This adds path guiding features into Cycles by integrating Intel's Open Path
Guiding Library. It can be enabled in the Sampling > Path Guiding panel in the
render properties.
This feature helps reduce noise in scenes where finding a path to light is
difficult for regular path tracing.
The current implementation supports guiding directional sampling decisions on
surfaces, when the material contains a least one diffuse component, and in
volumes with isotropic and anisotropic Henyey-Greenstein phase functions.
On surfaces, the guided sampling decision is proportional to the product of
the incident radiance and the normal-oriented cosine lobe and in volumes it
is proportional to the product of the incident radiance and the phase function.
The incident radiance field of a scene is learned and updated during rendering
after each per-frame rendering iteration/progression.
At the moment, path guiding is only supported by the CPU backend. Support for
GPU backends will be added in future versions of OpenPGL.
Ref T92571
Differential Revision: https://developer.blender.org/D15286
This was tested in some places to check if code was being compiled for the
CPU, however this is only defined in the kernel. Checking __KERNEL_GPU__
always works.
This patch partitions the active indices into chunks prior to sorting by material in order to tradeoff some material coherence for better locality. On Apple Silicon GPUs (particularly higher end M1-family GPUs), we observe overall render time speedups of up to 15%. The partitioning is implemented by repeating the range of `shader_sort_key` for each partition, and encoding a "locator" key which distributes the indices into sorted chunks.
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D15331
* Replace license text in headers with SPDX identifiers.
* Remove specific license info from outdated readme.txt, instead leave details
to the source files.
* Add list of SPDX license identifiers used, and corresponding license texts.
* Update copyright dates while we're at it.
Ref D14069, T95597
Changes:
* After hitting a shadow catcher, re-initialize the volume stack taking
into account shadow catcher ray visibility. This ensures that volume objects
are included in the stack only if they are shadow catchers.
* If there is a volume to be shaded in front of the shadow catcher, the split
is now performed in the shade_volume kernel after volume shading is done.
* Previously the background pass behind a shadow catcher was done as part of
the regular path, now it is done as part of the shadow catcher path.
For a shadow catcher path with volumes and visible background, operations are
done in this order now:
* intersect_closest
* shade_volume
* shadow catcher split
* intersect_volume_stack
* shade_background
* shade_surface
The world volume is currently assumed to be CG, that is it does not exist in
the footage. We may consider adding an option to control this, or change the
default. With a volume object this control is already possible.
This includes refactoring to centralize the logic for next kernel scheduling
in intersect_closest.h.
Differential Revision: https://developer.blender.org/D13093
Remove prefix of filenames that is the same as the folder name. This used
to help when #includes were using individual files, but now they are always
relative to the cycles root directory and so the prefixes are redundant.
For patches and branches, git merge and rebase should be able to detect the
renames and move over code to the right file.
