These don't really work as scene linear with sRGB transfer function for e.g.
ACEScg, there are not enough bits. If you want wide gamut you need to use
float colors.
Pull Request: https://projects.blender.org/blender/blender/pulls/145763
It has ~1.2x speed-up on CPU and ~1.5x speed-up on GPU (tested on Metal
M2 Ultra).
Individual samples are noisier, but equal time renders are mostly
better.
Note that volume emission renders differently than before.
Pull Request: https://projects.blender.org/blender/blender/pulls/144451
The distance sampling is mostly based on weighted delta tracking from
[Monte Carlo Methods for Volumetric Light Transport Simulation]
(http://iliyan.com/publications/VolumeSTAR/VolumeSTAR_EG2018.pdf).
The recursive Monte Carlo estimation of the Radiative Transfer Equation is
\[\langle L \rangle=\frac{\bar T(x\rightarrow y)}{\bar p(x\rightarrow
y)}(L_e+\sigma_s L_s + \sigma_n L).\]
where \(\bar T(x\rightarrow y) = e^{-\bar\sigma\Vert x-y\Vert}\) is the
majorant transmittance between points \(x\) and \(y\), \(p(x\rightarrow
y) = \bar\sigma e^{-\bar\sigma\Vert x-y\Vert}\) is the probability of
sampling point \(y\) from point \(x\) following exponential
distribution.
At each recursive step, we randomly pick one of the two events
proportional to their weights:
* If \(\xi < \frac{\sigma_s}{\sigma_s+\vert\sigma_n\vert}\), we sample
scatter event and evaluate \(L_s\).
* Otherwise, no real collision happens and we continue the recursive
process.
The emission \(L_e\) is evaluated at each step.
This also removes some unused volume settings from the UI:
* "Max Steps" is removed, because the step size is automatically specified
by the volume octree. There is a hard-coded threshold `VOLUME_MAX_STEPS`
to prevent numerical issues.
* "Homogeneous" is automatically detected during density evaluation
An option "Unbiased" is added to the UI. When enabled, densities above
the majorant are clamped.
Add new "Linear 3D Curves" option in the Curves panel in the render
properties. This renders curves as linear segments rather than smooth
curves, for faster render time at the cost of accuracy.
On NVIDIA Blackwell GPUs, this can give a 6x speedup compared to smooth
curves, due to hardware acceleration. On NVIDIA Ada there is still
a 3x speedup, and CPU and other GPU backends will also render this
faster.
A difference with smooth curves is that these have end caps, as this
was simpler to implement and they are usually helpful anyway.
In the future this functionality will also be used to properly support
the CURVE_TYPE_POLY on the new curves object.
Pull Request: https://projects.blender.org/blender/blender/pulls/139735
Stochastically turn a tricubic filter into a trilinear one. This
reduces the number of taps from 64 to 8. It combines ideas from
the "Stochastic Texture Filtering" paper and our previous GPU
sampling of 3D textures.
This is currently only used in a few places where we know stochastic
interpolation is valid or close enough in practice.
* Principled volume density, color and temperature
* Motion blur velocity
On an Macbook Pro M3 with the openvdb_smoke.blend regression test
and cubic sampling, this gives a ~2x speedup for CPU and ~4x speedup
for GPU. However it also increases noise, usually only a little. Equal
time renders for this scene show a clear reduction in noise for both
CPU and GPU.
Note we can probably get a bigger speedup with acceptable noise trade-off
using full stochastic sampling, but will investigate that separately.
Pull Request: https://projects.blender.org/blender/blender/pulls/132908
This allows users to implement arbitrary camera models using OSL by writing
shaders that take an image position as input and compute ray origin and
direction.
The obvious applications for this are e.g. panorama modes, lens distortion
models and realistic lens simulation, but the possibilities are endless.
Currently, this is only supported on devices with OSL support, so CPU and
OptiX. However, it is independent from the shading model used, so custom
cameras can be used without getting the performance hit of OSL shading.
