Adds a new kDirectionLight_ShadowFlag which indicates that lightPosition
is a vector pointing towards the light, and lightRadius is the blur
radius when the occluder is at z == 1. For other values of z it will
scale linearly. The direction is specified in device space.
Bug: skia:10781
Change-Id: I14d530f006e5541ed6e22bfbeb29c7441c21fb8e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/321792
Commit-Queue: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
63f0354b6d