message: Fix gaussian blur kernel computation
  This improves significantly VSM shadows with blur,
  but will also improve SSR and the flare.
diff: @@ -990,8 +990,15 @@ FrameGraphId<FrameGraphTexture> PostProcessManager::gaussianBlurPass(FrameGraph&
  float x1 = float(i * 2);
  float k0 = std::exp(-alpha * x0 * x0);
  float k1 = std::exp(-alpha * x1 * x1);
  +
  + // k * textureLod(..., o) with bilinear sampling is equivalent to:
  + // k * (s[0] * (1 - o) + s[1] * o)
  + // solve:
  + // k0 = k * (1 - o)
  + // k1 = k * o
  +
  float k = k0 + k1;
  - float o = k0 / k;
  + float o = k1 / k;
  kernel[i].x = k;
  kernel[i].y = o;
  totalWeight += (k0 + k1) * 2.0f;
  