In T93382, the problem was that the Blender-side rendering code was
still generating the subsurface passes because the old render pass
flags were set, even though Cycles doesn't generate them anymore.
After a closer look, it turns out that the entire hardcoded pass
creation code can be removed. We already have an Engine API function
to query the list of render passes from the engine, so we might as
well just call that and create the returned passes.
Turns out that Eevee already did this anyways. On the Cycles side, it
allows to deduplicate a lot of `BlenderSync::sync_render_passes`.
Before, passes were defined in engine.py and in sync.cpp. Now, all
passes that engine.py returns are created automatically, so sync.cpp
only needs to handle a few special cases.
I'm not really concerned about affecting external renderer addons,
since they already needed to handle the old "builtin passes" in
their Engine API implementation anyways to make them show up in the
compositor. So, unless they missed that for like 10 releases, they
should not notice any difference.
Differential Revision: https://developer.blender.org/D16295
The attribute node already allows accessing attributes associated
with objects and meshes, which allows changing the behavior of the
same material between different objects or instances. The same idea
can be extended to an even more global level of layers and scenes.
Currently view layers provide an option to replace all materials
with a different one. However, since the same material will be applied
to all objects in the layer, varying the behavior between layers while
preserving distinct materials requires duplicating objects.
Providing access to properties of layers and scenes via the attribute
node enables making materials with built-in switches or settings that
can be controlled globally at the view layer level. This is probably
most useful for complex NPR shading and compositing. Like with objects,
the node can also access built-in scene properties, like render resolution
or FOV of the active camera. Lookup is also attempted in World, similar
to how the Object mode checks the Mesh datablock.
In Cycles this mode is implemented by replacing the attribute node with
the attribute value during sync, allowing constant folding to take the
values into account. This means however that materials that use this
feature have to be re-synced upon any changes to scene, world or camera.
The Eevee version uses a new uniform buffer containing a sorted array
mapping name hashes to values, with binary search lookup. The array
is limited to 512 entries, which is effectively limitless even
considering it is shared by all materials in the scene; it is also
just 16KB of memory so no point trying to optimize further.
The buffer has to be rebuilt when new attributes are detected in a
material, so the draw engine keeps a table of recently seen attribute
names to minimize the chance of extra rebuilds mid-draw.
Differential Revision: https://developer.blender.org/D15941
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
The multi-dimensional Sobol pattern required us to carefully use as low
dimensions as possible, as quality goes down in higher dimensions. Now that we
have two sampling patterns that are at least as good, there is no need to keep
it around and the implementation can be simplified.
Differential Revision: https://developer.blender.org/D15788
Use lowercase rgba channel names which still by-passes lossy nature
of DWA compression and which also keeps external compositing tools
happy.
Thanks Steffen Dünner for testing this patch!
Differential Revision: https://developer.blender.org/D15834
The DWA compression code in OpenEXR has hardcoded rules which decides
which channels are lossy or lossless. There is no control over these
rules via API.
This change makes it so channel names of xyzw is used for cryptomatte
passes in Cycles. This works around the hardcoded rules in the DWA code
making it so lossless compression is used. It is important to use lower
case y channel name as the upper case Y uses lossy compression.
The change in the channel naming also makes it so the write code uses
32bit for the cryptomatte even when saving half-float EXR.
Fixes T96933: Cryptomatte layers saved incorrectly with EXR DWA compression
Fixes T88049: Cryptomatte EXR Output Bit Depth should always be 32bit
Differential Revision: https://developer.blender.org/D15823
This adds support for rendering motion blur for volumes, using their
velocity field. This works for fluid simulations and imported VDB
volumes. For the latter, the name of the velocity field can be set per
volume object, with automatic detection of velocity fields that are
split into 3 scalar grids.
A new parameter is also added to scale velocity for more artistic control.
Like for Alembic and USD caches, a parameter to set the unit of time in
which the velocity vectors are expressed is also added. For Blender gas
simulations, the velocity unit should always be in seconds, so this is
only exposed for volume objects which may come from external OpenVDB
files.
These parameters are available under the `Render` panels for the fluid
domain and the volume object data properties respectively.
Credits: kernel advection code from Tangent Animation's Blackbird based
on earlier work by Geraldine Chua
Differential Revision: https://developer.blender.org/D14629
Light groups are a type of pass that only contains lighting from a subset of light sources.
They are created in the View layer, and light sources (lamps, objects with emissive materials
and/or the environment) can be assigned to a group.
Currently, each light group ends up generating its own version of the Combined pass.
