Specular Aliasing flicker

Morioh · October 21, 2022, 10:50pm

Hi,

i just bought the game and played for some days and came across this heavy specular aliasing issue in combination with the bloom settings being used in this game.

https://drive.google.com/file/d/1OOKFszbJo9MsO5uVT_qptAGyG8744oKB/view?usp=sharing

I’ve been struggling with this myself as a shader developer for Unity.
GSAA or Geometric Specular Anti-Aliasing can help with that, just keep in mind that derrivatives are not performance free to use so best is to only implement this where it needs to be like in shaders that are used in complex geometry, also glossy materials will look different or more rough so tweaking the Variance, Threshold and Smoothness/Roughness values is needed and perhaps giving the user the choice via global property to activate/deactivate it if the performance is going to take a severe hit from it.
https://google.github.io/filament/Materials.html#materialdefinitions/materialblock/anti-aliasing:specularantialiasing

github.com

google/filament/blob/main/shaders/src/shading_lit.fs#L40


    return a;
#else
    return 1.0;
#endif
}

void applyAlphaMask(inout vec4 baseColor) {}

#endif

#if defined(GEOMETRIC_SPECULAR_AA)
float normalFiltering(float perceptualRoughness, const vec3 worldNormal) {
    // Kaplanyan 2016, "Stable specular highlights"
    // Tokuyoshi 2017, "Error Reduction and Simplification for Shading Anti-Aliasing"
    // Tokuyoshi and Kaplanyan 2019, "Improved Geometric Specular Antialiasing"

    // This implementation is meant for deferred rendering in the original paper but
    // we use it in forward rendering as well (as discussed in Tokuyoshi and Kaplanyan
    // 2019). The main reason is that the forward version requires an expensive transform
    // of the half vector by the tangent frame for every light. This is therefore an
    // approximation but it works well enough for our needs and provides an improvement