scene:ray

(scene:ray v x y)

The world-space eye ray through a point of the view: (origin direction), two 3-vectors, the direction a unit vector. X and Y are view coordinates in points -- AppKit's, so the origin is the bottom-left corner and +y is up. This is what a pixel honestly is in a 3-D viewer: a point on the screen names a LINE through the world, and which point of that line was meant is the program's question. scene:on-click answers the common case over it. 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:ray *v* 450.0 320.0)
(#(305.2 -412.7 690.0) #(-0.24 0.32 -0.55))