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#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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