Cycles ignores the size of spot lights, therefore the illuminated area doesn't match the gizmo. This patch resolves this discrepancy.
| Before (Cycles) | After (Cycles) | Eevee
|{F14200605}|{F14200595}|{F14200600}|
This is done by scaling the ray direction by the size of the cone. The implementation of `spot_light_attenuation()` in `spot.h` matches `spot_attenuation()` in `lights_lib.glsl`.
**Test file**:
{F14200728}
Differential Revision: https://developer.blender.org/D17129
The image manager used to handle OSL textures on the GPU by
default loads images after displacement is evaluated. This is a
problem when the displacement shader uses any textures, hence
why the geometry manager already makes the image manager
load any images used in the displacement shader graph early
(`GeometryManager::device_update_displacement_images`).
This only handled Cycles image nodes however, not OSL nodes, so
if any `texture` calls were made in OSL those would be missed and
therefore crash when accessed on the GPU. Unfortunately it is not
simple to determine which textures referenced by OSL are needed
for displacement, so the solution for now is to simply load all of
them early if true displacement is used.
This patch also fixes the result of the displacement shader not
being used properly in OptiX.
Maniphest Tasks: T104240
Differential Revision: https://developer.blender.org/D17162
The `MultiDevice` implementation of `get_cpu_osl_memory` returns a
nullptr when there is no CPU device in the mix. As such access to that
crashed in `update_osl_globals`. But that only updates maps that are not
currently used on the GPU anyway, so can just skip that when the CPU
is not used for rendering.
Maniphest Tasks: T104216
Removing all OSL script nodes from the shader graph would cause that
graph to no longer report it using `KERNEL_FEATURE_SHADER_RAYTRACE`
via `ShaderManager::get_graph_kernel_features`, but the shader object
itself still would have the `has_surface_raytrace` field set.
This caused kernels to be reloaded without shader raytracing support, but
later the `DEVICE_KERNEL_INTEGRATOR_SHADE_SURFACE_RAYTRACE`
kernel would still be invoked since the shader continued to report it
requiring that through the `SD_HAS_RAYTRACE` flag set because of
`has_surface_raytrace`.
Fix that by ensuring `has_surface_raytrace` is reset on every shader update,
so that when all OSL script nodes are deleted it is set to false, and only
stays true when there are still OSL script nodes (or other nodes using it).
Maniphest Tasks: T104157
Differential Revision: https://developer.blender.org/D17140
The background evaluation samples the sky discretely, so if the sun is
too small, it can be missed in the evaluation. To solve this, the sun is
ignored during the background evaluation and its contribution is
computed separately.
The lookup table method on CPU and the numerical root finding method on
GPU give quite different results. This commit deletes the Beckmann lookup
table and uses numerical root finding on all devices. For the numerical
root finding, a combined bisection-Newton method with precision control
is used.
Differential Revision: https://developer.blender.org/D17050
This makes it possible to use `texture` and `texture3d` in custom
OSL shaders with a constant image file name as argument on the
GPU, where previously texturing was only possible through Cycles
nodes.
For constant file name arguments, OSL calls
`OSL::RendererServices::get_texture_handle()` with the file name
string to convert it into an opaque handle for use on the GPU.
That is now used to load the respective image file using the Cycles
image manager and generate a SVM handle that can be used on
the GPU. Some care is necessary as the renderer services class is
shared across multiple Cycles instances, whereas the Cycles image
manager is local to each.
Maniphest Tasks: T101222
Differential Revision: https://developer.blender.org/D17032
The problem here is that whether an object is a shadow catcher or not affects the
visibility flags, but changes to the shadow catcher property did not trigger a
visibility flag update.
When rendering in the viewport (or probably on instanced objects, but I didn't
test that), emissive objects whose scale is negative give the wrong value on the
"backfacing" input when multiple sampling is enabled.
The underlying problem was a corner case in how normal transformation is handled,
which is generally a bit messy.
