scene:background

(scene:background v rgba)

The colour a frame starts from, as an (r g b a) list. scene:viewer's :background sets the first one. Part of the scene package, a 3-D viewer for geom solids written in rontolisp over metal and appkit and loaded on first use: macOS (java -jar, the rontolisp binary, or a compiled .class / .jar; never a .wasm), with a display. See the solid modeling guide.

CL-USER> (scene:background *v* '(0.0 0.0 0.0 1.0))
NIL