EDF 4.1: Improved reflections patch

[metoxys]

EDF 4.1's reflections are completely and utterly awful. This changes the situation a lot.

Vanilla reflections have no fresnel, no angular falloff, and worst of all, 1024x1024 environment maps without LODs (I kid you not, even EDF 2025 on the Xbox 360, with its 256x256 envmaps, had the decency to have 8 mipmaps)

This patch augments a compute shader (first reverse-engineered from disasm and then A/B tested to achieve pixel parity) by adding a 25-tap angle-dependent cubic blur with quadratic weighing. Head-on reflections remain sharp (but not "I can make out every individual pixel" sharp) while grazing angles now get strong, colored, and natural-looking environment reflections

(no anti-aliasing was used in this before/after)