metal:depth-state

(metal:depth-state ctx &key writes compare)

An MTLDepthStencilState: how a pipeline uses the depth attachment. :writes nil is the glow pass -- it READS the depth the solid pass wrote, so a sprite behind the machine is hidden, but writes none of its own, so sprites do not occlude each other. :compare defaults to metal:+compare-less+. Part of the metal package, a Metal drawing surface written in rontolisp over objc and loaded on first use: macOS (java -jar, the rontolisp binary, or a compiled .class / .jar; never a .wasm), with a display. See the macOS GUI guide.

CL-USER> (defvar *depth* (metal:depth-state *ctx*))
CL-USER> (defvar *read-only* (metal:depth-state *ctx* :writes nil))