So I started a lantern script. This works by drawing a circle with polygons around the player. Great! Problem is, I want to introduce multiple lightsources. When polygons overlap each other, it inverses the overlapping polygons. This means I simply can't just add each lightsource. Here's a screencap that shows what's going on:

How can I fix this? I know it's going to involved a bit of math... and I'm not that great at it, so go easy on me, please!