BSP World Overdraw Optimizations Progress (Patreon)

This map, sm198_mug.bsp from the Speedmapping pack 198, is great for stress testing BSP overdraw. In the first screenshot, you can see how it brings Retroquad's framerate to a crawl.

Now I've implemented an optimization in the parts of the BSP renderer dedicated to the BSP map (also known as "world" in the engine code). By disabling all entities and rendering the world alone, you can see the difference in performance:

The second screenshot shows the performance of this map in Retroquad 0.17.1.

The third screenshot shows its performance with the current code. An increase of 7 frames per second, which is up to 29% faster!

I still have some ideas to optimize the BSP world renderer further, but first I'm going to do some similar optimizations in the BSP entities renderer.