Materials now have an enum to set the emission sampling method, to be
either None, Auto, Front, Back or Front & Back. This replace the
previous "Multiple Importance Sample" option.
Auto is the new default, and uses a heuristic to estimate the emitted
light intensity to determine of the mesh should be considered as a light
for sampling. Shaders sometimes have a bit of emission but treating them
as a light source is not worth the memory/performance overhead.
The Front/Back settings are not important yet, but will help when a
light tree is added. In that case setting emission to Front only on
closed meshes can help ignore emission from inside the mesh interior that
does not contribute anything.
Includes contributions by Brecht Van Lommel and Alaska.
Ref T77889
This patch generalizes the OSL support in Cycles to include GPU
device types and adds an implementation for that in the OptiX
device. There are some caveats still, including simplified texturing
due to lack of OIIO on the GPU and a few missing OSL intrinsics.
Note that this is incomplete and missing an update to the OSL
library before being enabled! The implementation is already
committed now to simplify further development.
Maniphest Tasks: T101222
Differential Revision: https://developer.blender.org/D15902
Simplifies code overall to do it inside the eval function, most of the BSDFs
already compute the dot product.
The refactoring in bsdf_principled_hair_eval() was needed to avoid a HIP
compiler bug. Cause is unclear, just changing the implementation enough
is meant to sidestep it.
Ref T92571, D15286
* Return roughness and IOR for BSDF sampling
* Add functions to query IOR and label for given BSDF
* Default IOR to 1.0 instead of 0.0 for BSDFs that don't use it
* Ensure pdf >= 0.0 in case of numerical precision issues
Ref T92571, D15286
Cleans up the file structure to be more similar to that of the SVM
and also makes it possible to build kernels with OSL support, but
without having to include SVM support.
This patch was split from D15902.
Differential Revision: https://developer.blender.org/D15949
This has the advantage of being able to use information about the
existing OSL closures in various places without code duplication. In
addition, the setup code for all closures was moved to standalone
functions to avoid usage of virtual function calls in preparation for GPU
support.
This patch was split from D15902.
Differential Revision: https://developer.blender.org/D15917
* Store compact ray differentials in ShaderData and compute full differentials
on demand. This reduces register pressure on the GPU.
* Remove BSDF differential code that was effectively doing nothing as the
differential orientation was discarded when making it compact.
This gives a 1-5% speedup with RTX A6000 + OptiX in our benchmarks, with the
bigger speedups in simpler scenes.
Renders appear to be identical except for the Both displacement option that
does both displacement and bump.
Differential Revision: https://developer.blender.org/D15677
These replace float3 and packed_float3 in various places in the kernel where a
spectral color representation will be used in the future. That representation
will require more than 3 channels and conversion to from/RGB. The kernel code
was refactored to remove the assumption that Spectrum and RGB colors are the
same thing.
There are no functional changes, Spectrum is still a float3 and the conversion
functions are no-ops.
Differential Revision: https://developer.blender.org/D15535
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 unifies the names of math functions for different data types and uses
overloading instead. The goal is to make it possible to swap out all the float3
variables containing RGB data with something else, with as few as possible
changes to the code. It's a requirement for future spectral rendering patches.
Differential Revision: https://developer.blender.org/D15276
* Rename "texture" to "data array". This has not used textures for a long time,
there are just global memory arrays now. (On old CUDA GPUs there was a cache
for textures but not global memory, so we used to put all data in textures.)
* For CUDA and HIP, put globals in KernelParams struct like other devices.
* Drop __ prefix for data array names, no possibility for naming conflict now that
these are in a struct.
The Multiscatter GGX code was missing the same-side checks for incoming and
outgoing directions w.r.t. to shading and geometry normal.
Should not be needed for the Glass variant since it intentionally has both
reflection and transmission.
Currently, the `eval` and `pdf` are not explicitly set to zero when a BSDF sample is invalid (e.g., below the upper hemisphere), when calling
`bsdf_sample` or `bsdf_eval`. It is assumed that `eval` and `pdf` are set to zero before these functions are called, which can cause problems if not.
This patch fixes this potential problem by explicitly setting `eval` and `pdf` to zero when the sampled direction is invalid.
