Scenes with a lot of walls is a large performance hit on WebGL

[caewok]

May be unfixable, but a scene with a lot of walls (test case was 2586 walls) is a serious performance hit. May be ways to lessen this impact:

• Turn off Clockwise sweep as EV is not using it?
• Check how walls are culled
• Switch to rendering smaller triangles for the shadows instead of wasting pixels on lit areas
• Make use of attribute instances to avoid uploading the same wall data to the GPU repeatedly