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src/Nazara/Renderer/GlslWriter.cpp

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+// Copyright (C) 2015 Jérôme Leclercq
+// This file is part of the "Nazara Engine - Renderer module"
+// For conditions of distribution and use, see copyright notice in Config.hpp
+
+#include <Nazara/Renderer/GlslWriter.hpp>
+#include <Nazara/Core/CallOnExit.hpp>
+#include <Nazara/Renderer/Debug.hpp>
+
+namespace Nz
+{
+	GlslWriter::GlslWriter() :
+	m_currentState(nullptr)
+	{
+	}
+
+	String GlslWriter::Generate(const ShaderAst::StatementPtr& node)
+	{
+		State state;
+		m_currentState = &state;
+		CallOnExit onExit([this]()
+		{
+			m_currentState = nullptr;
+		});
+
+		node->Register(*this);
+
+		for (const auto& pair : state.m_variables)
+		{
+			Append(pair.first);
+			Append(" ");
+			Append(pair.second);
+			AppendLine(";");
+		}
+
+		AppendLine();
+
+		Function entryPoint;
+		entryPoint.name = "main"; //< GLSL has only one entry point name possible
+		entryPoint.node = node;
+		entryPoint.retType = ShaderAst::ExpressionType::None;
+
+		AppendFunction(entryPoint);
+
+		return state.stream;
+	}
+
+	void GlslWriter::RegisterFunction(const String& name, ShaderAst::StatementPtr statement, std::initializer_list<ShaderAst::VariablePtr> parameters, ShaderAst::ExpressionType retType)
+	{
+		Function func;
+		func.retType = retType;
+		func.name = name;
+		func.node = std::move(statement);
+		func.parameters.assign(parameters);
+
+		m_functions[name] = std::move(func);
+	}
+
+	void GlslWriter::RegisterVariable(const String& name, ShaderAst::ExpressionType type)
+	{
+		NazaraAssert(m_currentState, "This function should only be called while processing an AST");
+
+		m_currentState->m_variables.insert(std::make_pair(type, name));
+	}
+
+	void GlslWriter::Write(const ShaderAst::NodePtr& node)
+	{
+		node->Visit(*this);
+	}
+
+	void GlslWriter::Write(const ShaderAst::AssignOp& node)
+	{
+		Write(node.variable);
+
+		switch (node.op)
+		{
+			case ShaderAst::AssignType::Simple:
+				Append(" = ");
+				break;
+		}
+
+		Write(node.right);
+	}
+
+	void GlslWriter::Write(const ShaderAst::Branch& node)
+	{
+		bool first = true;
+		for (const auto& statement : node.condStatements)
+		{
+			if (!first)
+				Append("else ");
+
+			Append("if (");
+			Write(statement.condition);
+			AppendLine(")");
+
+			EnterScope();
+				Write(statement.statement);
+			LeaveScope();
+
+			first = false;
+		}
+
+		if (node.elseStatement)
+		{
+			AppendLine("else");
+
+			EnterScope();
+				Write(node.elseStatement);
+			LeaveScope();
+		}
+	}
+
+	void GlslWriter::Write(const ShaderAst::BinaryOp& node)
+	{
+		Write(node.left);
+
+		switch (node.op)
+		{
+			case ShaderAst::BinaryType::Add:
+				Append(" + ");
+				break;
+			case ShaderAst::BinaryType::Substract:
+				Append(" - ");
+				break;
+			case ShaderAst::BinaryType::Multiply:
+				Append(" * ");
+				break;
+			case ShaderAst::BinaryType::Divide:
+				Append(" / ");
+				break;
+			case ShaderAst::BinaryType::Equality:
+				Append(" == ");
+				break;
+		}
+
+		Write(node.right);
+	}
+
+	void GlslWriter::Write(const ShaderAst::Constant& node)
+	{
+		switch (node.exprType)
+		{
+			case ShaderAst::ExpressionType::Float1:
+				Append(String::Format("%F", node.values.vec1));
+				break;
+		}
+	}
+
+	void GlslWriter::Write(const ShaderAst::ExpressionStatement& node)
+	{
+		Write(node.expression);
+		Append(";");
+	}
+
+	void GlslWriter::Write(const ShaderAst::StatementBlock& node)
+	{
+		bool first = true;
+		for (const ShaderAst::StatementPtr& statement : node.statements)
+		{
+			if (!first)
+				AppendLine();
+
+			Write(statement);
+
+			first = false;
+		}
+	}
+
+	void GlslWriter::Write(const ShaderAst::Variable& node)
+	{
+		Append(node.name);
+	}
+
+	void GlslWriter::Append(ShaderAst::ExpressionType type)
+	{
+		switch (type)
+		{
+			case ShaderAst::ExpressionType::Float1:
+				Append("float");
+				break;
+			case ShaderAst::ExpressionType::Float2:
+				Append("vec2");
+				break;
+			case ShaderAst::ExpressionType::Float3:
+				Append("vec3");
+				break;
+			case ShaderAst::ExpressionType::Float4:
+				Append("vec4");
+				break;
+			case ShaderAst::ExpressionType::None:
+				Append("void");
+				break;
+		}
+	}
+
+	void GlslWriter::Append(const String& txt)
+	{
+		NazaraAssert(m_currentState, "This function should only be called while processing an AST");
+
+		m_currentState->stream << txt;
+	}
+
+	void GlslWriter::AppendFunction(const Function& func)
+	{
+		NazaraAssert(m_currentState, "This function should only be called while processing an AST");
+
+		Append(func.retType);
+
+		m_currentState->stream << ' ';
+		Append(func.name);
+
+		m_currentState->stream << '(';
+		for (std::size_t i = 0; i < func.parameters.size(); ++i)
+		{
+			if (i != 0)
+				m_currentState->stream << ", ";
+
+			Append(func.parameters[i]->type);
+			m_currentState->stream << ' ';
+			Append(func.parameters[i]->name);
+		}
+		m_currentState->stream << ")\n";
+
+		EnterScope();
+			Write(func.node);
+		LeaveScope();
+	}
+
+	void GlslWriter::AppendLine(const String& txt)
+	{
+		NazaraAssert(m_currentState, "This function should only be called while processing an AST");
+
+		m_currentState->stream << txt << '\n' << String(m_currentState->indentLevel, '\t');
+	}
+
+	void GlslWriter::EnterScope()
+	{
+		NazaraAssert(m_currentState, "This function should only be called while processing an AST");
+
+		m_currentState->indentLevel++;
+		AppendLine("{");
+	}
+
+	void GlslWriter::LeaveScope()
+	{
+		NazaraAssert(m_currentState, "This function should only be called while processing an AST");
+
+		m_currentState->indentLevel--;
+		AppendLine();
+		AppendLine("}");
+	}
+
+}