Add a new shader node to control volume coefficients (scattering,
absorption and emission) directly, making it easier to model existing
volumes with measured data.
Pull Request: https://projects.blender.org/blender/blender/pulls/136287
The goal is to reduce the affect of the fmod() used in the noise code,
which was initially reported in the comment:
https://projects.blender.org/blender/blender/pulls/119884#issuecomment-1258902
Basic idea is to benefit from SIMD vectorization on CPU.
Tested on Linux i9-11900K and macOS on M2 Ultra, in both cases performance
after this change is very close to what it could be with the fmod() commented
out (the call itself, `p = p + precision_correction`).
On macOS the penalty of fmod() was about 10%, on Linux it was closer to 30%
when built with GCC-13. With Linux builds from the buildbot it is more like 18%.
The optimization is only done for 3d and 4d noise. It might be possible to
gain some performance improvement for 1d and 2d cases, but the approach would
need to be different: we'd need to optimize scalar version fmodf(). Maybe
tricks with integer cast will be faster (since we are a bit optimistic in the
kernel and do not guarantee exact behavior in extreme cases such as NaN inputs).
Pull Request: https://projects.blender.org/blender/blender/pulls/137109
This makes it possible to restore previous Blender 4.3 behavior of bump
mapping, where the large filter width was sometimes (ab)used to get a bevel
like effect on stepwise textures.
For bump from the displacement socket, filter width remains fixed at 0.1.
Ref #133991, #135841
Pull Request: https://projects.blender.org/blender/blender/pulls/136465
This is an intermediate steps towards making lights actual geometry.
Light is now a subclass of Geometry, which simplifies some code.
The geometry is not added to the BVH yet, which would be the next
step and improve light intersection performance with many lights.
This makes object attributes work on lights.
Co-authored-by: Lukas Stockner <lukas@lukasstockner.de>
Pull Request: https://projects.blender.org/blender/blender/pulls/134846
The attribute handling code in the kernel is currently highly duplicated since
it needs to handle five different data types and we couldn't use templates
back then.
We can now, so might as well make use of it and get rid of ~1000 lines.
There are also some small fixes for the GPU OSL code:
- Wrong derivative for .w component when converting float2/float3->float4
- Different conversion for float2->float (CPU averages, GPU used to take .x)
- Removed useless code for converting to float2, not used by OSL
Pull Request: https://projects.blender.org/blender/blender/pulls/134694
In Cycles lights can be given a light falloff node to control their
light falloff.
This worked by multiplying the light's strength by different
combinations of the ray length, which would be FLT_MAX for
distant lights. This resulting in almost every configuration of the
light falloff node overflowing when used on distant lights, which is
undesirable.
This commit fixes this issue by ignoring most of the functions of the
light falloff node when used on a distant light.
And in the process fixes a small discrepancy between SVM and OSL when
using the light falloff node on distant lights.
Pull Request: https://projects.blender.org/blender/blender/pulls/134539
This commit fixes a issue where ray depth for emissive objects
(E.g. Lights) was incorrect when using the ray depth output of the
light path node in Cycles OSL.
Pull Request: https://projects.blender.org/blender/blender/pulls/134496
The derivatives of the normal were simply not computed.
The offsetted normals are computed by perturbating the barycentric
coordinates. At triangle boundaries, the normals are extrapolated,
so discontinuities might be visible.
Currently only supported on triangles.
Pull Request: https://projects.blender.org/blender/blender/pulls/133769
Use sub-pixel differentials for bump mapping helps with reducing
artifacts when objects are moving or when textures have high frequency
details.
Currently we scale it by 0.1 because it seems to work good in practice,
we can adjust the value in the future if it turns out to be impractical.
Ref: #122892
Pull Request: https://projects.blender.org/blender/blender/pulls/133991
- Rename dx/dy -> dfdx/dfdy to match the actual computed quantity
- Add template functions to compute dfdx/dfdy on triangles for sharing
among different data types
- Add documentation to some functions
- Some code shuffling that makes it easier to scale dfdx/dfdy in the
future
- Some other trivial changes
In a recent refactor (1), the subsurface weight was set to be
constant, when it can be modified in the case that `__SUBSURFACE__`
is false, such as when using the adaptive compilation feature.
This commit fixes this issue by rearranging the code so the subsurface
weight is never overwritten.
(1) blender/blender@dd51c8660b
Pull Request: https://projects.blender.org/blender/blender/pulls/132620
Check was misc-const-correctness, combined with readability-isolate-declaration
as suggested by the docs.
Temporarily clang-format "QualifierAlignment: Left" was used to get consistency
with the prevailing order of keywords.
Pull Request: https://projects.blender.org/blender/blender/pulls/132361
* Use .empty() and .data()
* Use nullptr instead of 0
* No else after return
* Simple class member initialization
* Add override for virtual methods
* Include C++ instead of C headers
* Remove some unused includes
* Use default constructors
* Always use braces
* Consistent names in definition and declaration
* Change typedef to using
Pull Request: https://projects.blender.org/blender/blender/pulls/132361
Previous implemenation of 5 < d < 50 was taken from the main paper,
fitting for smaller sizes are found in the supplemental. They are less
forward-scattering.
Pull Request: https://projects.blender.org/blender/blender/pulls/130234
`CLOSURE_WEIGHT_CUTOFF` avoids allocating a closure when its weight is
too small. It makes sense for surface closures, but for volume closures
the contribution also depends on the object size/ray length, such a
cutoff seems random and is causing problem in atmospheric scatterings.
