HDR image effects

Unity Engine
1

Hi

I want to know how eye adaption images effect can find screen is dark and how can find screen is bright?
And is it possible to implement eye adaption on mobile targets? (with simply control brightness of a white texture)

2
  1. Quite simple - most eye adaptation effects do a gradual downsample of the screen until they get a 1-pixel sized “average” colour of the screen, then to get the brightness, you do essentially a weighted average of each channel in the pixel (because the human eye perceives red, green, and blue differently in terms of brightness).
    As an example in hlsl;
float GetLuminance(float3 color) {
  return dot(color, float3(0.299, 0.587, 0.114));
}

Uses fairly standard values (taken from TV brightness values) for the conversion.

  1. Definitely - PRISM’s eye adaptation (a PostFX stack I develop) works on mobile, but generally speaking, eye adaptation is used in HDR scenes, which aren’t common on mobile.
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