Banding with HDR setup?

Questions & Answers
1

What are the proper steps to render to a 32 bit buffer and process with a tonemapping shader?

This is what I'm doing:

    RenderTexture rtHDR = RenderTexture.GetTemporary (source.width, source.height , 0, RenderTextureFormat.ARGB32); 
    m_HDR_Material.SetTexture ("_HDR", rtHDR);
    Graphics.Blit (source, rtHDR);

    //_________FINAL OUTPUT TO SCREEN
    Graphics.Blit (rtHDR, destination,m_HDR_Material, 0); //TONEMAP SHADER
    RenderTexture.ReleaseTemporary (rtHDR);

I'm seeing banding in my HDR texture using this approach, which means it is not 32 bit; the banding is so severe, I doubt it's even 16 bit.

The HDR's are set to ARGB32 in the texture importer, and they are 32 bit EXR's.

Does anyone have any suggestion for me to try? I'm not sure what else to try.

2

As far as I know, ARGB32 refers to 32bit for all channels, meaning that it is just 8 bit per channel R, G, B or A. You would need more, 32bit hdr is actually 96bit for all three channels. As far as I know, unity3d doesn't support this right now?

Cheers

Robert

3

should be

RenderTextureFormat.ARGBFloat

to get 32 bit per channel

and probably also set

RenderTextureReadWrite.Linear;

for the temp RenderTex to skip gamma conversion