docs: function RenderTexture(width, height)
  {
      EventTarget.call( this );
  
      this.width = width || 100;
      this.height = height || 100;
  
      this.identityMatrix = mat3.create();
  
      this.frame = new Rectangle(0, 0, this.width, this.height);
  
      if(globals.gl)
      {
          this.initWebGL();
      }
      else
      {
          this.initCanvas();
      }
  }