Shader/ShaderLang: Add type inference for variable declaration

examples/RenderTest/main.cpp

@@ -45,8 +45,8 @@ struct FragOut
 [[entry(frag)]]
 fn main(fragIn: VertOut) -> FragOut
 {
-	let lightDir: vec3<f32> = vec3<f32>(0.0, -0.707, 0.707);
+	let lightDir = vec3<f32>(0.0, -0.707, 0.707);
-	let lightFactor: f32 = dot(fragIn.normal, lightDir);
+	let lightFactor = dot(fragIn.normal, lightDir);
 
 	let fragOut: FragOut;
 	fragOut.color = lightFactor * tex.Sample(fragIn.uv);

include/Nazara/Shader/ShaderAstValidator.hpp

@@ -49,6 +49,7 @@ namespace Nz::ShaderAst
 			void Visit(DeclareExternalStatement& node) override;
 			void Visit(DeclareFunctionStatement& node) override;
 			void Visit(DeclareStructStatement& node) override;
+			void Visit(DeclareVariableStatement& node) override;
 			void Visit(ExpressionStatement& node) override;
 			void Visit(MultiStatement& node) override;
 

include/Nazara/Shader/ShaderBuilder.hpp

@@ -70,6 +70,7 @@ namespace Nz::ShaderBuilder
 
 		struct DeclareVariable
 		{
+			inline std::unique_ptr<ShaderAst::DeclareVariableStatement> operator()(std::string name, ShaderAst::ExpressionPtr initialValue) const;
 			inline std::unique_ptr<ShaderAst::DeclareVariableStatement> operator()(std::string name, ShaderAst::ExpressionType type, ShaderAst::ExpressionPtr initialValue = nullptr) const;
 		};
 

include/Nazara/Shader/ShaderBuilder.inl

@@ -128,6 +128,15 @@ namespace Nz::ShaderBuilder
 		return declareStructNode;
 	}
 
+	inline std::unique_ptr<ShaderAst::DeclareVariableStatement> Nz::ShaderBuilder::Impl::DeclareVariable::operator()(std::string name, ShaderAst::ExpressionPtr initialValue) const
+	{
+		auto declareVariableNode = std::make_unique<ShaderAst::DeclareVariableStatement>();
+		declareVariableNode->varName = std::move(name);
+		declareVariableNode->initialExpression = std::move(initialValue);
+
+		return declareVariableNode;
+	}
+
 	inline std::unique_ptr<ShaderAst::DeclareVariableStatement> Nz::ShaderBuilder::Impl::DeclareVariable::operator()(std::string name, ShaderAst::ExpressionType type, ShaderAst::ExpressionPtr initialValue) const
 	{
 		auto declareVariableNode = std::make_unique<ShaderAst::DeclareVariableStatement>();

src/Nazara/Shader/ShaderAstValidator.cpp

@@ -594,6 +594,21 @@ namespace Nz::ShaderAst
 		AstScopedVisitor::Visit(node);
 	}
 
+	void AstValidator::Visit(DeclareVariableStatement& node)
+	{
+		if (IsNoType(node.varType))
+		{
+			if (!node.initialExpression)
+				throw AstError{ "variable must either have a type or an initial value" };
+
+			node.initialExpression->Visit(*this);
+
+			node.varType = GetExpressionType(*node.initialExpression);
+		}
+
+		AstScopedVisitor::Visit(node);
+	}
+
 	void AstValidator::Visit(ExpressionStatement& node)
 	{
 		MandatoryExpr(node.expression);

src/Nazara/Shader/ShaderLangParser.cpp

@@ -638,14 +638,18 @@ namespace Nz::ShaderLang
 		std::string variableName = ParseIdentifierAsName();
 		RegisterVariable(variableName);
 
-		Expect(Advance(), TokenType::Colon);
+		ShaderAst::ExpressionType variableType = ShaderAst::NoType{};
+		if (Peek().type == TokenType::Colon)
+		{
+			Expect(Advance(), TokenType::Colon);
 
-		ShaderAst::ExpressionType variableType = ParseType();
+			variableType = ParseType();
+		}
 
 		ShaderAst::ExpressionPtr expression;
-		if (Peek().type == TokenType::Assign)
+		if (IsNoType(variableType) || Peek().type == TokenType::Assign)
 		{
-			Consume();
+			Expect(Advance(), TokenType::Assign);
 			expression = ParseExpression();
 		}