1 files changed, 71 insertions, 0 deletions
diff --git a/include/RenderBackend/OpenGL/PixelShader.hpp b/include/RenderBackend/OpenGL/PixelShader.hpp
new file mode 100644
index 0000000..3d33155
--- /dev/null
+++ b/include/RenderBackend/OpenGL/PixelShader.hpp
@@ -0,0 +1,71 @@
+#pragma once
+
+#include "../../DataView.hpp"
+#include "ShaderVec.hpp"
+#include <string>
+#include <unordered_map>
+#include <vector>
+#include <stdexcept>
+#include <functional>
+
+namespace amalgine
+{
+    class PixelShaderTooManyAttributes : public std::runtime_error
+    {
+    public:
+        PixelShaderTooManyAttributes(i32 maxPixelAttributes);
+    };
+    
+    class PixelShaderAttributeAlreadyDefined : public std::runtime_error
+    {
+    public:
+        PixelShaderAttributeAlreadyDefined(const std::string &attributeName);
+    };
+    
+    class PixelShaderInvalidAttributeName : public std::runtime_error
+    {
+    public:
+        PixelShaderInvalidAttributeName(const std::string &attributeName);
+    };
+    
+    class PixelShaderFunctionAlreadyDefined : public std::runtime_error
+    {
+    public:
+        PixelShaderFunctionAlreadyDefined(const std::string &funcName);
+    };
+    
+    using PixelShaderMainFunc = std::function<void()>;
+    
+    /*
+     * Using the same PixelShader instance in multiple threads to define data is not thread safe.
+     * All get*** functions are thread safe.
+     */
+    class PixelShader
+    {
+    public:
+        PixelShader();
+        
+        const std::string& getOutputAttributeName(i32 attributeIndex);
+        ShaderOutputVec4 defineOutputVec4(const std::string &name);
+        void defineMain(PixelShaderMainFunc mainFunc);
+        void assign(const ShaderOutputVec4 &lhsVariable, const ShaderVec4 &rhsVariable);
+        std::string build();
+    private:
+        void writeHeader(const std::string &code);
+        void writeBody(const std::string &code);
+        
+        /*
+         * Throws PixelShaderTooManyAttributes if too many pixel attributes are defined for the platform.
+         * Throws PixelShaderAttributeAlreadyDefined if a pixel attribute with the same name has already been defined.
+         */
+        i32 defineOutputVariable(const std::string &variableName, const char *typeName);
+    private:
+        std::string header;
+        std::string body;
+        int locationCounter;
+        i32 maxPixelAttribs; // Could make this static
+        std::unordered_map<std::string, i32> pixelAttributes;
+        std::vector<std::string> pixelAttributeNames;
+        bool mainFuncDefined;
+    };
+}