From what I can tell, the pattern appears to be:
- If you first transform vertices to world space and then compute the normal from
them (as triangle light samping, MNEE and light tree do), you need to flip
whenever the transform has negative scale regardless of whether the transform
has been applied
- If you compute the normal in object space and then transform it to world space
(as the regular shader_setup_from_ray path does), you only need to flip if the
transform was already applied and was negative
- If you get the normal from a local intersection result (as bevel and SSS do),
you only need to flip if the transform was already applied and was negative
- If you get the normal from vertex normals, you don't need to do anything since
the host-side code does the flip for you (arguably it'd be more consistent to
do this in the kernel as well, but meh, not worth the potential slowdown)
So, this patch fixes the logic in the triangle emission code.
Also, turns out that the MNEE code had the same problem and was also having
problems in the viewport on negative-scale objects, this is also fixed now.
Differential Revision: https://developer.blender.org/D16952
The code that computes and inverts the shutter CDF had some issues that caused
the result to be asymmetric, this tweaks it to be more robust and produce
symmetric outputs for symmetric inputs.
To better estimate light contribution. Note that estimating the texture
from the IES file is still missing.
Contributed by Alaska.
Differential Revision: https://developer.blender.org/D16901
Expands Color Mix nodes with new Exclusion mode.
Similar to Difference but produces less contrast.
Requested by Pierre Schiller @3D_director and
@OmarSquircleArt on twitter.
Differential Revision: https://developer.blender.org/D16543
This adds a new mirror image extension type for shaders and
geometry nodes (next to the existing repeat, extend and clip
options).
See D16432 for a more detailed explanation of `wrap_mirror`.
This also adds a new sampler flag `GPU_SAMPLER_MIRROR_REPEAT`.
It acts as a modifier to `GPU_SAMPLER_REPEAT`, so any `REPEAT`
flag must be set for the `MIRROR` flag to have an effect.
Differential Revision: https://developer.blender.org/D16432
This is done based on the render sample count so that it doesn't impact
sampling quality. It's similar in spirit to the adaptive table size in D16561,
but in this case for performance rather than memory usage.
Differential Revision: https://developer.blender.org/D16726
The first two dimensions of scrambled, shuffled Sobol and shuffled PMJ02 are
equivalent, so this makes no real difference for the first two dimensions.
But Sobol allows us to naturally extend to more dimensions.
Pretabulated Sobol is now always used, and the sampling pattern settings is now
only available as a debug option.
This in turn allows the following two things (also implemented):
* Use proper 3D samples for combined lens + motion blur sampling. This
notably reduces the noise on objects that are simultaneously out-of-focus
and motion blurred.
* Use proper 3D samples for combined light selection + light sampling.
Cycles was already doing something clever here with 2D samples, but using
3D samples is more straightforward and avoids overloading one of the
dimensions.
In the future this will also allow for proper sampling of e.g. volumetric
light sources and other things that may need three or four dimensions.
Differential Revision: https://developer.blender.org/D16443
There has been an attempt to reorganize this part, however, it seems that didn't compile on HIP, and is reverted in
rBc2dc65dfa4ae60fa5d2c3b0cfe86f99dcb5bf16f. This is another attempt of refactoring. as I have no idea why some things don't work on HIP, it's
best to check whether this compiles on other platforms.
The main changes are creating a new struct named `MeshLight` that is shared between `KernelLightDistribution` and `KernelLightTreeEmitter`,
and a bit of renaming, so that light sampling with or without light tree could call the same function.
Also, I noticed a patch D16714 referring to HIP compilation error. Not sure if it's related, but browsing
https://builder.blender.org/admin/#/builders/30/builds/7826/steps/7/logs/stdio, it didn't work on gfx1102, not gfx9*.
Differential Revision: https://developer.blender.org/D16722
To avoid issues with lights being either skipped or sampled unnecessarily
when the exposure is set low or high.
Contributed by Alaska.
Differential Revision: https://developer.blender.org/D16703
* preempt_attr was copied from CUDA, but not used in HIP.
* Remove shadowed variable before conditional in EnvironmentTextureNode code.
Differential Revision: https://developer.blender.org/D16741
**Problem**:
Area lights in Cycles have spread angle, in which case some part of the area light might be invisible to a shading point. The current implementation samples the whole area light, resulting some samples invisible and thus simply discarded. A technique is applied on rectangular light to sample a subset of the area light that is potentially visible (rB3f24cfb9582e1c826406301d37808df7ca6aa64c), however, ellipse (including disk) area lights remained untreated. The purpose of this patch is to apply a techniques to ellipse area light.
**Related Task**:
T87053
**Results**:
These are renderings before and after the patch:
|16spp|Disk light|Ellipse light|Square light (for reference, no changes)
|Before|{F13996789}|{F13996788}|{F13996822}
|After|{F13996759}|{F13996787}|{F13996852}
**Explanation**:
The visible region on an area light is found by drawing a cone from the shading point to the plane where the area light lies, with the aperture of the cone being the light spread.
{F13990078,height=200}
Ideally, we would like to draw samples only from the intersection of the area light and the projection of the cone onto the plane (forming a circle). However, the shape of the intersection is often irregular and thus hard to sample from directly.
{F13990104,height=200}
Instead, the current implementation draws samples from the bounding rectangle of the intersection. In this case, we still end up with some invalid samples outside of the circle, but already much less than sampling the original area light, and the bounding rectangle is easy to sample from.
{F13990125}
The above technique is only applied to rectangle area lights, ellipse area light still suffers from poor sampling. We could apply a similar technique to ellipse area lights, that is, find the
smallest regular shape (rectangle, circle, or ellipse) that covers the intersection (or maybe not the smallest but easy to compute).
For disk area light, we consider the relative position of both circles. Denoting `dist` as the distance between the centre of two circles, and `r1`, `r2` their radii. If `dist > r1 + r2`, the area light is completely invisible, we directly return `false`. If `dist < abs(r1 - r2)`, the smaller circle lies inside the larger one, and we sample whichever circle is smaller. Otherwise, the two circles intersect, we compute the bounding rectangle of the intersection, in which case `axis_u`, `len_u`, `axis_v`, `len_v` needs to be computed anew. Depending on the distance between the two circles, `len_v` is either the diameter of the smaller circle or the length of the common chord.
|{F13990211,height=195}|{F13990225,height=195}|{F13990274,height=195}|{F13990210,height=195}
|`dist > r1 + r2`|`dist < abs(r1 - r2)`|`dist^2 < abs(r1^2 - r2^2)`|`dist^2 > abs(r1^2 - r2^2)`
For ellipse area light, it's hard to find the smallest bounding shape of the intersection, therefore, we compute the bounding rectangle of the ellipse itself, then treat it as a rectangle light.
|{F13990386,height=195}|{F13990385,height=195}|{F13990387,height=195}
We also check the areas of the bounding rectangle of the intersection, the ellipse (disk) light, and the spread circle, then draw samples from the smallest shape of the three. For ellipse light, this also detects where one shape lies inside the other. I am not sure if we should add this measure to rectangle area light and sample from the spread circle when it has smaller area, as we seem to have a better sampling technique for rectangular (uniformly sample the solid angle). Maybe we could add [area-preserving parameterization for spherical
ellipse](https://arxiv.org/pdf/1805.09048.pdf) in the future.
**Limitation**:
At some point we switch from sampling the ellipse to sampling the rectangle, depending on the area of the both, and there seems to be a visible line (with |slope| =1) on the final rendering
which demonstrate at which point we switch between the two methods. We could see that the new sampling method clearly has lower variance near the boundaries, but close to that visible line,
the rectangle sampling method seems to have larger variance. I could not spot any bug in the implementation, and I am not sure if this happens because different sampling patterns for ellipse and rectangle are used.
|Before (256spp)|After (256spp)
|{F13996995}|{F13996998}
Differential Revision: https://developer.blender.org/D16694
Uses a light tree to more effectively sample scenes with many lights. This can
significantly reduce noise, at the cost of a somewhat longer render time per
sample.
Light tree sampling is enabled by default. It can be disabled in the Sampling >
Lights panel. Scenes using light clamping or ray visibility tricks may render
different as these are biased techniques that depend on the sampling strategy.
The implementation is currently disabled on AMD HIP. This is planned to be fixed
before the release.
Implementation by Jeffrey Liu, Weizhen Huang, Alaska and Brecht Van Lommel.
Ref T77889
This was not working well in non-trivial scenes before the light tree, and now
it is even harder to make it work well with the light tree. It would average the
with equal weight for every light object regardless of intensity or distance, and
be quite noisy due to not working with multiple importance sampling.
We may restore this if were enough good use cases for the previous implementation,
but let's wait and see what the feedback is.
Some uses cases for this have been replaced by the shadow catcher passes, which
did not exist when this was added.
Ref T77889
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
* Split light types into own files, move light type specific code from
light tree and MNEE.
* Move flat light distribution code into own kernel file and host side
building function, in preparation of light tree addition. Add light/sample.h
as main entry point to kernel light sampling.
* Better separate calculation of pdf for selecting a light, and pdf for
sampling a point on the light. The selection pdf is now also stored in
LightSampling for MNEE to correctly recalculate the full pdf when the
shading position changes but the point on the light remains fixed.
* Improvement to kernel light storage, using packed_float3, better variable
names, etc.
Includes contributions by Brecht Van Lommel and Weizhen Huang.
Ref T77889
When either initializing with a non-constant value, or using the standard
[[ string widget = "null" ]] metadata. This can be used for inputs like
normals and texture coordinates, where you don't want to default to a
constant value.
In previous OSL versions the input value was automatically ignore when it
was left unchanged for such inputs. However that's no longer the case in
the latest version, breaking existing nodes. There is no good entirely
backwards compatible fix, but I believe the new behavior is better and will
keep most existing cases working.
Fix T102450: OSL node with normal input not working
It is possible that the image editor redraw happens prior to the
"Loading render kernels" status is reported from status but after
the display driver is created. This will make the image editor to
wait on the scene mutex to update the display pass in the film.
If it happens to be that the kernels are actually to be compiled
then the Blender interface appears to be completely frozen, without
any information line in the image editor.
This change makes it so the amount of time the scene mutex is held
during the kernel compilation is minimal.
It is a bit unideal to unlock and re-lock the scene mutex in the
middle of update, while nested reset mutex is held, but this is
already what is needed for the OptiX denoiser optimization some
lines below. We can probably reduce the lifetime of some locks,
avoiding such potential out-of-order re-locking. Doing so is
outside of the scope of this patch.
The scene update only happens from the single place in the session,
which makes it easy to ensure the kernels are loaded prior the rest
of the scene update.
Not only this change makes it so that the "Loading render kernels"
status appears in the image editor, but also allows to pan and zoom
in the image editor, potentially allowing artists to re-adjust their
point of interest.
Differential Revision: https://developer.blender.org/D16581
This resolves some issues with correlation artifacts at higher sample counts.
Fix T101356, correlation issues in new PMJ pattern.
Differential Revision: https://developer.blender.org/D16561
Commit c8dd33f5a37b6a6db0b6950d24f9a7cff5ceb799 in OSL changed behavior of
parameters that reference each other and are also overwritten with an
instance value. This is causing the "NormalIn" parameter of a few OSL nodes
in Cycles to be set to zero somehow, which should instead have received the
value from a "node_geometry" node Cycles generates and connects automatically.
I am not entirely sure why that is happening, but these parameters are
superfluous anyway, since OSL already provides the necessary data in the
global variable "N". So this patch simply removes those parameters (which
mimics SVM, where these parameters do not exist either), which also fixes
the rendering artifacts that occured with recent OSL.
While this fixes built-in shader nodes, custom OSL scripts can still have
this problem.
Ref T101222
Differential Revision: https://developer.blender.org/D16470