I also added a sanity check if `eval` and `pdf` are valid (i.e., >= 0.f).
The check is activated when build in debug mode and with the `WITH_CYCLES_DEBUG` set to `ON`.
Reviewed By: brecht, sergey
Differential Revision: https://developer.blender.org/D14776
A zero length vector was normalized and the resulting NaN used in further calculations.
This caused trouble on some compilers when using fast math.
Reviewed By: brecht, sergey
Differential Revision: https://developer.blender.org/D14058
* 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
saturate is depricated in favour of __saturatef this replaces saturate
with __saturatef on CUDA by createing a saturatef function which replaces
all instances of saturate and are hooked up to the correct function on all
platforms.
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D13010
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.
* Split render/ into scene/ and session/. The scene/ folder now contains the
scene and its nodes. The session/ folder contains the render session and
associated data structures like drivers and render buffers.
* Move top level kernel headers into new folders kernel/camera/, kernel/film/,
kernel/light/, kernel/sample/, kernel/util/
* Move integrator related kernel headers into kernel/integrator/
* Move OSL shaders from kernel/shaders/ to kernel/osl/shaders/
For patches and branches, git merge and rebase should be able to detect the
renames and move over code to the right file.
Need to initialize components for the full Diffuse BSDF.
Steps to reproduce:
- Default cube scene
- Switch to Cycles renderer
- Enable OSL backend
- Start viewport render
- Observe cube being much black
Differential Revision: https://developer.blender.org/D12921
* Rename struct KernelGlobals to struct KernelGlobalsCPU
* Add KernelGlobals, IntegratorState and ConstIntegratorState typedefs
that every device can define in its own way.
* Remove INTEGRATOR_STATE_ARGS and INTEGRATOR_STATE_PASS macros and
replace with these new typedefs.
* Add explicit state argument to INTEGRATOR_STATE and similar macros
In preparation for decoupling main and shadow paths.
Differential Revision: https://developer.blender.org/D12888
This is the first of a sequence of changes to support compiling Cycles kernels as MSL (Metal Shading Language) in preparation for a Metal GPU device implementation.
MSL requires that all pointer types be declared with explicit address space attributes (device, thread, etc...). There is already precedent for this with Cycles' address space macros (ccl_global, ccl_private, etc...), therefore the first step of MSL-enablement is to apply these consistently. Line-for-line this represents the largest change required to enable MSL. Applying this change first will simplify future patches as well as offering the emergent benefit of enhanced descriptiveness.
The vast majority of deltas in this patch fall into one of two cases:
- Ensuring ccl_private is specified for thread-local pointer types
- Ensuring ccl_global is specified for device-wide pointer types
Additionally, the ccl_addr_space qualifier can be removed. Prior to Cycles X, ccl_addr_space was used as a context-dependent address space qualifier, but now it is either redundant (e.g. in struct typedefs), or can be replaced by ccl_global in the case of pointer types. Associated function variants (e.g. lcg_step_float_addrspace) are also redundant.
In cases where address space qualifiers are chained with "const", this patch places the address space qualifier first. The rationale for this is that the choice of address space is likely to have the greater impact on runtime performance and overall architecture.
The final part of this patch is the addition of a metal/compat.h header. This is partially complete and will be extended in future patches, paving the way for the full Metal implementation.
Ref T92212
Reviewed By: brecht
Maniphest Tasks: T92212
Differential Revision: https://developer.blender.org/D12864
For details see the "Extending the Disney BRDF to a BSDF with Integrated
Subsurface Scattering" paper.
We split the diffuse BSDF into a lambertian and retro-reflection component.
The retro-reflection component is always handled as a BSDF, while the
lambertian component can be replaced by a BSSRDF.
For the BSSRDF case, we compute Fresnel separately at the entry and exit
points, which may have different normals. As the scattering radius decreases
this converges to the BSDF case.
A downside is that this increases noise for subsurface scattering in the
Principled BSDF, due to some samples going to the retro-reflection component.
However the previous logic (also in 2.93) was simple wrong, using a
non-sensical view direction vector at the exit point. We use an importance
sampling weight estimate for the retro-reflection to try to better balance
samples between the BSDF and BSSRDF.
