The previous algorithm was not using all of the requested grids to build a mesh
around the volume due to limitations regarding the use of a dense buffer to
gather information about the volume's topology. This resulted in artefacts during
rendering.
The mesh generation is now done by merging all of the input grids and using the
resulting grid's topology to create the mesh. The generation of the mesh
is still done in index space as before, and the vertices are converted to object
space by using the merged topology grid indexToWorld transform.
To be able to merge the grids together we have to make sure that their transformation
matrices and their index spaces match, thus, if they do not match we simply resample
the grids. This behaviour should tackle one other limitation of the current algorithm,
which is that only one transformation matrix was used to generate the final mesh.
If we do not have an OpenVDB grid for the requested volume data, we generate
a temporary OpenVDB grid for it.
Differential Revision: https://developer.blender.org/D8401
Optimization was disabled in this function to work around a bug in MSVC, use
a different solution that does not come with such a big performance regression.
The decomposed transform would have consists of nan values if the input
transform had zero scale.
Now the decomposition will check for zero scale, and if it is detected
then the result will be ensured to be finite. Additionally, rotation
value will be copied from previous/next time step to help avoiding
obscure interpolation.
The latter step can become more comprehensive than the current simple
implementation.
Differential Revision: https://developer.blender.org/D8450
I'm not sure if the Sky was deliberately left out or was just waiting for a
better moment, but so many I was disappointed that Sky in EEVEE is
completely white.
There are already 2 implementations (osl and gpu) so this is the third one.
Looking at other cases it seems that we are not supposed to share sources
between cycles and the rest? So the new util_sky_model files are just
copies of what is already in cycles, except that the data file uses the RGB
variant of the Hosek/Wilkie model, because we output RGB anyway (but can be
easily changed to XYZ if desired - the results are nearly identical).
I am not sure if it is okay to pass 3*9 float values as 3 mat4 uniforms (I
wanted to use mat3 but it does not work).
Also, should I cache the sky model data between renders if the parameters
do not change?
Reviewed By: fclem, brecht
Differential Revision: https://developer.blender.org/D7108
The problem here was numerical precision: The code calculates the angle between
sun and view direction, and the usual acos(dot(a, b)) approach for that has
poor numerical performance for almost parallel angles.
As a result, the generally tiny difference between floating point computation
between CPU and GPU was enough to make the sun vanish at different radii,
causing different results.
The new version fixes the difference by making the computation much more robust
on both platforms.
This patch adds support for the curve primitive from OptiX to Cycles. It's currently hidden
behind a debug option, since there can be some slight rendering differences still (because no
backface culling is performed and something seems off with endcaps). The curve primitive
was added with the OptiX 7.1 SDK and requires a r450 driver or newer, so this also updates
the codebase to be able to build with the new SDK.
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D8223
First benefit is reduced boilerplate code.
Second benefit is fixed warnings about using deprecated spin lock
on macOS when using SDK 10.12 and above.
Differential Revision: https://developer.blender.org/D8182
When we switched to MSVC2019 and C++17 we seemingly
managed to trigger a code-gen bug with MSVC in the
AVX code-path.
This change works around the issue by (hopefully
temporary) disabling the optimizer for the fast_exp2f4
function, given it is only used in a single pass
of the denoiser and nowhere else, this is luckily
not as bad as it could have been.
Once the compiler is fixed or a different fix is
available we'll have to revisit this.
Details and link to the repro posted to MS is
available in T78047
Compared to Optix denoise, this is usually slower since there is no GPU
acceleration. Some optimizations may still be possible, in avoid copies
to the GPU and/or denoising less often.
The main thing is that this adds viewport denoising support for computers
without an NVIDIA GPU (as long as the CPU supports SSE 4.1, which is nearly
all of them).
Ref T76259
No significant performance improvement is expected, but it means we have a
single thread pool throughout Blender. And it should make adding more
parallellization in the future easier.
After previous refactoring commits this is basically a drop-in replacement.
One difference is that the task pool had a mechanism for scheduling tasks to
the front of the queue to minimize memory usage. TBB has a smarter algorithm
to balance depth-first and breadth-first scheduling of tasks and we assume that
removes the need to manually provide hints to the scheduler.
Fixes T77533
This commit adds a new model to the Sky Texture node, which is based on a
method by Nishita et al. and works by basically simulating volumetric
scattering in the atmosphere.
By making some approximations (such as only considering single scattering),
we get a fairly simple and fast simulation code that takes into account
Rayleigh and Mie scattering as well as Ozone absorption.
This code is used to precompute a 512x128 texture which is then looked up
during render time, and is fast enough to allow real-time tweaking in the
viewport.
Due to the nature of the simulation, it exposes several parameters that
allow for lots of flexibility in choosing the look and matching real-world
conditions (such as Air/Dust/Ozone density and altitude).
Additionally, the same volumetric approach can be used to compute absorption
of the direct sunlight, so the model also supports adding direct sunlight.
This makes it significantly easier to set up Sun+Sky illumination where
the direction, intensity and color of the sun actually matches the sky.
In order to support properly sampling the direct sun component, the commit
also adds logic for sampling a specific area to the kernel light sampling
code. This is combined with portal and background map sampling using MIS.
This sampling logic works for the common case of having one Sky texture
going into the Background shader, but if a custom input to the Vector
node is used or if there are multiple Sky textures, it falls back to using
only background map sampling (while automatically setting the resolution to
4096x2048 if auto resolution is used).
More infos and preview can be found here:
https://docs.google.com/document/d/1gQta0ygFWXTrl5Pmvl_nZRgUw0mWg0FJeRuNKS36m08/view
Underlying model, implementation and documentation by Marco (@nacioss).
Improvements, cleanup and sun sampling by @lukasstockner.
Differential Revision: https://developer.blender.org/D7896
This patch will add some compiler hints to break unrolling in the
nestled for loops of the voronoi node.
Reviewed by: Brecht van Lommel
Differential Revision: https://developer.blender.org/D7574
This patch adds an AVX implementation of Perlin noise in Cycles.
An avxi type was also added as a utility based on the respective
type in Intel Embree.
Only 3D and 4D noise were implemented, there is no benefit for
utilizing AVX in 1D and 2D noise. The SSE trilinear interpolation
function was used in the AVX implementation because there is no
benefit from using AVX in interpolating the last three dimensions.
Differential Revision: https://developer.blender.org/D6680
The numbers here can probably be tweaked to be better, but it's hard to
predict and this should at least avoid excessive memory swapping.
Fixes T57064.
