Shader: Add support for pow intrinsic

include/Nazara/Shader/Ast/Enums.hpp

@@ -93,6 +93,7 @@ namespace Nz
 			Length = 3,
 			Max = 4,
 			Min = 5,
+			Pow = 6,
 			SampleTexture = 2,
 		};
 

src/Nazara/Shader/Ast/SanitizeVisitor.cpp

@@ -59,9 +59,10 @@ namespace Nz::ShaderAst
 		{
 			RegisterIntrinsic("cross", IntrinsicType::CrossProduct);
 			RegisterIntrinsic("dot", IntrinsicType::DotProduct);
+			RegisterIntrinsic("length", IntrinsicType::Length);
 			RegisterIntrinsic("max", IntrinsicType::Max);
 			RegisterIntrinsic("min", IntrinsicType::Min);
-			RegisterIntrinsic("length", IntrinsicType::Length);
+			RegisterIntrinsic("pow", IntrinsicType::Pow);
 
 			// Collect function name and their types
 			if (nodePtr->GetType() == NodeType::MultiStatement)
@@ -1289,6 +1290,7 @@ namespace Nz::ShaderAst
 			case IntrinsicType::DotProduct:
 			case IntrinsicType::Max:
 			case IntrinsicType::Min:
+			case IntrinsicType::Pow:
 			{
 				if (node.parameters.size() != 2)
 					throw AstError { "Expected two parameters" };
@@ -1379,6 +1381,20 @@ namespace Nz::ShaderAst
 				break;
 			}
 
+			case IntrinsicType::Pow:
+			{
+				const ExpressionType& type = GetExpressionType(*node.parameters.front());
+				if (!IsPrimitiveType(type) && !IsVectorType(type))
+					throw AstError{ "pow only works with primitive and vector types" };
+
+				if ((IsPrimitiveType(type) && std::get<PrimitiveType>(type) != PrimitiveType::Float32) ||
+					(IsVectorType(type) && std::get<VectorType>(type).type != PrimitiveType::Float32))
+					throw AstError{ "pow only works with floating-point primitive or vectors" };
+
+				node.cachedExpressionType = type;
+				break;
+			}
+
 			case IntrinsicType::SampleTexture:
 			{
 				node.cachedExpressionType = VectorType{ 4, std::get<SamplerType>(GetExpressionType(*node.parameters.front())).sampledType };

src/Nazara/Shader/GlslWriter.cpp

@@ -1020,6 +1020,10 @@ namespace Nz
 				Append("min");
 				break;
 
+			case ShaderAst::IntrinsicType::Pow:
+				Append("pow");
+				break;
+
 			case ShaderAst::IntrinsicType::SampleTexture:
 				Append("texture");
 				break;

src/Nazara/Shader/SpirvAstVisitor.cpp

@@ -799,6 +799,31 @@ namespace Nz
 				break;
 			}
 
+			case ShaderAst::IntrinsicType::Pow:
+			{
+				UInt32 glslInstructionSet = m_writer.GetExtendedInstructionSet("GLSL.std.450");
+
+				const ShaderAst::ExpressionType& parameterType = GetExpressionType(*node.parameters[0]);
+				assert(IsPrimitiveType(parameterType) || IsVectorType(parameterType));
+				UInt32 typeId = m_writer.GetTypeId(parameterType);
+
+				ShaderAst::PrimitiveType basicType;
+				if (IsPrimitiveType(parameterType))
+					basicType = std::get<ShaderAst::PrimitiveType>(parameterType);
+				else if (IsVectorType(parameterType))
+					basicType = std::get<ShaderAst::VectorType>(parameterType).type;
+				else
+					throw std::runtime_error("unexpected expression type");
+
+				UInt32 firstParam = EvaluateExpression(node.parameters[0]);
+				UInt32 secondParam = EvaluateExpression(node.parameters[1]);
+				UInt32 resultId = m_writer.AllocateResultId();
+
+				m_currentBlock->Append(SpirvOp::OpExtInst, typeId, resultId, glslInstructionSet, GLSLstd450Pow, firstParam, secondParam);
+				PushResultId(resultId);
+				break;
+			}
+
 			case ShaderAst::IntrinsicType::SampleTexture:
 			{
 				UInt32 typeId = m_writer.GetTypeId(ShaderAst::VectorType{4, ShaderAst::PrimitiveType::Float32});

src/Nazara/Shader/SpirvWriter.cpp

@@ -324,6 +324,7 @@ namespace Nz
 						case ShaderAst::IntrinsicType::Length:
 						case ShaderAst::IntrinsicType::Max:
 						case ShaderAst::IntrinsicType::Min:
+						case ShaderAst::IntrinsicType::Pow:
 							extInsts.emplace("GLSL.std.450");
 							break;