We now continue transparent paths after diffuse/glossy/transmission/volume
bounces are exceeded. This avoids unexpected boundaries in volumes with
transparent boundaries. It is also required for MIS to work correctly with
transparent surfaces, as we also continue through these in shadow rays.
The main visible changes is that volumes will now be lit by the background
even at volume bounces 0, same as surfaces.
Fixes T53914 and T54103.
Goal is to reduce OpenCL kernel recompilations.
Currently viewport renders are still set to use 64 closures as this seems to
be faster and we don't want to cause a performance regression there. Needs
to be investigated.
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D2775
The algorithm averages normals from nearby surfaces. It uses the same
sampling strategy as BSSRDFs, casting rays along the normal and two
orthogonal axes, and combining the samples with MIS.
The main concern here is that we are introducing raytracing inside
shader evaluation, which could be quite bad for GPU performance and
stack memory usage. In practice it doesn't seem so bad though.
Note that using this feature can easily slow down renders 20%, and
that if you care about performance then it's better to use a bevel
modifier. Mainly this is useful for baking, and for cases where the
mesh topology makes it difficult for the bevel modifier to work well.
Differential Revision: https://developer.blender.org/D2803
With a Titan Xp, reduces path trace local memory from 1092MB to 840MB.
Benchmark performance was within 1% with both RX 480 and Titan Xp.
Original patch was implemented by Sergey.
Differential Revision: https://developer.blender.org/D2249
This is done by storing only a subset of PathRadiance, and by storing
direct light immediately in the main PathRadiance. Saves about 10% of
CUDA stack memory, and simplifies subsurface indirect ray code.
Similar to what we did for area lights previously, this should help
preserve stratification when using multiple BSDFs in theory. Improvements
are not easily noticeable in practice though, because the number of BSDFs
is usually low. Still nice to eliminate one sampling dimension.
This was needed when we accessed OSL closure memory after shader evaluation,
which could get overwritten by another shader evaluation. But all closures
are immediatley converted to ShaderClosure now, so no longer needed.
Also pass by value and don't write back now that it is just a hash for seeding
and no longer an LCG state. Together this makes CUDA a tiny bit faster in my
tests, but mainly simplifies code.
When using the Normal output of the Texture Coordinate node on Point and Spot lamps, the coordinates now depend on the rotation of the lamp.
On Area lamps, the Parametric output of the Geometry node now returns UV coordinates on the area lamp.
Credit for the Area lamp part goes to Stefan Werner (from D1995).
Using ones complement for detecting if transform has been applied was confusing
and led to several bugs. With this proper checks are made.
Also added a few transforms where they were missing, mostly affecting baking
and displacement when `P` is used in the shader (previously `P` was in the
wrong space for these shaders)
Also removed `TIME_INVALID` as this may have resulted in incorrect
transforms in some cases.
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D2192
All the changes are mainly giving explicit tips on inlining functions,
so they match how inlining worked with previous toolkit.
This make kernel compiled by CUDA 8 render in average with same speed
as previous kernels. Some scenes are somewhat faster, some of them are
somewhat slower. But slowdown is within 1% so far.
On a positive side it allows us to enable newer generation cards on
buildbots (so GTX 10x0 will be officially supported soon).
This commit adds a new distribution to the Glossy, Anisotropic and Glass BSDFs that implements the
multiple-scattering microfacet model described in the paper "Multiple-Scattering Microfacet BSDFs with the Smith Model".
Essentially, the improvement is that unlike classical GGX, which only models single scattering and assumes
the contribution of multiple bounces to be zero, this new model performs a random walk on the microsurface until
the ray leaves it again, which ensures perfect energy conservation.
In practise, this means that the "darkening problem" - GGX materials becoming darker with increasing
roughness - is solved in a physically correct and efficient way.
The downside of this model is that it has no (known) analytic expression for evalation. However, it can be
evaluated stochastically, and although the correct PDF isn't known either, the properties of MIS and the
balance heuristic guarantee an unbiased result at the cost of slightly higher noise.
Reviewers: dingto, #cycles, brecht
Reviewed By: dingto, #cycles, brecht
Subscribers: bliblubli, ace_dragon, gregzaal, brecht, harvester, dingto, marcog, swerner, jtheninja, Blendify, nutel
Differential Revision: https://developer.blender.org/D2002
* When Baking wasn't used we got an error.
* On top of Volume Nodes (NODES_FEATURE_VOLUME), we now also check if we need volume sampling code,
so we can disable that as well and save some further compilation time.
