Optimize specular AA.

[wzw9803]

In this commit, we optimized the anti-aliasing of specular. Instead of only filtering geometryNormal before, we added filtering for normalMap.

This is a small change. We plan to do another optimization in the future. We may add some parameters to the material to control the strength of anti-aliasing to meet the different needs of different scenarios.

And thanks again for the relevant information provided by @VanderSP!

Reference :
Tokuyoshi and Kaplanya, Stable Geometric Specular Antialiasing with Projected-Space NDF Filtering, 2021
Tokuyoshi and Kaplanyan, Improved Geometric Specular Antialiasing, 2019
Tokuyoshi, Error Reduction and Simplification for Shading Anti-Aliasing, 2017
Kaplanyan, Rendering Highly Specular Materials, 2016
Kaplanyan, NDFFiltering, 2016
Rock-Solid Shading, Dan Baker and Stephen Hill, 2012
Stephen Hill, Specular Showdown, 2011

[wzw9803]

I tested Oasis, Three, T3d - master, T3d - feat-specular-antiAliasing - SPECULAR_AA2, Babylon, PlayCanvas antialiasing with the same model. PlayCanvas uses TAA anti-aliasing. I think the effect is the best when the camera is still, so we take the effect of PlayCanvas as the standard and have the following conclusions:

1. Babylon anti-aliasing works best, but maybe a bit too much, some highlight details seem to be lost. (maybe caused by different lighting)
   

2. T3d - feat-specular-antiAliasing - SPECULAR_AA2 Anti-aliasing effect Second, the advantage is that the anti-aliasing strength is adjustable, you can choose between anti-aliasing and highlight details, and adjust it to the highest strength, which is closer to the Babylon effect.
   

3. Oasis is slightly better than Three because Oasis handles NormalMap.
   

4. Three.
   

5. T3d - master
   

Now we are still not sure which anti-aliasing method to use, so this branch is temporarily reserved, and more scenarios may be needed for testing.

Resources:
Test Model: dreadroamer