A few samples are provided as Text Editor templates.
One notable current limitation (in addition to the limited device support)
is that inverse mapping is not supported, so Window texture coordinates and
the Vector pass will not work with custom cameras.
Pull Request: https://projects.blender.org/blender/blender/pulls/129495
In forward path tracing, when we pass volume bounding meshes, we
accumulate `volume_bounds_bounce`. We should match this behaviour in NEE
instead of accumulating `transparent_bounce`.
Pull Request: https://projects.blender.org/blender/blender/pulls/137556
This makes it possible to restore previous Blender 4.3 behavior of bump
mapping, where the large filter width was sometimes (ab)used to get a bevel
like effect on stepwise textures.
For bump from the displacement socket, filter width remains fixed at 0.1.
Ref #133991, #135841
Pull Request: https://projects.blender.org/blender/blender/pulls/136465
The code which was checking whether local intersection is to be
recorded, and under which index was duplicated for triangles,
motion triangles, and HIP-RT triangle filter function.
This change moves the common logic to an utility function which
is reused from all the places mentioned above.
Pull Request: https://projects.blender.org/blender/blender/pulls/136244
* Add SubdAttributeInterpolation class for linear attribute interpolation.
* Dicing computes ptex UV and face ID for interpolation.
* Simplify mesh storage of subd primitive counts
* Remove kernel code for subd attribute interpolation
* Remove patch table packing and upload
The old optimization adds a fair amount of complexity to the kernel, affecting
performance even when not using the feature. It's also not that useful as it
does not work for UVs that needs special interpolation. With this simpler code
it should be easier to make it feature complete.
Pull Request: https://projects.blender.org/blender/blender/pulls/135681
This is an intermediate steps towards making lights actual geometry.
Light is now a subclass of Geometry, which simplifies some code.
The geometry is not added to the BVH yet, which would be the next
step and improve light intersection performance with many lights.
This makes object attributes work on lights.
Co-authored-by: Lukas Stockner <lukas@lukasstockner.de>
Pull Request: https://projects.blender.org/blender/blender/pulls/134846
The attribute handling code in the kernel is currently highly duplicated since
it needs to handle five different data types and we couldn't use templates
back then.
We can now, so might as well make use of it and get rid of ~1000 lines.
There are also some small fixes for the GPU OSL code:
- Wrong derivative for .w component when converting float2/float3->float4
- Different conversion for float2->float (CPU averages, GPU used to take .x)
- Removed useless code for converting to float2, not used by OSL
Pull Request: https://projects.blender.org/blender/blender/pulls/134694
In Cycles lights can be given a light falloff node to control their
light falloff.
This worked by multiplying the light's strength by different
combinations of the ray length, which would be FLT_MAX for
distant lights. This resulting in almost every configuration of the
light falloff node overflowing when used on distant lights, which is
undesirable.
This commit fixes this issue by ignoring most of the functions of the
light falloff node when used on a distant light.
And in the process fixes a small discrepancy between SVM and OSL when
using the light falloff node on distant lights.
Pull Request: https://projects.blender.org/blender/blender/pulls/134539
The derivatives of the normal were simply not computed.
The offsetted normals are computed by perturbating the barycentric
coordinates. At triangle boundaries, the normals are extrapolated,
so discontinuities might be visible.
Currently only supported on triangles.
Pull Request: https://projects.blender.org/blender/blender/pulls/133769
- Rename dx/dy -> dfdx/dfdy to match the actual computed quantity
- Add template functions to compute dfdx/dfdy on triangles for sharing
among different data types
- Add documentation to some functions
- Some code shuffling that makes it easier to scale dfdx/dfdy in the
future
- Some other trivial changes
The issue here is that originally, the step count for the geometry's
motion and the object transform's motion were tied together, so a
single variable is used to store that step count.
However, when using the velocity attribute, it's possible for the step
counts to differ, which will lead to an incorrect interpolated object
transform in the kernel.
