Hello, I'm super new to pixijs and am trying to do a scratch off type game, using the code samples from https://pixijs.github.io/examples/#/demos/mask-render-texture.js and https://pixijs.github.io/examples/#/demos/batch.js   Wherein, there's a bunch of particles on screen, using the particle container, that you're meant to "scratch-off" within a given time limit....I've tapped into function pointerMove(event) { if (dragging) { brush.position.copy(event.d