Big SpirVWriter refactor

src/Nazara/Shader/SpirvExpressionStore.cpp

@@ -0,0 +1,104 @@
+// Copyright (C) 2020 Jérôme Leclercq
+// This file is part of the "Nazara Engine - Shader generator"
+// For conditions of distribution and use, see copyright notice in Config.hpp
+
+#include <Nazara/Shader/SpirvExpressionStore.hpp>
+#include <Nazara/Shader/SpirvSection.hpp>
+#include <Nazara/Shader/SpirvWriter.hpp>
+#include <Nazara/Shader/Debug.hpp>
+
+namespace Nz
+{
+	namespace
+	{
+		template<class... Ts> struct overloaded : Ts... { using Ts::operator()...; };
+		template<class... Ts> overloaded(Ts...)->overloaded<Ts...>;
+	}
+
+	void SpirvExpressionStore::Store(const ShaderNodes::ExpressionPtr& node, UInt32 resultId)
+	{
+		Visit(node);
+		
+		std::visit(overloaded
+		{
+			[&](const Pointer& pointer)
+			{
+				m_writer.GetInstructions().Append(SpirvOp::OpStore, pointer.resultId, resultId);
+			},
+			[&](const LocalVar& value)
+			{
+				m_writer.WriteLocalVariable(value.varName, resultId);
+			},
+			[this](std::monostate)
+			{
+				throw std::runtime_error("an internal error occurred");
+			}
+		}, m_value);
+	}
+
+	void SpirvExpressionStore::Visit(ShaderNodes::AccessMember& node)
+	{
+		Visit(node.structExpr);
+
+		std::visit(overloaded
+		{
+			[&](const Pointer& pointer) -> UInt32
+			{
+				UInt32 resultId = m_writer.AllocateResultId();
+				UInt32 pointerType = m_writer.RegisterPointerType(node.exprType, pointer.storage); //< FIXME
+				UInt32 typeId = m_writer.GetTypeId(node.exprType);
+
+				m_writer.GetInstructions().AppendVariadic(SpirvOp::OpAccessChain, [&](const auto& appender)
+				{
+					appender(pointerType);
+					appender(resultId);
+					appender(pointer.resultId);
+
+					for (std::size_t index : node.memberIndices)
+						appender(m_writer.GetConstantId(Int32(index)));
+				});
+
+				m_value = Pointer{ pointer.storage, resultId };
+
+				return resultId;
+			},
+			[&](const LocalVar& value) -> UInt32
+			{
+				throw std::runtime_error("not yet implemented");
+			},
+			[this](std::monostate) -> UInt32
+			{
+				throw std::runtime_error("an internal error occurred");
+			}
+		}, m_value);
+	}
+
+	void SpirvExpressionStore::Visit(ShaderNodes::Identifier& node)
+	{
+		Visit(node.var);
+	}
+
+	void SpirvExpressionStore::Visit(ShaderNodes::SwizzleOp& node)
+	{
+		throw std::runtime_error("not yet implemented");
+	}
+
+	void SpirvExpressionStore::Visit(ShaderNodes::BuiltinVariable& var)
+	{
+		const auto& outputVar = m_writer.GetBuiltinVariable(var.entry);
+
+		m_value = Pointer{ SpirvStorageClass::Output, outputVar.varId };
+	}
+
+	void SpirvExpressionStore::Visit(ShaderNodes::LocalVariable& var)
+	{
+		m_value = LocalVar{ var.name };
+	}
+
+	void SpirvExpressionStore::Visit(ShaderNodes::OutputVariable& var)
+	{
+		const auto& outputVar = m_writer.GetOutputVariable(var.name);
+
+		m_value = Pointer{ SpirvStorageClass::Output, outputVar.varId };
+	}
+}