In the future, additional types of passes (e.g. shadowcatcher) might be getting their own
per-lightgroup versions.
The lightgroup creation and assignment is not Cycles-specific, so Eevee or external render
engines could make use of it in the future.
Note that Lightgroups are identified by their name - therefore, the name of the Lightgroup
in the View Layer and the name that's set in an object's settings must match for it to be
included.
Currently, changing a Lightgroup's name does not update objects - this is planned for the
future, along with other features such as denoising for light groups and viewing them in
preview renders.
Original patch by Alex Fuller (@mistaed), with some polishing by Lukas Stockner (@lukasstockner97).
Differential Revision: https://developer.blender.org/D12871
While the correlation may not work well with adaptive sampling, in practice
this appears to work ok in most cases
Automatic scrambling distance uses the minimum samples from adaptive sampling,
which provides a good default estimate to avoid artifacts.
Contributed by Alaska.
Differential Revision: https://developer.blender.org/D13325
* 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
Make the Embree RTC_SCENE_FLAG_COMPACT flag optional and enabled per default.
Disabling it makes CPU rendering a bit faster in some scenes at the cost of a higher memory usage.
Barbershop renders about 3% faster, victor about 4% on CPU with compact BVH disabled.
Differential Revision: https://developer.blender.org/D13592
Consider temporary directory to be variant part of session configuration
which gets communicated to the tile manager on render reset.
This allows to be able to render with one temp directory, change the
directory, render again and have proper render result even with enabled
persistent data.
For the ease of access to the temp directory expose it via the render
engine API (engine.temp_directory).
Differential Revision: https://developer.blender.org/D13790
* Rename "Auto Tiles" to "Use Tiling", it's not really automatic and
confusing with the old auto tile size add-on.
* Rename "Adaptive" scrambling distance to "Automatic", to avoid confusion
with adaptive sampling.
This patch adds a CMake option "WITH_CYCLES_DEBUG" which builds cycles with
a feature that allows debugging/selecting the direct-light sampling strategy.
The same option may later be used to add other debugging features that could
affect performance in release builds.
The three options are:
* Forward path tracing (e.g., via BSDF or phase function)
* Next-event estimation
* Multiple importance sampling combination of the previous two methods
Such a feature is useful for debugging light different sampling, evaluation,
and pdf methods (e.g., for light sources and BSDFs).
Differential Revision: https://developer.blender.org/D13152
This patch exposes the sampling offset option to Blender. It is located in the "Sampling > Advanced" panel.
For example, this can be useful to parallelize rendering and distribute different chunks of samples for each computer to render.
---
I also had to add this option to `RenderWork` and `RenderScheduler` classes so that the sample count in the status string can be calculated correctly.
Reviewed By: leesonw
Differential Revision: https://developer.blender.org/D13086
The issue was that the `object_is_geometry` method was used in two different
contexts that expected the function to behave differently. So a recent change
that fixed `object_is_geometry` for one context, broke it for the other context.
The two contexts are:
* Check if a "real" object can contain a geometry to check if it has to be tagged
for sync after an update.
* Check if an object/instance actually is a geometry that cycles can work with.
I created a new `object_can_have_geometry` method for the first use case, instead
of trying to adapt the existing object_is_geometry method to serve both uses.
Additionally, I changed it so that a BObjectInfo is passed into `object_is_geometry`
to make it more explicit when this method is supposed to be used.
Differential Revision: https://developer.blender.org/D13135
The issue was that some geometries were not synced again even when
they changed. This commit adds a map that keeps track of the geometries
that need to be updated when an object has changed.
Differential Revision: https://developer.blender.org/D13020
Adds scrambling distance to the PMJ sampler. This is based
on the work by Mathieu Menuet in D12318 who created the original
implementation for the Sobol sampler.
Reviewed By: brecht
Maniphest Tasks: T92181
Differential Revision: https://developer.blender.org/D12854
Cycles:Distance Scrambling for Cycles Sobol Sampler
This option implements micro jittering an is based on the INRIA
research paper [[ https://hal.inria.fr/hal-01325702/document | on micro jittering ]]
and work by Lukas Stockner for implementing the scrambling distance.
It works by controlling the correlation between pixels by either using
a user supplied value or an adaptive algorithm to limit the maximum
deviation of the sample values between pixels.
This is a follow up of https://developer.blender.org/D12316
The PMJ version can be found here: https://developer.blender.org/D12511
Reviewed By: leesonw
Differential Revision: https://developer.blender.org/D12318
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.
