proc.stage

Plays a graph, or any subject that runs Generators, on the preview stage: the strip below the scene, under the preview studio's camera and light. Nothing is added to the scene, and a session's dispose takes everything away. play(graphRef, opts?) is the session of one graph on one temporary Generator; open(spec, opts?) takes any other subject the caller makes (spec.make), drives (spec.driver) and reads through the Generators it runs (spec.members); attach is the session of a subject that stands already. waitPresented(session) waits for the first frame, and run(session, opts?) plays it through and answers what it cost and looked like.

Part of @builtin::systems.procgen.proc; required as @builtin::systems.procgen.proc.stage.