`kernel_path.h` and `kernel_path_branched.h` have a lot of conditional code and
it was kind of hard to tell what code belonged to which directive. Should be
easier to read now.
Basically, the problem here was that the transform that's used to bring texture coordinates
to world space is either fetched while setting up the shader (with Object Motion is enabled) or
fetched when needed (otherwise). That helps to save ShaderData memory on OpenCL when Object Motion isn't needed.
Now, if OM is enabled, the Lamp transform can just be stored inside the ShaderData as well. The original commit just assumed it is.
However, when it's not (on OpenCL by default, for example), there is no easy way to fetch it when needed, since the ShaderData doesn't
store the Lamp index.
So, for now the lamps just don't support local texture coordinates anymore when Object Motion is disabled.
To fix and support this properly, one of the following could be done:
- Just always pre-fetch the transform. Downside: Memory Usage increases when not using OM on OpenCL
- Add a variable to ShaderData that stores the Lamp ID to allow fetching it when needed
- Store the Lamp ID inside prim or object. Problem: Cycles currently checks these for whether an object was hit - these checks would need to be changed.
- Enable OM whenever a Texture Coordinate's Normal output is used. Downside: Might not actually be needed.
This allows to save a memory copy, which will be particularly useful for network rendering.
Reviewers: sergey, brecht, dingto, juicyfruit, maiself
Differential Revision: https://developer.blender.org/D2323
In scenes with many lights, some of them might have a very small contribution to some pixels, but the shadow rays are traced anyways.
To avoid that, this patch adds probabilistic termination to light samples - if the contribution before checking for shadowing is below a user-defined threshold, the sample will be discarded with probability (1 - (contribution / threshold)) and otherwise kept, but weighted more to remain unbiased.
This is the same approach that's also used in path termination based on length.
Note that the rendering remains unbiased with this option, it just adds a bit of noise - but if the setting is used moderately, the speedup gained easily outweighs the additional noise.
Reviewers: #cycles
Subscribers: sergey, brecht
Differential Revision: https://developer.blender.org/D2217
This option allows to create a smoother transition between Bricks and Mortar - 0 applies no smoothing, and 1 smooths across the whole mortar width.
Mainly useful for displacement textures.
The new default value for the smoothing option is 0.1 to give some smoothing that helps with antialiasing, but existing nodes are loaded with smoothing 0 to preserve compatibility.
Reviewers: sergey, dingto, juicyfruit, brecht
Reviewed By: brecht
Subscribers: Blendify, nutel
Differential Revision: https://developer.blender.org/D2230
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).
Basically don't use rcp() in areas which seems to be critical after
second look. Also disabled some multiplication operators, not sure
yet why they might be a problem.
Tomorrow will be setting up a full test with all cases which were
buggy in our farm to see if this fix is complete.
Several ideas here:
- Optimize calculation of near_{x,y,z} in a way that does not require
3 if() statements per update, which avoids negative effect of wrong
branch prediction.
- Optimization of direction clamping for BVH.
- Optimization of point/direction transform.
Brings ~1.5% speedup again depending on a scene (unfortunately, this
speedup can't be sum across all previous commits because speedup of
each of the changes varies from scene to scene, but it still seems to
be nice solid speedup of few percent on Linux and bigger speedup was
reported on Windows).
Once again ,thanks Maxym for inspiration!
Still TODO: We have multiple places where we need to calculate near
x,y,z indices in BVH, for now it's only done for main BVH traversal.
Will try to move this calculation to an utility function and see if
that can be easily re-used across all the BVH flavors.
Similar to the previous commit, avoid negative effect of bad branch prediction.
Gives measurable performance up to ~2% in tests here.
Once again, thanks to Maxym Dmytrychenko!
Similar to regular triangle intersection case. Gives about 3% speedup rendering
SSS object on my desktop,
Question: how to avoid such a code duplication in a nice way without speed loss?
Note that volume rendering is not supported yet, this is a step towards that.
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D2299
This commit basically vectorizes existing code using AVX2 instructions
(without modifying algorithm itself). This gives quite nice speedups:
BMW: -8%
Classroom: -5%
Cat: -5%
Koro: +1%
Barcelona: -8%
That's on Linux machine, reported performance improvement on Windows
goes up to 20%.
Not currently sure why Koro is somewhat slower because it mainly uses
curve intersection tests, could be a time noise? Or osmething with the
cache utilization perhaps? In any case speedup in other scenes makes
me thinking that current state is acceptable for initial implementation.
This is again inspired by Maxym Dmytrychenko.
Based on existing ssef data type and to my knowledge it's also what happens in
Embree nowadays.
Inspired by Maxym Dmytrychenko and required for the upcoming triangle
intersection commit.
Hopefully the copyright message is correct.
When ray hits curve segment with SSS shader it was possible to have
uninitialized hit_P variable used for sampling.
Seems that was a reason of our headache of difference between AVX2
and SSE4 render results here, so now we can revert all the nasty
ifdef-ed inline policies.
Mostly this is making inlining match CUDA 7.5 in a few performance critical
places. The end result is that performance is now better than before, possibly
due to less register spilling or other CUDA 8.0 compiler improvements.
On benchmarks scenes, there are 3% to 35% render time reductions. Stack memory
usage is reduced a little too.
Reviewed By: sergey
Differential Revision: https://developer.blender.org/D2269
This is also an important mathematical operation that can be folded
if it is known that one argument is a certain constant. For colors
the operation is provided as a Gamma node.
The SVM Gamma node needs a small fix to make it follow the 0 ^ 0 == 1
rule, same as the Power node, or the Gamma node itself in OSL mode.
Reviewers: #cycles
Differential Revision: https://developer.blender.org/D2263
Some of the files were wrongly attributing code to some other
organizations and in few places proper attribution was missing.
This is mainly either a copy-paste error (when new file was
created from an existing one and header wasn't updated) or due
to some refactor which split non-original-BF code with purely
BF code.
Should solve some confusion around.
The light sampling functions calculate light sampling PDF for the case that the light has been randomly selected out of all lights.
However, since BPT handles lamps and meshlights separately, this isn't the case. So, to avoid a wrong result, the code just included the 0.5 factor in the throughput.
In theory, however, the correction should be made to the sampling probability, which needs to be doubled. Now, for the regular calculation, that's no real difference since the throughput is divided by the pdf.
However, it does matter for the MIS calculation - it's unbiased both ways, but including the factor in the PDF instead of the throughput should give slightly better results.
Reviewers: sergey, brecht, dingto, juicyfruit
Differential Revision: https://developer.blender.org/D2258
Sergey Sharybin
Mai Lavelle
Lukas Stockner
Hristo Gueorguiev
Brecht Van Lommel
Alexander Gavrilov