#6052: Adjust parser to treat mirrorRenderMap dimensions optional.

The token must not be exhausted when looking for the dimensions.

libs/string/convert.h

@@ -257,6 +257,20 @@ inline bool tryConvertToFloat(const std::string& src, float& value)
     return lastChar != firstChar;
 }
 
+// Attempts to convert the given source string to an int value,
+// returning true on success. The value reference will then be holding
+// the resulting int value (or 0 in case of failure).
+// Note: this is using the exception-less std::strtol, making it preferable
+// over the string::convert<int> method (in certain hot code paths).
+inline bool tryConvertToInt(const std::string& src, int& value)
+{
+    char* lastChar;
+    auto* firstChar = src.c_str();
+    value = static_cast<int>(std::strtol(firstChar, &lastChar, 10));
+
+    return lastChar != firstChar;
+}
+
 // Convert the given type to a std::string
 template<typename Src> 
 inline std::string to_string(const Src& value)

radiantcore/shaders/ShaderTemplate.cpp

@@ -598,10 +598,8 @@ bool ShaderTemplate::parseBlendMaps(parser::DefTokeniser& tokeniser, const std::
 {
     if (token == "map")
     {
-        _currentLayer->setBindableTexture(
-            MapExpression::createForToken(tokeniser)
-        );
-        _currentLayer->setMapType(IShaderLayer::MapType::Map);
+        _currentLayer->setBindableTexture(MapExpression::createForToken(tokeniser));
+        // Don't reset the map type of this layer, "map" can occur in multiple scenarios
     }
     else if (token == "cameracubemap")
     {
@@ -663,35 +661,13 @@ bool ShaderTemplate::parseBlendMaps(parser::DefTokeniser& tokeniser, const std::
 	else if (token == "remoterendermap")
 	{
         _currentLayer->setMapType(IShaderLayer::MapType::RemoteRenderMap);
-
-		try
-		{
-			auto width = std::stoi(tokeniser.nextToken());
-            auto height = std::stoi(tokeniser.nextToken());
-            _currentLayer->setRenderMapSize(Vector2(width, height));
-		}
-		catch (std::logic_error& e)
-		{
-			rWarning() << "Error parsing remoteRenderMap. Expected two integers: " 
-				<< e.what() << std::endl;
-		}
+        parseRenderMapSize(tokeniser, true); // remoteRenderMap dimension is mandatory
 	}
 	else if (token == "mirrorrendermap")
 	{
         _currentLayer->setMapType(IShaderLayer::MapType::MirrorRenderMap);
         _currentLayer->setTexGenType(IShaderLayer::TexGenType::TEXGEN_SCREEN);
-
-		try
-		{
-            auto width = std::stoi(tokeniser.nextToken());
-            auto height = std::stoi(tokeniser.nextToken());
-            _currentLayer->setRenderMapSize(Vector2(width, height));
-		}
-		catch (std::invalid_argument& e)
-		{
-			rWarning() << "Error parsing mirrorRenderMap. Expected two integers: "
-				<< e.what() << std::endl;
-		}
+        parseRenderMapSize(tokeniser, true); // mirrorRenderMap dimension is optional
 	}
 	else
 	{
@@ -701,6 +677,35 @@ bool ShaderTemplate::parseBlendMaps(parser::DefTokeniser& tokeniser, const std::
 	return true;
 }
 
+void ShaderTemplate::parseRenderMapSize(parser::DefTokeniser& tokeniser, bool optional)
+{
+    // Parse the dimensions without immediately exhausting the upcoming token
+    // Will not exhaust the tokens that are not convertible to an integer
+    int width;
+    if (string::tryConvertToInt(tokeniser.peek(), width))
+    {
+        tokeniser.nextToken(); // exhaust
+    }
+    else if (!optional)
+    {
+        rWarning() << "Error parsing render map width. Expected two integers." << std::endl;
+        return;
+    }
+
+    int height;
+    if (string::tryConvertToInt(tokeniser.peek(), height))
+    {
+        tokeniser.nextToken(); // exhaust
+    }
+    else if (!optional)
+    {
+        rWarning() << "Error parsing render map height. Expected two integers." << std::endl;
+        return;
+    }
+
+    _currentLayer->setRenderMapSize({ width, height });
+}
+
 bool ShaderTemplate::parseStageModifiers(parser::DefTokeniser& tokeniser,
                                          const std::string& token)
 {

radiantcore/shaders/ShaderTemplate.h

@@ -551,6 +551,7 @@ class ShaderTemplate final :
 	bool parseMaterialType(parser::DefTokeniser&, const std::string&);
 	bool parseCondition(parser::DefTokeniser&, const std::string&);
 	IShaderExpression::Ptr parseSingleExpressionTerm(parser::DefTokeniser& tokeniser);
+	void parseRenderMapSize(parser::DefTokeniser&, bool optional);
 
 	bool saveLayer();
     void determineCoverage();