#include "ShaderProgram.h"

namespace charcoal
{
	ShaderProgram::ShaderProgram()
		: m_program(glCreateProgram())
	{}

	ShaderProgram::~ShaderProgram()
	{
		glDeleteProgram(m_program);
	}

	void ShaderProgram::attach_shader(const Shader& shader)
	{
		glAttachShader(m_program, shader.get_shader());
	}

	void ShaderProgram::link()
	{
		glLinkProgram(m_program);
		
		GLint program_linked;
		glGetProgramiv(m_program, GL_LINK_STATUS, &program_linked);
		if (program_linked != GL_TRUE)
		{
			GLsizei log_length = 0;
			GLchar message[1024];
			glGetProgramInfoLog(m_program, 1023, &log_length, message);
			message[log_length] = '\0'; // Add null terminator
			OutputDebugString("Error Linking Shader Program:\n");
			OutputDebugString(message);
			OutputDebugString("\n");
			throw EXCEPTION("Error linking Shader Program.");
		}

	}

	void ShaderProgram::use() const
	{
		glUseProgram(m_program);
	}

	GLuint ShaderProgram::get_program() const
	{
		return m_program;
	}
}