We forgot to update this code as part of D3108. I'd like to include this in 2.90,
it's entirely broken now so can't really get any worse.
Differential Revision: https://developer.blender.org/D8738
The return value of scene_intersect must be checked, the isect struct members
can't be assumed to be initialized if that returns false.
Differential Revision: https://developer.blender.org/D8692
The fisheye camera setup causes the edges of the image to not shoot primary rays. This was not
respected by OptiX because of an optimization that tried to reduce conditionals around trace calls.
Removing that does not seem to have an impact on performance anymore however and it fixes
the issue.
The sky will appear brighter than before by default. To compensate for this,
lower exposure in the Film panel. The default altitude was also changed from
90 to 15 degrees.
Patch contributed by Marco with the help of Ryan Jones.
Differential Revision: https://developer.blender.org/D8285
This patch changes the discovery of pre-compiled kernels, to look for any PTX, even if
it does not match the current architecture version exactly. It works because the driver can
JIT-compile PTX generated for architectures less than or equal to the current one.
This e.g. makes it possible to render on a new GPU architecture even if no pre-compiled
binary kernel was distributed for it as part of the Blender installation.
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D8332
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
For GPU debugging purposes, it is still possible to render with the same BVH2
on the CPU using the Debug panel in the render properties.
Note that building Blender without Embree will now lead to significantly reduced
performance in CPU rendering, and a few of the Cycles regression tests will fail
due to small pixel differences.
Ref T73778
Depends on D8014
Maniphest Tasks: T73778
Differential Revision: https://developer.blender.org/D8015
Also removing the curve system manager which only stored a few curve intersection
settings. These are all changes towards making shape and subdivision settings
per-object instead of per-scene, but there is more work to do here.
Ref T73778
Depends on D8013
Maniphest Tasks: T73778
Differential Revision: https://developer.blender.org/D8014
This keeps render results compatible for combined CPU + GPU rendering.
Peformance and quality primitives is quite different than before. There
are now two options:
* Rounded Ribbon: render hair as flat ribbon with (fake) rounded normals, for
fast rendering. Hair curves are subdivided with a fixed number of user
specified subdivisions.
This gives relatively good results, especially when used with the Principled
Hair BSDF and hair viewed from a typical distance. There are artifacts when
viewed closed up, though this was also the case with all previous primitives
(but different ones).
* 3D Curve: render hair as 3D curve, for accurate results when viewing hair
close up. This automatically subdivides the curve until it is smooth.
This gives higher quality than any of the previous primitives, but does come
at a performance cost and is somewhat slower than our previous Thick curves.
The main problem here is performance. For CPU and OpenCL rendering performance
seems usually quite close or better for similar quality results.
However for CUDA and Optix, performance of 3D curve intersection is problematic,
with e.g. 1.45x longer render time in Koro (though there is no equivalent quality
and rounded ribbons seem fine for that scene). Any help or ideas to optimize this
are welcome.
Ref T73778
Depends on D8012
Maniphest Tasks: T73778
Differential Revision: https://developer.blender.org/D8013
The kernel did not work correctly when these were disabled anyway. The
optimized BVH traversal for the no instances case was also only used on
the CPU, so no longer makes sense to keep.
Ref T73778
Depends on D8010
Maniphest Tasks: T73778
Differential Revision: https://developer.blender.org/D8011
The hair BSDFs are already designed to assume this, and disabling backface
culling would break them in some cases.
Ref T73778
Depends on D8009
Maniphest Tasks: T73778
Differential Revision: https://developer.blender.org/D8010
Triangles were very memory intensive. The only reason they were not removed yet
is that they gave more accurate results, but there will be an accurate 3D curve
primitive added for this.
Line rendering was always poor quality since the ends do not match up. To keep CPU
and GPU compatibility we just remove them entirely. They could be brought back if
an Embree compatible implementation is added, but it's not clear to me that there
is a use case for these that we'd consider important.
Ref T73778
Reviewers: #cycles
Subscribers:
OSLRenderServices contains a member which is 64 bytes aligned and this
is onlys supported by default allocators in SDK 10.14. Since we take
care of allocation ourselves ignoring the diagnostic is an acceptable
way dealign with it.
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 code is currently only used for the Glossy Toon BSDF, but it's a generic
building block that might be used for other things in the future.
To see why the current code does not give a uniform distribution, consider that
it chooses both angles uniformly, but the smaller the angle from the center of
the cone is, the smaller the differential solid angle is (similar to how
sampling disks by choosing radius and phi uniformly does not work).
Differential Revision: https://developer.blender.org/D7948
A new user parameter can be used to shift the shadow terminator
towards the light source. With it, one can hide some of the
artifacts that appear on coarse meshes with smooth shading.
Note that this technique is not engery conserving.
This is based on the work by the Appleseed renderer team.
Differential Revision: https://developer.blender.org/D7634
The input data to the OptiX denoiser was clamped to 0..10000 as required, but it could easily
exceed that range with a high number of samples (since the data contains the overall sum). To
fix that, divide by the number of samples first and multiply it back in after the denoiser ran.
