Overall, this commit reworks the component layering in the Principled BSDF
in order to ensure that energy is preserved and conserved.
This includes:
- Implementing support for the OSL `layer()` function
- Implementing albedo estimation for some of the closures for layering purposes
- The specular layer that the Principled BSDF uses has a proper tabulated
albedo lookup, the others are still approximations
- Removing the custom "Principled Diffuse" and replacing it with the classic
lambertian Diffuse, since the layering logic takes care of energy now
- Making the merallic component independent of the IOR
Note that this changes the look of the Principled BSDF noticeably in some
cases, but that's needed, since the cases where it looks different are the
ones that strongly violate energy conservation (mostly grazing reflections
with strong Specular).
Pull Request: https://projects.blender.org/blender/blender/pulls/110864
Many calls to add_check_c_compiler_flag add_check_cxx_compiler_flag
resulted in over long lines & visual noise. Replace with a function that
takes multiple (cache_var flag) pairs to reduce duplication.
Both the `Math` node and the `Vector Math` currently only explicitly
support modulo using truncated division which is oftentimes not the
type of modulo desired as it behaves differently for negative numbers
and positive numbers.
Floored Modulo can be created by either using the `Wrap` operation or
a combination of multiple `Math` nodes. However both methods obfuscate
the actual intend of the artist and the math operation that is actually
used.
This patch adds modulo using floored division to the scalar `Math` node,
explicitly stating the intended math operation and renames the already
existing `"Modulo"` operation to `"Truncated Modulo"` to avoid confusion.
Only the ui name is changed, so this should not break compatibility.
Pull Request: https://projects.blender.org/blender/blender/pulls/110728
The current core was only detecting sRGB transform when it is defined
as sRGB->Linear using srgb.spi1d. If it is defined as an inverse of
Linear->sRGB using srgb_inv.spi1d, or as an analytical formula using
ExponentWithLinearTransform then the code did not detect the color
as sRGB on anything by Apple Silicon platform.
The naming of the checks could be improved to make it more clear that
the check is only used to allow lossless access to 8bit sRGB textures.
Ref #110685
Pull Request: https://projects.blender.org/blender/blender/pulls/110889
This pull request covers up a subtle difference between the CPU and GPU
when rendering with a light tree. Specifically a case where the user
has a sun light with a small angle.
The difference was caused by the dot() function being different between
CPU and GPU backends, with the GPU showing more meaningful
floating-point precision losses when working with small suns.
Pull Request: https://projects.blender.org/blender/blender/pulls/110307
The issue was an out-of-bounds read access when checking whether
the world volume emission needs to be accumulated.
Solution is to check for this case. Done in the generic place, so
that the shade_volume kernel is more readable and no branching
added there, and there is no impact on scenes without the light
linking.
Assume that the world emissive volume belongs to the default light
linking group, as there is no way to link it explicitly to anything.
Pull Request: https://projects.blender.org/blender/blender/pulls/110733
This replaces the Sheen model used in the Principled BSDF with the
model from #108869 that is already used in the Sheen BSDF now.
The three notable differences are:
- At full intensity (Sheen = 1.0), the new model is significantly
stronger than the old one. For existing files, the intensity is
adjusted to keep the overall look similar.
- The Sheen Tint input is now a color input, instead of the
previous blend factor between white and the base color.
- There is now a Sheen roughness control, which can be used to
tweak the look between velvet-like and dust-like.
Pull Request: https://projects.blender.org/blender/blender/pulls/109949
MSVC_VER 1937 included 17.7 preview 1 and 2 that didn't support the flag
while developers may be using these versions already because of the
issues with 17.6. We now check for preview 3 specifically.
Starting with MSVC 17.7 preview 3, /jumptablerdata is available and
allows to ensure switch tables don't get mixed with the code, helping on
performance when there is contention in a large switch statement, such
as in svm.h.
Pull Request: https://projects.blender.org/blender/blender/pulls/110470
The cleanup of blenkernel last weeks , caused the house of cards to
collapse on top of bf_gpu's shader_builder, which is off by default
but used on a daily basis by the rendering team.
