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


PIXI.StripShader = function()
{
    /**
    * @property {any} program - The WebGL program.
    */
    this.program = null;

    /**
     * @property {array} fragmentSrc - The fragment shader.
     */
    this.fragmentSrc = [
        'precision mediump float;',
        'varying vec2 vTextureCoord;',
        'varying float vColor;',
        'uniform float alpha;',
        'uniform sampler2D uSampler;',

        'void main(void) {',
        '   gl_FragColor = texture2D(uSampler, vec2(vTextureCoord.x, vTextureCoord.y));',
        '   gl_FragColor = gl_FragColor * alpha;',
        '}'
    ];

    /**
    * @property {array} fragmentSrc - The fragment shader.
    */
    this.vertexSrc = [
        'attribute vec2 aVertexPosition;',
        'attribute vec2 aTextureCoord;',
        'attribute float aColor;',
        'uniform mat3 translationMatrix;',
        'uniform vec2 projectionVector;',
        'varying vec2 vTextureCoord;',
        'uniform vec2 offsetVector;',
        'varying float 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);',
        '   vTextureCoord = aTextureCoord;',
        '   vColor = aColor;',
        '}'
    ];
};

/**
* Initialises the shader
* @method init
*
*/
PIXI.StripShader.prototype.init = function()
{

    var gl = PIXI.gl;

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

    // get and store the uniforms for the shader
    this.uSampler = gl.getUniformLocation(program, 'uSampler');
    this.projectionVector = gl.getUniformLocation(program, 'projectionVector');
    this.offsetVector = gl.getUniformLocation(program, 'offsetVector');
    this.colorAttribute = gl.getAttribLocation(program, 'aColor');
    //this.dimensions = gl.getUniformLocation(this.program, 'dimensions');

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

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

    this.program = program;
};