shadowDepthBias property
Clip-space depth bias subtracted from the receiver before the shadow
test. Defaults to 0: a constant clip-space bias is badly behaved in a
perspective shadow (tiny near the light, large far away, which detaches
the shadow from a caster's base), so the normal-offset bias below does
the work instead. Raise it only to fight grazing-angle self-shadow acne.
Implementation
double shadowDepthBias;