Therefore remove the cutoff for volume, just make sure the weight is
positive.
Pull Request: https://projects.blender.org/blender/blender/pulls/131696
The `osl_wavelength_color_vf` intrinsic was missing an implementation for
OptiX, causing a link error when attempting to load OSL shaders using the
wavelength node.
Pull Request: https://projects.blender.org/blender/blender/pulls/129372
This packs the SVM stack, current node offset and closure weight into one struct, and just passes that to each SVM node implementation.
This way we don't have to pass the offset back and forth all over the place, and adding additional state (e.g. for layering in the future) becomes easier.
Pull Request: https://projects.blender.org/blender/blender/pulls/110443
- Deduplicate Fisheye projection code
- Replace spherical/cartesian conversions with shared helpers
- Replace transforms from/to local coordinate systems with shared helpers
The main type of repeated transform that's not covered here is `to/from_coords`, but with separate values for xy and z (e.g. BSDFs that already computed `dot(wi, N)` earlier, so they only need `dot(wi, X)` and `dot(wi, Y)` later). Could also be replaced, but it would feel weirdly specific for a helper function.
Pull Request: https://projects.blender.org/blender/blender/pulls/125999
Fixes a issue where the Principled BSDF would render incorrectly if
`__SUBSURFACE__` is off. Which is common when using adaptive kernel
compilation (a unsupported Cycles feature).
Pull Request: https://projects.blender.org/blender/blender/pulls/128003
Previously, Cycles only supported the Henyey-Greenstein phase function for volume scattering.
While HG is flexible and works for a wide range of effects, sometimes a more physically accurate
phase function may be needed for realism.
Therefore, this adds three new phase functions to the code:
Rayleigh: For particles with a size below the wavelength of light, mostly athmospheric scattering.
Fournier-Forand: For realistic underwater scattering.
Draine: Fairly specific on its own (mostly for interstellar dust), but useful for the next entry.
Mie: Approximates Mie scattering in water droplets using a mix of Draine and HG phase functions.
These phase functions can be combined using Mix nodes as usual.
Co-authored-by: Lukas Stockner <lukas@lukasstockner.de>
Pull Request: https://projects.blender.org/blender/blender/pulls/123532
`atan2(0, 0)` is undefined on many platforms. To ensure consistent
result across platforms, we return `0` in this case.
Note only the behavior of the shader node `Artan2` is changed here.
During shading, we might still produce `atan2(0, 0)` internally and
cause different results across platforms, but that usually happens with
single samples and is not obvious, plus checking this condition all the
time is costly. If later we find out it's indeed necessary to change all
the invocation of `atan2(0, 0)`, we could change the wrapper functions
in `metal/compat.h` and `mtl_shader_defines.msl`.
Pull Request: https://projects.blender.org/blender/blender/pulls/126951
Add Metallic BSDF Node to the shader editor.
This node can primarily be used to create more realistic looking
metallic materials than the existing Glossy BSDF node.
This commit does not add any new closures to Cycles, it simply exposes
existing closures that were previous hard to access on their own.
- Exposes the F82 fresnel type that is currently used by the
metallic component of the Principled BSDF. Results should match
between the Metallic BSDF and Principled BSDF when using the same
settings.
- Exposes the Physical Conductor fresnel type that was previously
limited to custom OSL scripts. The Conductor fresnel type accepts
IOR and Extinction coefficients to define the appearance of the
material based off real life measurements.
EEVEE only supports the F82 fresnel type with internal code to convert
the the physical conductor inputs in to a colour format for F82,
which can lead to noticeable rendering differences with
some configurations.
Pull Request: https://projects.blender.org/blender/blender/pulls/114958
This patch improves the isotropic Gabor noise UI controls such that
variations happen in both directions of the base orientation, as opposed
to being biased in the positive direction only.
Thanks to Charlie Jolly for suggesting this improvement.
This patch optimizes the Gabor noise standard deviation estimation by
computing the upper limit of the integral as the frequency approaches
infinity, since the integral is mostly constant for the relevant
frequency range. The limits are 0.25 for the 2D case and 1 / 4 * sqrt2
for the 3D case.
This also improves normalization for low frequencies, possibly due to
the effect of windowing.
Thanks to Charlie Jolly for spotting the optimization.
Optimize the Gabor noise texture code with an early exit for points that
are further away from the kernel center. This was already done for the
kernel, but is now being done earlier before computing the weight, so
its computation is now skipped.
Thanks to Charlie Jolly for the suggestion.
This decreases BSDF_ROUGHNESS_SQ_THRESH so that the microfacet
roughness has a cutoff at much lower values and fixes a precision
issue in the bsdf_sample code that prevented this previously.
Pull Request: https://projects.blender.org/blender/blender/pulls/125919
Align Cycles SVM and EEVEE's rendering of the vector math node
in reflect mode with OSL when the normal vector is 0,0,0.
This is done by using safe_normalize rather than normalize on the
normal vector. Which also fixes a NaN in the reflect mode in this
specific configuration.
Pull Request: https://projects.blender.org/blender/blender/pulls/125688
Setting this option to a value above zero replaces the lambertian Diffuse term
with the modified energy-preserving Oren-Nayar BSDF, which matches the OpenPBR
behavior.
Pull Request: https://projects.blender.org/blender/blender/pulls/123616