Differential Revision: https://developer.blender.org/D12801
There is not enough time before the release to improve Random Walk to handle
all cases this was used for, so restore it for now.
Since there is no more path splitting in cycles-x, this can increase noise in
non-flat areas for the sample number of samples, though fewer rays will be traced
also. This is fundamentally a trade-off we made in the new design and why Random
Walk is a better fit. However the importance resampling we do now does help to
reduce noise.
Differential Revision: https://developer.blender.org/D12800
Fixes:{T91064}
Caused by {rBcd118c5581f482afc8554ff88b5b6f3b552b1682}
- Applies `ensure_valid_reflection()` to the normal input on all BSDFs for CPU and GPU.
- This doesn't affect hair.
- Removes `ensure_valid_reflection()` from the output of Bump Map and Normal Map nodes for CPU/GPU as it is not needed.
- The fix doesn't touch OSL.
Reviewed By: brecht, leesonw
Maniphest Tasks: T91064
Differential Revision: https://developer.blender.org/D12403
This includes much improved GPU rendering performance, viewport interactivity,
new shadow catcher, revamped sampling settings, subsurface scattering anisotropy,
new GPU volume sampling, improved PMJ sampling pattern, and more.
Some features have also been removed or changed, breaking backwards compatibility.
Including the removal of the OpenCL backend, for which alternatives are under
development.
Release notes and code docs:
https://wiki.blender.org/wiki/Reference/Release_Notes/3.0/Cycleshttps://wiki.blender.org/wiki/Source/Render/Cycles
Credits:
* Sergey Sharybin
* Brecht Van Lommel
* Patrick Mours (OptiX backend)
* Christophe Hery (subsurface scattering anisotropy)
* William Leeson (PMJ sampling pattern)
* Alaska (various fixes and tweaks)
* Thomas Dinges (various fixes)
For the full commit history, see the cycles-x branch. This squashes together
all the changes since intermediate changes would often fail building or tests.
Ref T87839, T87837, T87836
Fixes T90734, T89353, T80267, T80267, T77185, T69800
Solves an error in the principled diffuse BSDF, where it was not correctly
rejecting directions outside the hemisphere.
Differential Revision: https://developer.blender.org/D12283
Offset rays from the flat surface to match where they would be for a smooth
surface as specified by the normals. In the shading panel there is now a
Shading Offset (existing option) and Geometry Offset (new).
The Geometry Offset works as follows:
* 0: disabled
* 0.001: only terminated triangles (normal points to the light, geometry
doesn't) are affected
* 0.1 (default): triangles at grazing angles are affected, and the effect
fades out
* 1: all triangles are affected
Limitations:
* The artifact is still visible in some cases, it could be that some quads
require to be treated specifically as quads.
* Inconsistent normals cause artifacts.
* If small objects cast shadows to a big low poly surface, the shadows can
appear to be in a wrong place - because the surface moved slightly above
the geometry. This can be noticed only at grazing angles to light.
* Approximated surfaces of two non-intersecting low-poly objects can overlap
that causes off-the-wall shadows.
Generally, using one or a few levels of subdivision can get rid of artifacts
faster than before.
Differential Revision: https://developer.blender.org/D11065
Was causing calculation issues later on in the kernel.
This change catches the most obvious case: missing attribute. The old
code was trying to set tangent to 0, but because it was transformed as
a normal it got converted to non-finite value. This change makes it so
that no transform is involved and 0 is written directly to the SVM
stack.
To cover all cases it will require using safe_normalize() in this node
and in the normal transform function. This is more involved change from
performance point of view, would be nice to verify whether we really want
to go this route.
I've left asserts in the BSDF allocation functions. Don't have strong
connection to them, but think they are handy and are not different from
having an assert in the path radiance checks.
Differential Revision: https://developer.blender.org/D11235
It is possible that BSDF allocation will advance pointer in the
allocation "pool" but will return null pointer if the weight is
too small.
One artist-measurable issue this change fixes is random issues
with denoising: normal pass for denoising could have accessed
non-initialized normal of a closure.
Differential Revision: https://developer.blender.org/D11230
