showPointShadowDebug property
Paints the point shadow's penumbra estimate into the surface buffer, and shows that instead of the lit image.
Red: the penumbra width, against the widest allowed. Green: how far the blocker was, against the light's range. Blue: the search found nothing.
It exists because two explanations for a broken contact-hardening estimate were argued from the finished picture and both turned out wrong. The quantity that settles it never leaves the shader, and nothing displayed it — so the debugging was five runs of guessing where it should have been one run of looking.
Implementation
final bool showPointShadowDebug;