blender/intern/cycles/kernel/geom
Brecht Van Lommel 7a92b8820b Cycles: remove hair minimum width support.
This never really worked as it was supposed to. The main goal of this is to
turn noise from sampling tiny hairs into multiple layers of transparency that
do not need to be sampled stochastically. However the implementation of this
worked by randomly discarding hair intersections in BVH traversal, which
defeats the purpose.

If it ever comes back, it's best implemented outside the kernel as a preprocess
that changes hair radius before BVH building. This would also make it work with
Embree, where it's not supported now. But it's not so clear anymore that with
many AA samples and GPU rendering this feature is as helpful as it once was for
CPU raytracers with few AA samples.

The benefit of removing this feature is improved hair ray tracing performance,
tested on NVIDIA Titan Xp:

bmw27: +0.37%
classroom: +0.26%
fishy_cat: -7.36%
koro: -12.98%
pabellon: -0.12%

Differential Revision: https://developer.blender.org/D4532
2019-04-24 14:39:47 +02:00
..
geom_attribute.h ClangFormat: apply to source, most of intern 2019-04-17 06:21:24 +02:00
geom_curve_intersect.h Cycles: remove hair minimum width support. 2019-04-24 14:39:47 +02:00
geom_curve.h ClangFormat: apply to source, most of intern 2019-04-17 06:21:24 +02:00
geom_motion_curve.h ClangFormat: apply to source, most of intern 2019-04-17 06:21:24 +02:00
geom_motion_triangle_intersect.h ClangFormat: apply to source, most of intern 2019-04-17 06:21:24 +02:00
geom_motion_triangle_shader.h ClangFormat: apply to source, most of intern 2019-04-17 06:21:24 +02:00
geom_motion_triangle.h ClangFormat: apply to source, most of intern 2019-04-17 06:21:24 +02:00
geom_object.h ClangFormat: apply to source, most of intern 2019-04-17 06:21:24 +02:00
geom_patch.h ClangFormat: apply to source, most of intern 2019-04-17 06:21:24 +02:00
geom_primitive.h ClangFormat: apply to source, most of intern 2019-04-17 06:21:24 +02:00
geom_subd_triangle.h ClangFormat: apply to source, most of intern 2019-04-17 06:21:24 +02:00
geom_triangle_intersect.h ClangFormat: apply to source, most of intern 2019-04-17 06:21:24 +02:00
geom_triangle.h ClangFormat: apply to source, most of intern 2019-04-17 06:21:24 +02:00
geom_volume.h ClangFormat: apply to source, most of intern 2019-04-17 06:21:24 +02:00
geom.h Cleanup: strip trailing space for cycles 2018-07-06 10:17:58 +02:00