FelixMcFelix/laughing-ironman

/* global WebGLShader */
/**
* @classdesc Abstraction of shader references to allow easy manipulation.
* @class Palette.Shader
* @description Initialise and compile a valid Source Object into a Shader.
* @param {WebGLRenderingContext} gl - The context the shader will belong to and be compiled by.
* @param {string} name - The name the shader object will be referred to by.
* @param {number} type - The class of the shader contained, either Palette.Shader.VS or Palette.Shader.FS.
* @param {string} source - The source code to compile the shader from.
* @param {WebGLRenderingContext} gl - The context the shaders of this program will belong to and be compiled by.
* @param {object} [attrs] - The array which contains attribute names and default values, as an array of 3-tuples.
* @author FelixMcFelix (Kyle S.)
*/
Palette.Shader = function(gl, name, type, source, attrs){
    /**
    * The shader's name.
    * @name Palette.Shader#name
    * @type String
    * @protected
    * @readonly
    */
    this.name = name;

    /**
    * The type of shader, either Palette.Shader.VS or Palette.Shader.FS for objects.
    * @name Palette.Shader#type
    * @type int
    * @protected
    * @readonly
    */
    this.type = type;

    /**
    * The shader's attached context.
    * @name Palette.Shader#context
    * @type WebGLRenderingContext
    * @protected
    * @readonly
    */
    this.context = gl;

    /**
    * The shader's attribute array.
    * @name Palette.Shader#attrs
    * @type Array[]
    * @protected
    * @readonly
    */
    this.attrs = attrs;

    /**
    * The reference to the compiled shader in the WebGLRenderingContext.
    * @name Palette.Shader#shader
    * @type WebGLShader
    * @protected
    * @readonly
    */
    this.shader = null;

    /**
    * Has the shader attempted compilation yet?
    * @name Palette.Shader#compiled
    * @type Boolean
    * @private
    * @readonly
    */
    this.compiled = false;

    this.bakeShader(source);
};

Palette.Shader.prototype = {
    /**
    * Compile shader code from a source string. Once compiled, you cannot recompile.
    * @method Palette.Shader#bakeShader
    * @protected
    * @param {string} source - The source code to compile and attach to this shader object.
    * @return {boolean} True if successful, false if unsuccessful.
    */
    bakeShader: function(source){
        if (this.compiled){return null;}

        this.compiled = true;

        switch(this.type){
            case Palette.Shader.VS:
                this.shader = this.context.createShader(this.context.VERTEX_SHADER);
                break;
            case Palette.Shader.FS:
                this.shader = this.context.createShader(this.context.FRAGMENT_SHADER);
                break;
            default:
                return false;
        }

        this.context.shaderSource(this.shader, source);
        this.context.compileShader(this.shader);
        if (!this.context.getShaderParameter(this.shader, this.context.COMPILE_STATUS)) {
            alert("An error occurred compiling the shaders: " + this.context.getShaderInfoLog(this.shader));
            return false;
        }

        return true;
    }
};

Palette.Shader.VS        = 0;
Palette.Shader.FS        = 1;
Palette.Shader.LIST        = 2;

Palette.Shader.prototype.constructor = Palette.Shader;