SSR problem about reflectivity

I wonder if reflectivity will still be used when blur is enabled?
If reflectivity is still used for reflection intensity calculation, is it to take reflectivity according to the corresponding pixels for mixed calculation when the reflection results are merged?


Reflectivity is used to know how reflective a pixel is (thus, the strength of the reflection for that pixel), and roughness is used in the blur pass to smooth things out (the higher the roughness, the larger the blur radius).

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What I mean is that when the blur is not enabled, the pixels are directly mixed and calculated according to the reflectivity to reflect the reflection intensity. After the reflection blur is turned on, the SSR calculation result is image blurred and then image merged with the scene. Will this image merge consider relectivity? After turning on the reflection blur, is it also considered that the reflection intensity of different pixels may be different?

The first pass of the algorithm, when blur is enabled, works as follows:

  • for pixels with reflectivity >= reflectivityThreshold, calculate the reflection color with ray marching
    • store in a texture this color + a blur radius in the alpha channel. The blur radius is calculated according to the roughness (a smaller radius for a smaller roughness).
  • for non-reflective pixels (reflectivity < reflectivityThreshold), store (0,0,0,0)

The second pass is the blur itself on the texture created in the first pass and creates a blur texture (BT), which does nothing if the color is (0,0,0,0) and otherwise blurs each pixel based on the blur radius.

The third pass merges the texture created in the second pass with the regular color texture (RCT) of the scene:

  • for non-reflective pixels (reflectivity < reflectivityThreshold), it simply copies the color from the RCT
  • for reflective pixels, it blends the BT color with the RCT color based on the pixel reflectivity (+ SSR parameters strength and reflectionSpecularFalloffExponent).

I hope that clears things up.