/**
 * @author Mat Groves http://matgroves.com/ @Doormat23
 */


PIXI.PrimitiveShader = function(gl)
{
    this.gl = gl;

    // the webGL program..
    this.program = null;

    this.fragmentSrc = [
        'precision mediump float;',
        'varying vec4 vColor;',

        'void main(void) {',
        '   gl_FragColor = vColor;',
        '}'
    ];

    this.vertexSrc  = [
        'attribute vec2 aVertexPosition;',
        'attribute vec4 aColor;',
        'uniform mat3 translationMatrix;',
        'uniform vec2 projectionVector;',
        'uniform vec2 offsetVector;',
        'uniform float alpha;',
        'uniform vec3 tint;',
        'varying vec4 vColor;',

        'void main(void) {',
        '   vec3 v = translationMatrix * vec3(aVertexPosition , 1.0);',
        '   v -= offsetVector.xyx;',
        '   gl_Position = vec4( v.x / projectionVector.x -1.0, v.y / -projectionVector.y + 1.0 , 0.0, 1.0);',
        '   vColor = aColor * vec4(tint * alpha, alpha);',
        '}'
    ];

    this.init();
};

PIXI.PrimitiveShader.prototype.init = function()
{

    var gl = this.gl;

    var program = PIXI.compileProgram(gl, this.vertexSrc, this.fragmentSrc);
    gl.useProgram(program);

    // get and store the uniforms for the shader
    this.projectionVector = gl.getUniformLocation(program, 'projectionVector');
    this.offsetVector = gl.getUniformLocation(program, 'offsetVector');
    this.tintColor = gl.getUniformLocation(program, 'tint');


    // get and store the attributes
    this.aVertexPosition = gl.getAttribLocation(program, 'aVertexPosition');
    this.colorAttribute = gl.getAttribLocation(program, 'aColor');

    this.translationMatrix = gl.getUniformLocation(program, 'translationMatrix');
    this.alpha = gl.getUniformLocation(program, 'alpha');

    this.program = program;
};