Is this the expected behavior of pack and unpack ID?

[aVersionOfReality]

Pack/Unpack ID is not behaving the way I thought it would. I thought that whatever channels went in, would be the same when they come out. But it seems that the input Blue and Alpha influence the Red and Green, and nothing comes out of them in the main pass?

Is this a bug, or am I misunderstanding how this 8bit packing works?

unpack.id.issue-1.mp4

[pragma37]

No, this is not expected to work (note that there's not really an "Unpack ID" node).
Packing a color to an ID converts it to a 16bit value, so it can't store the full 32 bit color.

Malt/Malt/Pipelines/NPR_Pipeline/Shaders/NPR_Pipeline/NPR_Mesh.glsl

Line 192 in f46cc94

void pack_id(

The Id node values can be used to compare them to other values stored in the IN_ID texture, but can't be unpacked back to its original value.

EDIT: It will work if the B and A channels are set to 0, but I wouldn't rely on that, since this is an implementation detail that may change in the future.

[aVersionOfReality]

Ah, alright. But it does seem to work for a single float passed through R? Or might that change too?

[pragma37]

That's what I meant, if B and A channels are set to 0, the R and G channels can be unpacked back to their original values.
But don't rely on that since that could change too.