/******************************************************************************
Class:Shader
Implements:
Author:Rich Davison	<richard.davison4@newcastle.ac.uk>
Description:VERY simple class to encapsulate GLSL shader loading, linking,
and binding. Useful additions to this class would be overloaded functions to
replace the glUniformxx functions in external code, and possibly a map to store
uniform names and their resulting bindings. 

-_-_-_-_-_-_-_,------,   
_-_-_-_-_-_-_-|   /\_/\   NYANYANYAN
-_-_-_-_-_-_-~|__( ^ .^) /
_-_-_-_-_-_-_-""  ""   

*//////////////////////////////////////////////////////////////////////////////

#pragma once


#include <string>
#include <iostream>
#include <fstream>

#include "GL/glew.h"


enum ShaderStage {
	SHADER_VERTEX = 0,
	SHADER_FRAGMENT,
	SHADER_GEOMETRY,
	SHADER_TCS,
	SHADER_TES,
	SHADER_MAX
};

using namespace std;
class Shader	{
public:
	Shader(string vertex, string fragment , string geometry = "", string tcs = "", string tes = "" );
	~Shader(void);

	GLuint  GetShaderProgram() const { return program;}

	bool	ShaderLinked() const	 { return linkSuccess; }
	bool	LinkProgram();

	bool UsingDefaultShader() const {
		return usingBackupShader;
	}

protected:
	bool	LoadShaderFile(string from, string &into);
	GLuint	GenerateShader(string from, GLenum type);
	void	SetDefaultAttributes();

	void	LoadDefaultShader();

	GLuint objects[SHADER_MAX];
	GLuint program;

	bool loadSuccess;
	bool linkSuccess;
	bool usingBackupShader;
};