Question How to obtain HD Camera's render average color?

I would like to obtain the average color of my main camera render in order to, among other things, dim the user interface in dark areas and vice versa for light area.

I thought of using Texture2D.GetPixel to get three pixels (or more with a precision setting) on screen and then average these over multiple frames, but in order to do that I'd need the render texture of the camera.

1. Is there way to get a render texture from the HD Camera without rendering again on a render texture via camera.target?
2. Is GetPixel the right method for the job?

 

Hi, I'm not an expert on this but I know that there might be a better way to do this in HDRP.

There's a special render texture called Color Pyramid in HDRP.

It does not include transparent objects but I suppose you are not looking for a 100% accurate average color?


You can access the highest mipmap level of Color Pyramid to get the average scene color.
(Unity-Documentation-Mipmaps)

You can, but I think a better way is to use compute shader.

• Compute shaders can easily access global render textures (Color Pyramid).
• Can use something like AsyncGPUReadback (or even don't need if outputting one value from compute shader).

 

You can still sample other mipmap levels of Color Pyramid (with different UV, which is a 2D screen coordinate) in a compute shader.

I think it should be more average than reading several pixels.

 

Thanks for the very valuable answer Will check this out, never played around with AsyncGPUReadback.