Texture.prototype.loadImage = function(url) {
var image = new Image();
var self = this;
image.onload = function() {
gl.bindTexture(gl.TEXTURE_2D, self.texture);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, image);
}
image.src = url;
}