how to convert this code to three.js Water.prototype.addDrop = function(x, y, radius, strength) {   var this_ = this;   this.textureB.drawTo(function() {     this_.textureA.bind();     this_.dropShader.uniforms({       center: [x, y],       radius: radius,       strength: strength     }).draw(this_.plane);   });   this.textureB.swapWith(this.textureA); };