Operating system: Win10 64b
Graphics card: Geforce GTX 1060 3GB
Short description of error
I'm trying to use the composite to pack as much grayscale masks into a single image with a combine node to use in a game engine, this technique is widely used to save memory during the game execution.
I have no problem when packing images to RGB channels, but when I try to pack a fourth image using the alpha channel, the R, G and B channels are affected by artifacts caused by the alpha channel, this one (A channel) exports fine though.
Exact steps for others to reproduce the error
I drew this four simple textures and packed into a blend file:
When I pack the first three into an RGBA image, without using the A Channel, everything goes fine: (I'm using unreal engine to see each channel)
But when I try to pack a fourth image using the A channel, the other three get corrupted, the rendered image looks fine, but each channel viewed separately looks bad:
The attached file contains the four images and the compositor setup: