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
This avoid having to guards functions that are
only available in fragment shader stage.
Calling the function inside another stage is still
invalid and will yield a compile error on Metal.
The vulkan and opengl glsl patch need to be modified
per stage to allow the fragment specific function
to be defined.
This is not yet widely used, but a good example is
the change in `film_display_depth_amend`.
Rel #137261
Pull Request: https://projects.blender.org/blender/blender/pulls/138280
Do this only when applicable.
This allow better compile time checking in Shader C++ compilation.
Moreover, this allows to have `constexpr` in shared code between
C++ and GLSL.
After investigation the `const` keyword in GLSL has the same
semantic than C/C++.
Rel #137333 and #137446
Pull Request: https://projects.blender.org/blender/blender/pulls/137497
This unify the C++ and GLSL codebase style.
The GLSL types are still in the backend compatibility
layers to support python shaders. However, the C++
shader compilation layer doesn't have them to enforce
correct type usage.
Note that this is going to break pretty much all PRs
in flight that targets shader code.
Rel #137261
Pull Request: https://projects.blender.org/blender/blender/pulls/137369
They are actually already some literals with the `f` suffix
that are in our shader codebase and we never had problem in
the past 5 years (or even 8 years).
So I think it is safe to do and improves convergence of codestyles.
Pull Request: https://projects.blender.org/blender/blender/pulls/137352
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
The Mix Color shader node does not retain the alpha channel of the first
input in both the Linear Light and Soft Light modes, while it is retain
for other modes. Further, result clamping also ignores the alpha due to
using the vector clamp function, which introduces implicit conversion
that removes the alpha.
This does not matter for EEVEE because it does nothing with the alpha
channel. But the code will now be shared with the compositor, which does
care about the alpha channel. So adjust the code accordingly to retain
the alpha in those cases.
Pull Request: https://projects.blender.org/blender/blender/pulls/135632
This patch refactors GPU shaders to remove includes to the utility
gpu_shader_common_math.glsl file. This is done because it has duplicate
functions that exist in other files, and it was really created for use
in GPU material nodes.
The safe_divide and hypot functions were removed since they exist in
gpu_shader_math_base_lib.glsl.
The compatible_[mod|pow] and wrap functions were moved into
gpu_shader_math_base_lib.glsl.
The floor_to_int function was inlined since it was trivial and only used
in one place.
The quick_floor was removed because it was unused.
The euler_to_mat3 function was replaced with the from_rotation function
from gpu_shader_math_matrix_lib.glsl.
Now the file only contains some GPU material node utility functions.
Pull Request: https://projects.blender.org/blender/blender/pulls/135160
Though "Point Cloud" written as two words is technically correct and should be used in the UI, as one word it's typically easier to write and parse when reading. We had a mix of both before this patch, so better to unify this as well.
This commit also renames the editor/intern/ files to remove pointcloud_ prefix.
point_cloud was only preserved on the user facing strings:
* is_type_point_cloud
* use_new_point_cloud_type
Pull Request: https://projects.blender.org/blender/blender/pulls/134803
This commit adds the "is volume scatter" output to the light path node
in the shader editor.
All the funcitonal code for this feature already exists in Cycles SVM
and OSL, but the output wasn't exposed on the node.
EEVEE does not support the feature, so it's output will
always be zero.
Pull Request: https://projects.blender.org/blender/blender/pulls/134343
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
Color to grayscale conversions should take into account the colorspace,
and these are considered to be in scene linear colorspace.
Note the RBG to BW node implementation is used for implicit conversions,
so that is covered as well.
No change with the default configuration.
Pull Request: https://projects.blender.org/blender/blender/pulls/133368
Move most of the string preprocessing used for MSL
compatibility to `glsl_preprocess`.
Enforce some changes like matrix constructor and
array constructor to the GLSL codebase. This is
for C++ compatibility.
Additionally reduce the amount of code duplication
inside the compatibility code.
Pull Request: https://projects.blender.org/blender/blender/pulls/128634
This changes the include directive to use the standard C preprocessor
`#include` directive.
