Source: Renderables/SpriteRenderable.js

  1. /*
  2.  * File: SpriteRenderable.js
  3.  *  
  4.  * Texture objects where texture coordinate can change
  5.  */
  6. /*jslint node: true, vars: true */
  7. /*global gEngine: false, Renderable: false, TextureRenderable: false */
  8. /* find out more about jslint: http://www.jslint.com/help.html */
  10. // Constructor and object definition
  11. "use strict";  // Operate in Strict mode such that variables must be declared before used!
  13. /**
  14.  * Constructor of SpriteRenderable object.
  15.  * @class SpriteRenderable
  16.  * @param {Texture} myTexture Texture to be associated by object.
  17.  * @returns {SpriteRenderable} Instance of this SpriteRenderable object
  18.  */
  19. function SpriteRenderable(myTexture) {
  20.     TextureRenderable.call(this, myTexture);
  21.     Renderable.prototype._setShader.call(this, gEngine.DefaultResources.getSpriteShader());
  22.     this.mTexLeft = 0.0;   // bounds of texture coordinate (0 is left, 1 is right)
  23.     this.mTexRight = 1.0;  // 
  24.     this.mTexTop = 1.0;    //   1 is top and 0 is bottom of image
  25.     this.mTexBottom = 0.0; // 
  27.     // 
  28.     this._setTexInfo();
  29. }
  30. gEngine.Core.inheritPrototype(SpriteRenderable, TextureRenderable);
  32. //<editor-fold desc="Public Methods">
  34. // Convention: eName is an enumerated data type
  35. /**
  36.  * the expected texture cooridnate array is an array of 8 floats where elements:<p>
  37.  * [0] [1]: is u/v coordinate of Top-Right<p>
  38.  * [2] [3]: is u/v coordinate of Top-Left<p>
  39.  * [4] [5]: is u/v coordinate of Bottom-Right<p>
  40.  * [6] [7]: is u/v coordinate of Bottom-Left
  41.  * @memberOf SpriteRenderable
  42.  * @type {float[]|enum}
  43.  */
  44. SpriteRenderable.eTexCoordArray = Object.freeze({
  45.     eLeft: 2,
  46.     eRight: 0,
  47.     eTop: 1,
  48.     eBottom: 5
  49. });
  51. //**-----------------------------------------
  52. // Public methods
  53. //**-----------------------------------------
  55. /**
  56.  * specify element region by texture coordinate (between 0 to 1)
  57.  * @memberOf SpriteRenderable
  58.  * @param {float} left - Sets the Left UV Coordinate.
  59.  * @param {float} right - Sets the Right UV Coordinate.
  60.  * @param {float} bottom - Sets the Bottom UV Coordinate.
  61.  * @param {float} top - Sets the Top UV Coordinate.
  62.  * @returns {void}
  63.  */
  64. SpriteRenderable.prototype.setElementUVCoordinate = function (left, right, bottom, top) {
  65.     this.mTexLeft = left;
  66.     this.mTexRight = right;
  67.     this.mTexBottom = bottom;
  68.     this.mTexTop = top;
  69.     this._setTexInfo();
  70. };
  72. /**
  73.  * specify element region by pixel positions (between 0 to image resolutions)
  74.  * @memberOf SpriteRenderable
  75.  * @param {float} left - Sets the Left pixel position.
  76.  * @param {float} right - Sets the Right pixel position.
  77.  * @param {float} bottom - Sets the Bottom pixel position.
  78.  * @param {float} top - Sets the Top pixel position.
  79.  * @returns {void}
  80.  */
  81. SpriteRenderable.prototype.setElementPixelPositions = function (left, right, bottom, top) {
  82.     var imageW = this.mTextureInfo.mWidth;
  83.     var imageH = this.mTextureInfo.mHeight;
  85.     this.mTexLeft = left / imageW;
  86.     this.mTexRight = right / imageW;
  87.     this.mTexBottom = bottom / imageH;
  88.     this.mTexTop = top / imageH;
  89.     this._setTexInfo();
  90. };
  92. /**
  93.  * Returns a UV Coordinate Array.
  94.  * @memberOf SpriteRenderable
  95.  * @returns {float[]} UV Voordinate Array
  96.  */
  97. SpriteRenderable.prototype.getElementUVCoordinateArray = function () {
  98.     return [
  99.         this.mTexRight,  this.mTexTop,          // x,y of top-right
  100.         this.mTexLeft,   this.mTexTop,
  101.         this.mTexRight,  this.mTexBottom,
  102.         this.mTexLeft,   this.mTexBottom
  103.     ];
  104. };
  106. /**
  107.  * Draws the SpriteRenderable to the screen in the aCamera viewport.
  108.  * @memberOf SpriteRenderable
  109.  * @param {Camera} aCamera - drawing Camera of the SpriteRenderable.
  110.  * @returns {void}
  111.  */
  112. SpriteRenderable.prototype.draw = function (aCamera) {
  113.     // set the current texture coordinate
  114.     // 
  115.     // activate the texture
  116.     this.mShader.setTextureCoordinate(this.getElementUVCoordinateArray());
  117.     TextureRenderable.prototype.draw.call(this, aCamera);
  118. };
  120. //--- end of Public Methods
  121. //
  122. //</editor-fold>