Raindrops are now illuminated by distant light flares
* https://files.facepunch.com/jarryd-campi/2026/November/Unity_wKkR1wBhvT.mp4
Picks the 16 flares closest to the center of the screen to pass to the shader
Has some issues, there's no simple way to handle the flares being occluded by other geometry, we could maybe get away with it?