Given the fixes forward in #110394 ran into a ODR violation in OSL that
was hiding there for years, I don't see another way forward without
impeding the rendering teams productivity for "quite a while" as there
is no guarantee the OSL issue would be the end of it.
the only way forward appears to be back.
this reverts :
19422044eda670b53abe0f541db97cbe516e8c813e88a2f44c4e64b772f59547e7a31707fe6c5a57
The problematic commit was 07fe6c5a57
as blenkernel links most of blender, it's a bit of a link order issue
magnet. Given all these commits stack, it's near impossible to revert
just that one without spending a significant amount of time resolving
merge conflicts. 99% of that work was automated, so easier to just
revert all of them, and re-do the work, than it is to deal with the
merge conflicts.
Pull Request: https://projects.blender.org/blender/blender/pulls/110438
<algorithm> header include is missing from some sycl headers, this will
be fixed upstream with https://github.com/intel/llvm/pull/10424,
meanwhile, we work around it by including it directly.
Implements part of #101689.
The "poly" name was chosen to distinguish the `MLoop` + `MPoly`
combination from the `MFace` struct it replaced. Those two structures
persisted together for a long time, but nowadays `MPoly` is gone, and
`MFace` is only used in some legacy code like the particle system.
To avoid unnecessarily using a different term, increase consistency
with the UI and with BMesh, and generally make code a bit easier to
read, this commit replaces the `poly` term with `poly`. Most variables
that use the term are renamed too. `Mesh.totface` and `Mesh.fdata` now
have a `_legacy` suffix to reduce confusion. In a next step, `pdata`
can be renamed to `face_data` as well.
Pull Request: https://projects.blender.org/blender/blender/pulls/109819
This is only used as temporary state while evaluating SVM nodes,
there's no point in storing it in the ShaderData for later.
Since ShaderData size is relevant for GPU performance, we should
save the space and only keep it where needed.
Pull Request: https://projects.blender.org/blender/blender/pulls/110366
There's no reason why this would need to be its own closure, it was
just a slightly different microfacet distribution with a hardcoded
IOR and intensity multiplier internally.
No functional change, just cleaning up the mess of custom OSL closures.
Pull Request: https://projects.blender.org/blender/blender/pulls/109951
This was already unsupported in combination with Multiscattering GGX,
prevented the Principled BSDF from using microfaced-based Fresnel for
Glass materials, and would have made future improvements even trickier.
Pull Request: https://projects.blender.org/blender/blender/pulls/109950
Previously Glass Fresnel used to get baked into the closure weight,
so the MNEE code could just ignore it.
However, now that it's part of the closure implementation, we need
to account for it in the MNEE throughput calculation as well.
Previously the normal strength linearly interpolated and extrapolated
the normal in world space. Instead do it in tangent space, in a way
that ensure the normal remains above the surface and valid.
Pull Request: https://projects.blender.org/blender/blender/pulls/109763
Changes to the kernel source would not update the HIP RT binaries, leading
to render errors due to the kernel being mismatched with Blender.
The code this was copied from was inside a macro that defines the sources
variable, but it's not defined here.
Ref #109418
Pull Request: https://projects.blender.org/blender/blender/pulls/110073
this option was already unselectable in the UI, and is treated as GGX
with zero roughness. Upon building the shader graph, we only convert a
closure to `SHARP` when option Filter Glossy is not used and the
roughness is below certain threshold. The benefit is that we can avoid
calling `bsdf_eval()` or return earlier in some cases, but the thresholds
vary across files.
This patch removes `SHARP` closures altogether, and checks if the
roughness value is below a global threshold `BSDF_ROUGHNESS_THRESH`
after blurring, in which case the flag `SD_BSDF_HAS_EVAL` is not set.
The global threshold is set to be `5e-7f` because threshold smaller than
that seems to have caused problem in the past (c6aa0217ac). Also removes
a bunch of functions, variables and arguments that were only there
because we converted closures under certain conditions.
Pull Request: https://projects.blender.org/blender/blender/pulls/109902
