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Question linear tonemapping

Discussion in 'High Definition Render Pipeline' started by mlab2, Oct 5, 2023.

  1. mlab2

    mlab2

    Joined:
    May 21, 2022
    Posts:
    5
    I'm using the HDRP in a research application (Unity 2022.3.6, HDRP 14.0.8, though that's flexible), and I'd like to configure tonemapping so that when I double all light intensities, the RGB triplet for each pixel doubles. And when I double a surface albedo, the RGB triplet doubles. And so on. So the idea is that I want to configure tonemapping so that it doesn't create a nonlinear relationship between scene properties like light intensity, albedo, etc., and the final RGB triplets. I know how to do this in the BRP, but haven't figured it out yet in the HDRP.

    I tried adding a tonemapping override to the global volume and setting it to None. But when I check screen captures under a series of lighting intensities, the pixel intensities aren't proportional to light intensity. That's also true with the other tonemapping override settings (Neutral, ACES, etc.).

    I also added an exposure override and set that to Fixed, so I don't think that's the problem.

    I'm not sure if the problem is that I'm not using tonemapping right, or if there are other post-processing features (color adjustments? color curves?) that I should be configuring as well.

    Also, I understand that the point of tonemapping is to squeeze rendered HDR into displayable LDR, and that that usually requires compression -- for my application I'm fine with disabling that.

    Any suggestions appreciated.