Shader: Add support for custom functions calls (and better handle intrinsics)

src/Nazara/Shader/ShaderLangParser.cpp

@@ -18,14 +18,6 @@ namespace Nz::ShaderLang
 			{ "f32",  ShaderAst::PrimitiveType::Float32 },
 			{ "u32",  ShaderAst::PrimitiveType::UInt32 }
 		};
-
-		std::unordered_map<std::string, ShaderAst::IntrinsicType> s_identifierToIntrinsic = {
-			{ "cross", ShaderAst::IntrinsicType::CrossProduct },
-			{ "dot", ShaderAst::IntrinsicType::DotProduct },
-			{ "max", ShaderAst::IntrinsicType::Max },
-			{ "min", ShaderAst::IntrinsicType::Min },
-			{ "length", ShaderAst::IntrinsicType::Length },
-		};
 
 		std::unordered_map<std::string, ShaderAst::AttributeType> s_identifierToAttributeType = {
 			{ "binding",  ShaderAst::AttributeType::Binding  },
@@ -137,14 +129,19 @@ namespace Nz::ShaderLang
 		m_context->tokenIndex += count;
 	}
 
-	ShaderAst::ExpressionType Parser::DecodeType(const std::string& identifier)
+	std::optional<ShaderAst::ExpressionType> Parser::DecodeType(const std::string& identifier)
 	{
-		if (auto it = s_identifierToBasicType.find(identifier); it != s_identifierToBasicType.end())
+		if (auto it = s_identifierToBasicType.find(identifier); it != s_identifierToBasicType.end())
+		{
+			Consume();
 			return it->second;
+		}
 
 		//FIXME: Handle this better
 		if (identifier == "mat4")
-		{
+		{
+			Consume();
+
 			ShaderAst::MatrixType matrixType;
 			matrixType.columnCount = 4;
 			matrixType.rowCount = 4;
@@ -156,7 +153,9 @@ namespace Nz::ShaderLang
 			return matrixType;
 		}
 		else if (identifier == "sampler2D")
-		{
+		{
+			Consume();
+
 			ShaderAst::SamplerType samplerType;
 			samplerType.dim = ImageType_2D;
 
@@ -167,7 +166,9 @@ namespace Nz::ShaderLang
 			return samplerType;
 		}
 		else if (identifier == "uniform")
-		{
+		{
+			Consume();
+
 			ShaderAst::UniformType uniformType;
 
 			Expect(Advance(), TokenType::LessThan); //< '<'
@@ -177,7 +178,9 @@ namespace Nz::ShaderLang
 			return uniformType;
 		}
 		else if (identifier == "vec2")
-		{
+		{
+			Consume();
+
 			ShaderAst::VectorType vectorType;
 			vectorType.componentCount = 2;
 
@@ -188,7 +191,9 @@ namespace Nz::ShaderLang
 			return vectorType;
 		}
 		else if (identifier == "vec3")
-		{
+		{
+			Consume();
+
 			ShaderAst::VectorType vectorType;
 			vectorType.componentCount = 3;
 
@@ -199,7 +204,9 @@ namespace Nz::ShaderLang
 			return vectorType;
 		}
 		else if (identifier == "vec4")
-		{
+		{
+			Consume();
+
 			ShaderAst::VectorType vectorType;
 			vectorType.componentCount = 4;
 
@@ -208,14 +215,9 @@ namespace Nz::ShaderLang
 			Expect(Advance(), TokenType::GreatherThan); //< '>'
 
 			return vectorType;
-		}
-		else
-		{
-			ShaderAst::IdentifierType identifierType;
-			identifierType.name = identifier;
-
-			return identifierType;
-		}
+		}
+		else
+			return std::nullopt;
 	}
 
 	void Parser::EnterScope()
@@ -873,23 +875,19 @@ namespace Nz::ShaderLang
 			case TokenType::Identifier:
 			{
 				const std::string& identifier = std::get<std::string>(token.data);
-
+
+				// Is it a cast? 
+				std::optional<ShaderAst::ExpressionType> exprType = DecodeType(identifier);
+				if (exprType)
+					return ShaderBuilder::Cast(std::move(*exprType), ParseParameters());
+
 				if (Peek(1).type == TokenType::OpenParenthesis)
-				{
-					if (Peek(1).type == TokenType::OpenParenthesis)
-					{
-						Consume();
-						return ShaderBuilder::Intrinsic(it->second, ParseParameters());
+				{
+					// Function call
+					Consume();
 					return ShaderBuilder::CallFunction(identifier, ParseParameters());
-				}
-
-				if (IsVariableInScope(identifier))
-					return ParseIdentifier();
-
-				Consume();
-
-				ShaderAst::ExpressionType exprType = DecodeType(identifier);
-
+				}
+				else
 					return ParseIdentifier();
 			}
 
@@ -989,10 +987,17 @@ namespace Nz::ShaderLang
 
 			return ShaderAst::NoType{};
 		}
-
+
 		const Token& identifierToken = Expect(Peek(), TokenType::Identifier);
 		const std::string& identifier = std::get<std::string>(identifierToken.data);
-
+
+		auto type = DecodeType(identifier);
+		if (!type)
+		{
+			Consume();
+			return ShaderAst::IdentifierType{ identifier };
+		}
+
 		return *type;
 	}