From ca92d8c90f7103db6d7cae4cef49b278d804b474 Mon Sep 17 00:00:00 2001
From: dec05eba <dec05eba@protonmail.com>
Date: Wed, 20 Dec 2017 20:55:05 +0100
Subject: Create shader using c++ code

---
 src/RenderBackend/OpenGL/PixelShader.cpp | 114 +++++++++++++++++++++++++++++++
 1 file changed, 114 insertions(+)
 create mode 100644 src/RenderBackend/OpenGL/PixelShader.cpp

(limited to 'src/RenderBackend/OpenGL/PixelShader.cpp')

diff --git a/src/RenderBackend/OpenGL/PixelShader.cpp b/src/RenderBackend/OpenGL/PixelShader.cpp
new file mode 100644
index 0000000..cbdc842
--- /dev/null
+++ b/src/RenderBackend/OpenGL/PixelShader.cpp
@@ -0,0 +1,114 @@
+#include "../../../include/RenderBackend/OpenGL/PixelShader.hpp"
+#include "../../../include/RenderBackend/OpenGL/CommonShader.hpp"
+#include "../../../include/RenderBackend/OpenGL/opengl.hpp"
+#include <cassert>
+
+using namespace std;
+
+namespace amalgine
+{
+    PixelShaderTooManyAttributes::PixelShaderTooManyAttributes(i32 maxPixelAttributes) : 
+        runtime_error(string("Attempting to define more than ") + to_string(maxPixelAttributes) + " pixel attributes")
+    {
+        
+    }
+    
+    PixelShaderAttributeAlreadyDefined::PixelShaderAttributeAlreadyDefined(const std::string &attributeName) : 
+        runtime_error(string("A pixel attribute with the name ") + attributeName + " has already been defined")
+    {
+        
+    }
+    
+    PixelShaderInvalidAttributeName::PixelShaderInvalidAttributeName(const std::string &attributeName) : 
+        runtime_error(string("Pixel attribute name ") + attributeName + " is invalid")
+    {
+        
+    }
+    
+    PixelShaderFunctionAlreadyDefined::PixelShaderFunctionAlreadyDefined(const std::string &funcName) : 
+        runtime_error(string("Pixel shader function already defined: ") + funcName)
+    {
+        
+    }
+    
+    PixelShader::PixelShader() : locationCounter(0), mainFuncDefined(false)
+    {
+        glGetIntegerv(GL_MAX_DRAW_BUFFERS, &maxPixelAttribs);
+        writeHeader("#version 330 core\n\n");
+    }
+    
+    const string& PixelShader::getOutputAttributeName(i32 attributeIndex)
+    {
+        assert(attributeIndex < pixelAttributeNames.size());
+        return pixelAttributeNames[attributeIndex];
+    }
+    
+    ShaderOutputVec4 PixelShader::defineOutputVec4(const std::string &name)
+    {
+        i32 attributeIndex = defineOutputVariable(name, "vec4");
+        return ShaderOutputVec4(this, attributeIndex);
+    }
+    
+    void PixelShader::defineMain(PixelShaderMainFunc mainFunc)
+    {
+        if(mainFuncDefined)
+            throw PixelShaderFunctionAlreadyDefined("main");
+        
+        writeBody("void main() {\n");
+        mainFunc();
+        mainFuncDefined = true;
+        writeBody("}\n\n");
+    }
+    
+    void PixelShader::assign(const ShaderOutputVec4 &lhsVariable, const ShaderVec4 &rhsVariable)
+    {
+        writeBody(lhsVariable.getName());
+        writeBody(" = ");
+        writeBody(rhsVariable.getOutput());
+        writeBody(";\n");
+    }
+    
+    i32 PixelShader::defineOutputVariable(const string &variableName, const char *typeName)
+    {
+        if(!isShaderVariableNameValid(variableName.c_str()))
+            throw PixelShaderInvalidAttributeName(variableName);
+        
+        if(locationCounter + 1 > maxPixelAttribs)
+            throw PixelShaderTooManyAttributes(maxPixelAttribs);
+        
+        if(pixelAttributes.find(variableName) != pixelAttributes.end())
+            throw PixelShaderAttributeAlreadyDefined(variableName);
+        
+        i32 attributeIndex = locationCounter;
+        pixelAttributes[variableName] = locationCounter;
+        pixelAttributeNames.push_back(variableName);
+        
+        ++locationCounter;
+        writeHeader("out ");
+        writeHeader(typeName);
+        writeHeader(" ");
+        writeHeader(variableName);
+        writeHeader(";\n");
+        return attributeIndex;
+    }
+    
+    string PixelShader::build()
+    {
+        std::string result;
+        result.reserve(header.size() + 2 + body.size());
+        result += header;
+        result += "\n";
+        result += body;
+        return result;
+    }
+    
+    void PixelShader::writeHeader(const string &code)
+    {
+        header += code;
+    }
+    
+    void PixelShader::writeBody(const string &code)
+    {
+        body += code;
+    }
+}
-- 
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