The regex to applied to all glsl sources is:
`pragma BLENDER_REQUIRE\((\w+\.glsl)\)`
`include "$1"`
This allow C++ linter to parse the code and allow easier codebase
traversal.
However there is a small catch. While it does work like a standard
include directive when the code is treated as C++, it doesn't when
compiled by our shader backends. In this case, we still use our
dependency concatenation approach instead of file injection.
This means that included files will always be prepended when compiled
to GLSL and a file cannot be appended more than once.
This is why all GLSL lib file should have the `#pragma once` directive
and always be included at the start of the file.
These requirements are actually already enforced by our code-style
in practice.
On the implementation, the source needed to be mutated to comment
the `#pragma once` and `#include`. This is needed to avoid GLSL
compiler error out as this is an extension that not all vendor
supports.
Rel #127983
Pull Request: https://projects.blender.org/blender/blender/pulls/128076
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
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.
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
Fixes a mismatch between Cycles and EEVEE when rendering a
Vector Math node in Refract mode with a normal vector of 0,0,0.
This mismatch first appeared after 8650068f0c which changed the
behaviour in Cycles, but not EEVEE.
Pull Request: https://projects.blender.org/blender/blender/pulls/125644
color was not taken into consideration when picking a closure using
reservoir sampling, giving closures with dark color much higher weights
than they should have.
This fix multiplies the weight by the average color when picking the
closure, similar as what has been done in principled BSDF.
Pull Request: https://projects.blender.org/blender/blender/pulls/124730
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
With the new closure approach, the code can be simplified and cleaned up quite
a bit.
This also removes four parameters, which is helpful for future additions (!123616)
since the parameter limit appears to be reached.
Pull Request: https://projects.blender.org/blender/blender/pulls/123643
This patch implements a new Gabor noise node based on [1] but with the
improvements from [2] and the phasor formulation from [3].
We compare with the most popular existing implementation, that of OSL,
from the user's point of view:
- This implementation produces C1 continuous noise as opposed to the
non continuous OSL implementation, so it can be used for bump
mapping and is generally smother. This is achieved by windowing the
Gabor kernel using a Hann window.
- The Bandwidth input of OSL was hard-coded to 1 and was replaced with
a frequency input, which OSL hard codes to 2, since frequency is
more natural to control. This is even more true now that that Gabor
kernel is windowed as opposed to truncated, which means increasing
the bandwidth will just turn the Gaussian component of the Gabor
into a Hann window. While decreasing the bandwidth will eliminate
the harmonic from the Gabor kernel, which is the point of Gabor
noise.
- OSL had three discrete modes of operation for orienting the kernel.
Anisotropic, Isotropic, and a hybrid mode. While this implementation
provides a continuous Anisotropy parameter which users are already
familiar with from the Glossy BSDF node.
- This implementation provides not just the Gabor noise value, but
also its phase and intensity components. The Gabor noise value is
basically sin(phase) * intensity, but the phase is arguably more
useful since it does not suffer from the low contrast issues that
Gabor suffers from. While the intensity is useful to hide the
singularities in the phase.
- This implementation converges faster that OSL's relative to the
impulse count, so we fix the impulses count to 8 for simplicitly.
- This implementation does not implement anisotropic filtering.
Future improvements to the node includes implementing surface noise and
filtering. As well as extending the spectral control of the noise,
either by providing specialized kernels as was done in #110802, or by
providing some more procedural control over the frequencies of the
Gabor.
References:
[1]: Lagae, Ares, et al. "Procedural noise using sparse Gabor
convolution." ACM Transactions on Graphics (TOG) 28.3 (2009): 1-10.
[2]: Tavernier, Vincent, et al. "Making gabor noise fast and
normalized." Eurographics 2019-40th Annual Conference of the European
Association for Computer Graphics. 2019.
[3]: Tricard, Thibault, et al. "Procedural phasor noise." ACM
Transactions on Graphics (TOG) 38.4 (2019): 1-13.
Pull Request: https://projects.blender.org/blender/blender/pulls/121820
This was a missing block of the TAA implementation.
TAA jitter and reprojection have a tedency to soften
the texture. Add a 1.5 bias to make them a bit sharper.
Note that this is a bit different than the usual TAA
blurring. In final render we don't do reprojection
so it is only because the texture filter (box filter
from the LOD) is applied at the same time than our pixel
filter (blackmann-harris). It is less noticeable than
the normal TAA blur, but still blurs ~2px instead of
1.5px.
The previous code was using matrix multiplication to
get the local thickness to world thickness.
The correct way is to multiply the local thickness
by the scale of the object (length of each columns
of the object_to_world matrix).
Fix for #121890
The image shows testing results with "green" texture. It is expected that
all vectors are displaced along Y axis.
Cases are "no displacement", "tangent", "object" and "world" spaces.
Results are consistent with Cycles.
Pull Request: https://projects.blender.org/blender/blender/pulls/122376
One of the properties of Perlin noise is that it always evaluates to 0.0
when not normalized (or 0.5 when normalized) when the input consists of
only whole integers in all vector components.
Blender's Perlin noise implementation uses single precision floats with
a machine epsilon of 1.19e-07 meaning that for numbers that are greater
than 1/(1.19e-07) = 8.40e6 there mantissa doesn't have any bits left to
store a rational part of the number, effectively meaning that any number
greater than 8.40e6 is a whole integer as far as Blender is concerned.
Therefore when evaluating Perlin noise for any coordinates greater than
that it always results in 0.0 (or 0.5 when normalized).
This fix works as follows: If the original input number is larger than
1.0e6 it is offset by 0.5 after it underwent modulo, which always outputs
numbers in a [0.0, 1.0e5) range leaving the mantissa room for a rational
part. This way the quantization error still persists however the outputs
are random again instead of a constant 0.0.
Pull Request: https://projects.blender.org/blender/blender/pulls/122112
This is an implementation of thin film iridescence in the Principled BSDF based on "A Practical Extension to Microfacet Theory for the Modeling of Varying Iridescence".
There are still several open topics that are left for future work:
- Currently, the thin film only affects dielectric Fresnel, not metallic. Properly specifying thin films on metals requires a proper conductive Fresnel term with complex IOR inputs, any attempt of trying to hack it into the F82 model we currently use for the Principled BSDF is fundamentally flawed. In the future, we'll add a node for proper conductive Fresnel, including thin films.
- The F0/F90 control is not very elegantly implemented right now. It fundamentally works, but enabling thin film while using a Specular Tint causes a jump in appearance since the models integrate it differently. Then again, thin film interference is a physical effect, so of course a non-physical tweak doesn't play nicely with it.
- The white point handling is currently quite crude. In short: The code computes XYZ values of the reflectance spectrum, but we'd need the XYZ values of the product of the reflectance spectrum and the neutral illuminant of the working color space. Currently, this is addressed by just dividing by the XYZ values of the illuminant, but it would be better to do a proper chromatic adaptation transform or to use the proper reference curves for the working space instead of the XYZ curves from the paper.
Pull Request: https://projects.blender.org/blender/blender/pulls/118477
This was caused by the 2 transmission event approximation we
do for object with non-null thickness. This follows cycles
by using the square root of the color.
Transport rays that enter to another location in the scene, with
specified ray position and normal. This may be used to render portals
for visual effects, and other production rendering tricks.
This acts much like a Transparent BSDF. Render passes are passed
through, and this is affected by light path max transparent bounces.
Pull Request: https://projects.blender.org/blender/blender/pulls/114386
Clamp some of the inputs of the Glossy BSDF, Glass BSDF, Sheen BSDF,
and Subsurface Scattering nodes to improve consistency between render
engines and to avoid unexpected results.
* Clamp roughness to 0..1
* Clamp subsurface radius to 0..inf
* Clamp colors to 0..inf
Pull Request: https://projects.blender.org/blender/blender/pulls/120390