Pull Request: https://projects.blender.org/blender/blender/pulls/133788
Check was misc-const-correctness, combined with readability-isolate-declaration
as suggested by the docs.
Temporarily clang-format "QualifierAlignment: Left" was used to get consistency
with the prevailing order of keywords.
Pull Request: https://projects.blender.org/blender/blender/pulls/132361
* Use .empty() and .data()
* Use nullptr instead of 0
* No else after return
* Simple class member initialization
* Add override for virtual methods
* Include C++ instead of C headers
* Remove some unused includes
* Use default constructors
* Always use braces
* Consistent names in definition and declaration
* Change typedef to using
Pull Request: https://projects.blender.org/blender/blender/pulls/132361
Fixes missing intersections on straight 3D curves with the
Metal backend, with BVH2.
This issue could of manifested on other devices, but didn't seem to
in practice.
Pull Request: https://projects.blender.org/blender/blender/pulls/126197
I ran into this in a test scene - somehow the normalization here can result
in NaN (so presumably a zero vector). I don't think this has a notable
performance impact from some basic tests.
Pull Request: https://projects.blender.org/blender/blender/pulls/125930
Light linking was never working correctly in volume segment with light
tree, because `sd->object` was not assigned, thus
`light_link_receiver_nee(kg, sd)` always returned `OBJECT_NONE`, causing
the light tree sample to fail. This problem was revealed by fdc2962beb
since now the same light is used for volume segment and volume.
Also ensure we don't sample position on the light if sampling from
volume segment is failed, by setting `emitter_id` to `EMITTER_NONE` in
such cases.
Pull Request: https://projects.blender.org/blender/blender/pulls/122999
This PR fixes the (currently unused) scene-based selective feature compilation macros. These feature based macros haven't been used for a few years, and enabling them currently results in compilation errors.
The only functional change in this PR is in geom/primitive.h where undef-ing `__HAIR__` had exposed an inconsistency in how pointcloud attributes were being fetched. Using the more general `primitive_surface_attribute_float4` (instead of `curve_attribute_float4`) fixed a compilation error that occurred when rendering pointcloud unit test scenes with adaptive compilation enabled.
Pull Request: https://projects.blender.org/blender/blender/pulls/121216
Global built-ins appear to not work on AMD cards.
Also add a tweak to avoid a performance regression, similar
to what was done before. Disable adaptive subdivision kernel
code if not used.
Pull Request: https://projects.blender.org/blender/blender/pulls/119175
Along with the 4.1 libraries upgrade, we are bumping the clang-format
version from 8-12 to 17. This affects quite a few files.
If not already the case, you may consider pointing your IDE to the
clang-format binary bundled with the Blender precompiled libraries.
`sd->type` was set to `PRIMITIVE_TRIANGLE` when it should be
`PRIMITIVE_LAMP`.
Function #lights_intersect_impl sets `isect->prim` to `lamp`, which is
passed to function #shader_setup_from_sample. There `prim != PRIM_NONE`
is evaluated to `true`, thus setting `sd->type` to `PRIMITIVE_TRIANGLE`
erroneously. This fix checks `lamp != LAMP_NONE` first, as in all other
usages of #shader_setup_from_sample `LAMP_NONE` is passed as the value
of `lamp`.
Pull Request: https://projects.blender.org/blender/blender/pulls/108769
This is added so that some texture pipeline with point light and spot
light could work as before. Some people use the Normal socket from
Texture Coordinate node for texturing light, however the Normal there is
actually the incoming light direction and should be corrected. Using the
Parametric socket from Geometry node + normal transform from world to
object with Vector Transform node delivers the same result as using the
Normal socket from Texture Coordinate node.
Currently for lights only normal transformation works, because only
there we fetch light transform properly. This is a confusing behaviour,
but testing if it's a lamp in all relevant functions could have bad
impact on the performance. A more proper solution would be to change
lights to real objects, which is planned for the future.
Pull Request: https://projects.blender.org/blender/blender/pulls/108666