This re-enables the AA jittering, but with proper clamping so that u >= 0,
v >= 0 and u+v <= 1.
Differential Revision: https://developer.blender.org/D1254
Now pass_filter is modified to have exactly the flags for the light components
that need to be baked, based on the shader type. This simplifies the logic.
There is no function pointers in OpenCL specification. For as long
as we want to support this platform we should follow the specifications.
While the code is not totally optimal now, it should not be that huge
of performance issue on CPU since it does jump tables just nicely, so
it's not that much extra computation here.
The combined pass is built with the contributions the user finds fit.
It is useful for lightmap baking, as well as non-view dependent effects
baking.
The manual will be updated once we get closer to the 2.77 release.
Meanwhile the new page can be found here:
http://dalaifelinto.com/blender-manual/render/cycles/baking.html
Reviewers: sergey, brecht
Differential Revision: https://developer.blender.org/D1674
This commit changes the way how we pass bounce information to the Light
Path node. Instead of manualy copying the bounces into ShaderData, we now
directly pass PathState. This reduces the arguments that we need to pass
around and also makes it easier to extend the feature.
This commit also exposes the Transmission Bounce Depth to the Light Path
node. It works similar to the Transparent Depth Output: Replace a
Transmission lightpath after X bounces with another shader, e.g a Diffuse
one. This can be used to avoid black surfaces, due to low amount of max
bounces.
Reviewed by Sergey and Brecht, thanks for some hlp with this.
I tested compilation and usage on CPU (SVM and OSL), CUDA, OpenCL Split
and Mega kernel. Hopefully this covers all devices. :)
This makes it possible to move some parts of evaluation from host to the device
and hopefully reduce memory usage by avoid having full RGBA buffer on the host.
Reviewers: juicyfruit, lukasstockner97, brecht
Reviewed By: lukasstockner97, brecht
Differential Revision: https://developer.blender.org/D1702
There were multiple issues which are solved now:
- It was possible that ray wouldn't be bounced off the BSSRDF, for example
when PDF or shader eval is zero. In this case PathState might have been
left in pre-bounced state which would have been gave incorrect shading
results.
This is solved by having separate PathState for each of the hits.
- Path radiance summing wasn't happening correct as well, indirect rays
were using wrong path radiance in the case when there were more than
one hit recorded.
This is now using a bit trickier state machine which calculates path
radiance for just SSS (both direct and indirect) and then sums it back
to the final radiance.
- Previous commit wasn't totally correct either and was an induced bug
due to wrong path state left from the "un-happened" ray bounce.
There should be no special case happening here, BSSRDFs will be replaced
with diffuse ones due to PATH_RAY_DIFFUSE_ANCESTOR flag.
- Merged back codebases for "delayed" and "immediate" indirect SSS ray
tracing, hopefully making it easier to maintain the codebase.
Sure this changes brings memory usage back by about 4-5%, but overall
it's still about 2x memory reduction for the experimental kernel here.
Thanks Brecht for the review!
There are some issues to be solved with the recent optimization we did for
the indirect rays for the SSS. Those issues will take a bit of a time to
be fully solved still and we need to unlock Caminandes team now, so let's
revert some changes back.
CUDA will still use delayed indirect rays since it's an experimental
feature.
For the details about what's to be done still please refer to T46880.
This wasn't really a complete fix and only worked if there was a single scatter
event recorded only. Proper fix requires some more thoughts to make it correct
without memory use increase.
This reverts commit bf9e88bfbe.
Radiance sum and reset was happening in different order after 26f1c51.
This is a quick fix to unlock Caminandes team, perhaps we can avoid having
separate variable to detect when radiance is to be sum.
This gives much lower stack usage on GPU and reduces kernel memory size to
around 448MB on GTX560Ti (comparing to 652MB with previous commit and 946MB
with official release). There's also a barely measurable speedup of around
5%, but this is to be confirmed still.
At this stage we're using only ~3% for the experimental kernel and SSS
rendering seems to be faster by 40% and after some further testing we might
consider making SSS and CMJ official features and remove experimental
precompiled kernels.
The idea is to delay shooting indirect rays for the SSS sampling and
trace them after the main integration loop was finished.
This reduces GPU stack usage even further and brings it down to around
652MB (comparing to 722MB before the change and 946MB with previous
stable release).
This also solves the speed regression happened in the previous commit
and now simple SSS scene (SSS suzanne on the floor) renders in 0:50
(comparing to 1:16 with previous commit and 1:03 with official release).
