Commit Graph

8 Commits

Author SHA1 Message Date
11310b554a Cycles: avoid some CUDA performance on scenes without deformation motion blur. 2014-04-26 14:29:52 +02:00
9ab259f55b Cycles: shadow function optimization for transparent shadows (CPU only).
Old algorithm:

Raytrace from one transparent surface to the next step by step. To minimize
overhead in cases where we don't need transparent shadows, we first trace a
regular shadow ray. We check if the hit primitive was potentially transparent,
and only in that case start marching. this gives extra ray cast for the cases
were we do want transparency.

New algorithm:

We trace a single ray. If it hits any opaque surface, or more than a given
number of transparent surfaces is hit, then we consider the geometry to be
entirely blocked. If not, all transparent surfaces will be recorded and we
will shade them one by one to determine how much light is blocked. This all
happens in one scene intersection function.

Recording all hits works well in some cases but may be slower in others. If
we have many semi-transparent hairs, one intersection may be faster because
you'd be reinteresecting the same hairs a lot with each step otherwise. If
however there is mostly binary transparency then we may be recording many
unnecessary intersections when one of the first surfaces blocks all light.

We found that this helps quite nicely in some scenes, on koro.blend this can
give a 50% reduction in render time, on the pabellon barcelona scene and a
forest scene with transparent leaves it was 30%. Some other files rendered
maybe 1% or 2% slower, but this seems a reasonable tradeoff.

Differential Revision: https://developer.blender.org/D473
2014-04-21 19:34:25 +02:00
Sv. Lockal
e7c2578576 Cycles: avoid 1.0f/(1.0f/x) divisions, which msvc (only) can't optimize.
This makes bmw scene in msvc 12 builds 6% faster.
It also gives a minor speedup for SSE hair in all compilers.
2014-04-03 22:08:53 +04:00
e8b1cfed0a Cycles code refactor: replace magic ~0 values in the code with defines. 2014-03-29 13:03:47 +01:00
6020d00990 Cycles: add support for mesh deformation motion blur. 2014-03-29 13:03:47 +01:00
0509553b5e Cycles code refactor: changes to make adding new primitive types easier. 2014-03-29 13:03:46 +01:00
41d1675053 Cycles code refactor: move more geometry code into per primitive files. 2014-03-29 13:03:45 +01:00
84470a1190 Cycles code refactor: move geometry related kernel files into own directory. 2014-03-29 13:03:45 +01:00