UltimateZoneBuilder/Source/Native/Shader.cpp

#include "Precomp.h"
#include "Shader.h"
#include "VertexDeclaration.h"
#include "RenderDevice.h"
#include <stdexcept>

void Shader::ReleaseResources()
{
	if (mProgram)
		glDeleteProgram(mProgram);
	if (mVertexShader)
		glDeleteShader(mVertexShader);
	if (mFragmentShader)
		glDeleteShader(mFragmentShader);
	mProgram = 0;
	mVertexShader = 0;
	mFragmentShader = 0;
}

bool Shader::Compile(const std::string& vertexShader, const std::string& fragmentShader)
{
	mVertexShader = CompileShader(vertexShader, GL_VERTEX_SHADER);
	if (!mVertexShader)
		return false;

	mFragmentShader = CompileShader(fragmentShader, GL_FRAGMENT_SHADER);
	if (!mFragmentShader)
		return false;

	mProgram = glCreateProgram();
	glAttachShader(mProgram, mVertexShader);
	glAttachShader(mProgram, mFragmentShader);
	glBindAttribLocation(mProgram, (GLuint)DeclarationUsage::Position, "AttrPosition");
	glBindAttribLocation(mProgram, (GLuint)DeclarationUsage::Color, "AttrColor");
	glBindAttribLocation(mProgram, (GLuint)DeclarationUsage::TextureCoordinate, "AttrUV");
	glBindAttribLocation(mProgram, (GLuint)DeclarationUsage::Normal, "AttrNormal");
	glLinkProgram(mProgram);

	GLint status = 0;
	glGetProgramiv(mProgram, GL_LINK_STATUS, &status);
	if (status != GL_TRUE)
	{
		GLsizei length = 0;
		glGetProgramiv(mProgram, GL_INFO_LOG_LENGTH, &length);
		std::vector<GLchar> errors(length + (size_t)1);
		glGetProgramInfoLog(mProgram, (GLsizei)errors.size(), &length, errors.data());
		mErrors = { errors.begin(), errors.begin() + length };

		glDeleteProgram(mProgram);
		glDeleteShader(mVertexShader);
		glDeleteShader(mFragmentShader);
		mProgram = 0;
		mVertexShader = 0;
		mFragmentShader = 0;
		return false;
	}

	TransformLocations[(int)TransformState::World] = glGetUniformLocation(mProgram, "World");
	TransformLocations[(int)TransformState::View] = glGetUniformLocation(mProgram, "View");
	TransformLocations[(int)TransformState::Projection] = glGetUniformLocation(mProgram, "Projection");

	return mProgram;
}

GLuint Shader::CompileShader(const std::string& code, GLenum type)
{
	GLuint shader = glCreateShader(type);
	const GLchar* sources[] = { (GLchar*)code.data() };
	const GLint lengths[] = { (GLint)code.size() };
	glShaderSource(shader, 1, sources, lengths);
	glCompileShader(shader);

	GLint status = 0;
	glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
	if (status != GL_TRUE)
	{
		GLsizei length = 0;
		glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &length);
		std::vector<GLchar> errors(length + (size_t)1);
		glGetShaderInfoLog(shader, (GLsizei)errors.size(), &length, errors.data());
		mErrors = { errors.begin(), errors.begin() + length };
		glDeleteShader(shader);
		return 0;
	}
	return shader;
}