asc_lens

ASCENSION's lens. Six passes at afterLighting, in the order light passes through a camera: the circle of confusion (asc_coc, order 300), the disc gather (asc_gather, 302), a composite back into the scene colour (305), the camera-velocity smear (asc_camblur, 310), its composite (313), and the copy that carries this frame's camera into the next frame's smear (asc_camsave, 316).

The visual result is a photographed frame rather than a rendered one: what sits at the focus distance is sharp and everything else falls off the way an aperture makes it, and a moving camera leaves the exposure's smear instead of a stack of instantaneous samples.

Both halves have an off switch on the parameter buffer (lens_params[3].x for defocus, [3].y for the shutter), so either can be A/B'd against the same frame without unloading anything.

Driven by preseed.asc.asc_shots, which owns asc_lens_params and creates the feature. The handle is RAII — asc_shots holds it for the life of the part.