left over printf

seems to be unused

I think I would prefer if it was inside the Film structure instead. Avoiding fragmentation. Leaving this Cryptomatte struct for object data.

Make the Cryptomatte a friend of the Film class. But maybe better to merge the sorting to the Film struct.

Another idea, is to use GPU_R32F with multiple layer to avoid the unnecessary 4th comp.

Codestyle: use cryptomatte_ prefix for all functions in this file.

I would avoid the define that can polute other file. Either use const uint uint_max = 4294967295u (always use lower case suffix), or here, you can simply replace by 0xFFFFFFFFu. This is widely done in other places and I think it is acceptable.

This is the issue! dst refers to what is stored in the film. But incoming hash is src. Use FilmSample src = film_sample_get(0, texel_film); to get the center sample (location and weight). You can try using a constant weight for now.

Add comment that this is for animated / non static viewport. And that you clear the buffer.

IMO, we should avoid clearing every frame.

is that for testing? can't we choose what layer we want to visualize in viewport?

Comment style. use /**/

???

Use divide_ceil_i to show the intent. I would rename cryptomatte_levels to cryptomatte_samples_per_layer.

I would merge this with the film info file. No need for many different files concerning infos.

merge into one (keep eevee_cryptomatte_out). even if this causes more unused binds for the world.

Will use a different way to store the data. This isn't how it is actually used anymore.

Yes, was already thinking of doing that. The current code separation is not clean.

Y

That would become 3 store operations when drawing materials and 3 read operations during film accumulation. Haven't tested what the performance implications are think they should be negligible on modern hardware, but still...

DisplayMode is incorrect name; it is not only used for display, also for readback of render layers. Basically there are 3 places where the results can be read from, value array, half color array, or cryptomatte (full color). ePassStorageType?

Will add a note, that in the viewport only one layer is active and that only the first sample of that layer is shown to the user.

This is not a correct GLSL array declaration.