MTLStoreAction.dontCare
The GPU has permission to discard the rendered contents of the attachment at the end of the render pass, replacing them with arbitrary data.
Declaration
case dontCareMentioned in
Discussion
Use this option when you need the attachment’s contents during the render pass but not afterwards. Some GPUs may still store the contents back to the texture, but you can’t rely on that behavior. You need to assume that GPU discarded the texture’s contents.