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#include "../../../include/RenderBackend/OpenGL/VertexShader.hpp"
#include "../../../include/RenderBackend/OpenGL/CommonShader.hpp"
#include "../../../include/RenderBackend/OpenGL/opengl.hpp"
using namespace std;
namespace amalgine
{
VertexShaderTooManyAttributes::VertexShaderTooManyAttributes(i32 maxVertexAttributes) :
runtime_error(string("Attempting to define more than ") + to_string(maxVertexAttributes) + " vertex attributes")
{
}
VertexShaderAttributeAlreadyDefined::VertexShaderAttributeAlreadyDefined(const std::string &attributeName) :
runtime_error(string("A vertex attribute with the name ") + attributeName + " has already been defined")
{
}
VertexShaderInvalidAttributeName::VertexShaderInvalidAttributeName(const std::string &attributeName) :
runtime_error(string("Vertex attribute name ") + attributeName + " is invalid")
{
}
VertexShaderFunctionAlreadyDefined::VertexShaderFunctionAlreadyDefined(const std::string &funcName) :
runtime_error(string("Vertex shader function already defined: ") + funcName)
{
}
VertexShader::VertexShader() : locationCounter(0), mainFuncDefined(false)
{
glGetIntegerv(GL_MAX_VERTEX_ATTRIBS, &maxVertexAttribs);
writeHeader("#version 330 core\n\n");
}
const string& VertexShader::getInputAttributeName(i32 attributeIndex)
{
assert(attributeIndex < vertexAttributeNames.size());
return vertexAttributeNames[attributeIndex];
}
ShaderInputVec2 VertexShader::defineInputVec2(const std::string &name)
{
i32 attributeIndex = defineInputVariable(name, "vec2");
return ShaderInputVec2(this, attributeIndex);
}
void VertexShader::defineMain(VertexShaderMainFunc mainFunc)
{
if(mainFuncDefined)
throw VertexShaderFunctionAlreadyDefined("main");
writeBody("void main() {\n");
ShaderVec4 glPosition = mainFunc();
mainFuncDefined = true;
writeBody("gl_Position = ");
writeBody(glPosition.getOutput());
writeBody(";\n}\n\n");
}
i32 VertexShader::defineInputVariable(const string &variableName, const char *typeName)
{
if(!isShaderVariableNameValid(variableName.c_str()))
throw VertexShaderInvalidAttributeName(variableName);
if(locationCounter + 1 > maxVertexAttribs)
throw VertexShaderTooManyAttributes(maxVertexAttribs);
if(vertexAttributes.find(variableName) != vertexAttributes.end())
throw VertexShaderAttributeAlreadyDefined(variableName);
i32 attributeIndex = locationCounter;
vertexAttributes[variableName] = locationCounter;
vertexAttributeNames.push_back(variableName);
writeHeader("layout(location = ");
writeHeader(to_string(locationCounter));
++locationCounter;
writeHeader(") in ");
writeHeader(typeName);
writeHeader(" ");
writeHeader(variableName);
writeHeader(";\n");
return attributeIndex;
}
string VertexShader::build() const
{
std::string result;
result.reserve(header.size() + 2 + body.size());
result += header;
result += "\n";
result += body;
return result;
}
void VertexShader::writeHeader(const string &code)
{
header += code;
}
void VertexShader::writeBody(const string &code)
{
body += code;
}
}
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