extra textures the DarkPlaces way
 i.e. look for extra files with special suffixes like _norm or _gloss

Author: illwieckz

src/engine/renderer/tr_shader.cpp

@@ -49,6 +49,14 @@ static cullType_t    implicitCullType;
 
 static char          whenTokens[ MAX_STRING_CHARS ];
 
+// DarkPlaces material compatibility
+static Cvar::Cvar<bool> r_dpMaterial("r_dpMaterial", "Enable DarkPlaces material compatibility.", Cvar::NONE, false);
+
+static bool UseDpMaterial()
+{
+	return *r_dpMaterial;
+}
+
 /*
 ================
 return a hash value for the filename
@@ -1479,6 +1487,58 @@ static bool ParseClampType( char *token, wrapType_t *clamp )
 	return true;
 }
 
+/*
+===================
+FindMapInStage
+===================
+*/
+static bool FindMapInStage( const char **text, char *buffer, int bufferlen )
+{
+	char *token;
+	bool foundMap;
+
+	while ( true )
+	{
+		token = COM_ParseExt2( text, true );
+
+		if ( token[ 0 ] == '\0' )
+		{
+			// the real parser will complain about it
+			// no need to print twice the same warning
+			return false;
+		}
+		if ( token[ 0 ] == '}' )
+		{
+			break;
+		}
+		else if ( !Q_stricmp( token, "stage" ) )
+		{
+			return false;
+		}
+		else if ( !Q_stricmp( token, "map" ) )
+		{
+			if ( !ParseMap( text, buffer, bufferlen ) )
+			{
+				return false;
+			}
+			foundMap = true;
+		}
+	}
+
+	if ( foundMap )
+	{
+		if ( buffer[0] == '*'
+			|| buffer[0] == '_'
+			|| buffer[0] == '$' )
+		{
+			return false;
+		}
+		return true;
+	}
+
+	return false;
+}
+
 /*
 ===================
 ParseStage
@@ -3100,6 +3160,22 @@ static void ParseLightFalloffImage( shaderStage_t *stage, const char **text )
 	}
 }
 
+struct extraMapParser_t
+{
+	const char *suffix;
+	const char *description;
+	void ( *parser ) ( shaderStage_t*, const char** );
+};
+
+static const extraMapParser_t extraMapParsers[] =
+{
+	{ "_norm",    "normal map",     ParseNormalMap     },
+	{ "_gloss",   "specular map",   ParseSpecularMap   },
+	{ "_glow",    "glow map",       ParseGlowMap       },
+};
+
+static int numExtraMapParsers = ARRAY_LEN( extraMapParsers );
+
 /*
 =================
 ParseShader
@@ -3144,6 +3220,55 @@ static bool ParseShader( const char *_text )
 		// stage definition
 		else if ( token[ 0 ] == '{' )
 		{
+			if ( UseDpMaterial() )
+			{
+				// DarkPlaces material compatibility
+				// look if the stage to be parsed has a map keyword without a stage keyword
+				// look for extra maps based on their suffixes
+				// if they exist, load them
+				// and tell the stage to be parsed is a diffuseMap one just before parsing it
+				const char **safeTextPointer;
+				const char *_safeTextPointer;
+				_safeTextPointer = *text;
+				safeTextPointer = &_safeTextPointer;
+
+				char colorMapName[ 1024 ] = "";
+				bool foundMap = FindMapInStage( safeTextPointer, colorMapName, sizeof( colorMapName ) );
+				if (foundMap) {
+					const char *prefix; // not used but required by R_FindImageLoader
+					const char *extraMapName;
+					char colorMapBaseName[ MAX_QPATH ];
+					bool foundExtraMap = false;
+
+					Log::Debug( "looking for extra maps for color map: '%s'", colorMapName );
+					COM_StripExtension3( colorMapName, colorMapBaseName, MAX_QPATH );
+
+					int i;
+					for ( i = 0; i < numExtraMapParsers; i++ )
+					{
+						if ( s >= ( MAX_SHADER_STAGES - 1 ) )
+						{
+							Log::Warn( "too many extra stages in shader %s", shader.name );
+							return false;
+						}
+
+						extraMapName = va( "%s%s", colorMapBaseName, extraMapParsers[ i ].suffix );
+						if( R_FindImageLoader( (char*) extraMapName, &prefix ) >= 0 )
+						{
+							foundExtraMap = true;
+							Log::Debug( "found extra %s '%s'", extraMapParsers[ i ].description, extraMapName );
+							extraMapParsers[ i ].parser( &stages[ s ], &extraMapName );
+							s++;
+						}
+					}
+
+					if ( foundExtraMap )
+					{
+						stages[ s ].type = stageType_t::ST_DIFFUSEMAP;
+					}
+				}
+			}
+
 			if ( s >= ( MAX_SHADER_STAGES - 1 ) )
 			{
 				Log::Warn("too many stages in shader %s", shader.name );