Before the visibility test against the visibility flags was performed in an any-hit program in OptiX
(called `__anyhit__kernel_optix_visibility_test`), which was using the `__prim_visibility` array.
This is not entirely correct however, since `__prim_visibility` is filled with the merged visibility
flags of all objects that reference that primitive, so if one object uses different visibility flags
than another object, but they both are instances of the same geometry, they would appear the same
way. The reason that the any-hit program was used rather than the OptiX instance visibility mask is
that the latter is currently limited to 8 bits only, which is not sufficient to contain all Cycles
visibility flags (12 bits).
To mostly fix the problem with multiple instances and different visibility flags, I changed things to
use the OptiX instance visibility mask for a subset of the Cycles visibility flags (`PATH_RAY_CAMERA`
to `PATH_RAY_VOLUME_SCATTER`, which fit into 8 bits) and only fall back to the visibility test any-hit
program if that isn't enough (e.g. the ray visibility mask exceeds 8 bits or when using the built-in
curves from OptiX, since the any-hit program is then also used to skip the curve endcaps).
This may also improve performance in some cases, since by default OptiX can now perform the normal
scene intersection trace calls entirely on RT cores without having to jump back to the SM on every
hit to execute the any-hit program.
Fixes T89801
Differential Revision: https://developer.blender.org/D12604
Fix T91632: Stops the sample correlation between dimensions which was causing rendering artefacts on simple scenes.
This is done by increasing the amount of jitter the Cranley Patterson Rotation is allowed to add. Also, it uses the y dimension of the of the sample table for 1D sampling which causes further decorrelation between dimensions. As an additional measure the x and y dimensions are swapped randomly to provide further decorrelation.
Maniphest Tasks: T91632
Differential Revision: https://developer.blender.org/D12610
Goal is to add the length attribute to the Hair Info node, for better control over color gradients or similar along the hair.
Reviewed By: #eevee_viewport, brecht
Differential Revision: https://developer.blender.org/D10481
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
Prior to rBb8ecdbcd964a normals were stored both in
DeviceScene.tri_vnormal and the float3 attributes buffer. However, the
normals in `DeviceScene.tri_vnormal` might have be transformed to world
space if the object's transformation was applied, while the data in the
float3 attributes buffer were not. This caused shading issues in cases
where the objects did have transformation applied, as the math expects
the normals to be in object space.
To fix this, convert the normals to object space if necessary before
applying the normal map.
Reviewed By: brecht
Maniphest Tasks: T90854
Differential Revision: https://developer.blender.org/D12294
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
This modifies the attribute lookup to use object coordinates if no
generated coordinates are found on the geometry.
This is useful to avoid creating and copying this attribute, thus saving
a bit of time and memory.
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D12238
Vertex normals are needed for normals maps and therefore are packed and send
to the device alongside the other float3 attributes. However, we already pack
and send vertex normals through `DeviceScene.tri_vnormal`.
This removes the packing of vertex normals from the attributes buffer, and
reuses `tri_vnormal` in the kernel for normals lookup for normal maps, which
reduces memory usage a bit, and speeds up device updates.
This also fixes potential missing normals updates following rB12a06292af86,
since the need for vertex normals for normals maps was overlooked.
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D12237
The goal: allow to easily use AO approximation in scenes which combines
both small and large scale objects.
The idea: use per-object AO distance which will allow to override world
settings. Instancer object will "propagate" its AO distance to all its
instances unless the instance defines own distance (this allows to
modify AO distance in the shot files, without requiring to modify props
used in the shots.
Available from the new Fats GI Approximation panel in object properties.
Differential Revision: https://developer.blender.org/D12112
WITH_CYCLES_DEBUG was used for rendering BVH debugging passes. But since we
mainly use Embree an OptiX now, this information is no longer important.
WITH_CYCLES_DEBUG_NAN will enable additional checks for NaNs and invalid values
in the kernel, for Cycles developers. Previously these asserts where enabled in
all debug builds, but this is too likely to crash Blender in scenes that render
fine regardless of the NaNs. So this is behind a CMake option now.
Fixes T90240
This fixes a performance regression on Ampere cards, on specific scenes like
classroom. For cycles-x there is little difference, but this is still helpful
for LTS releases, and we need to upgrade at some point anyway.
Custom properties defined on objects are not accessible from the
attribute node when rendering a volume in Cycles. This is because
this case is not handled.
To handle it, added a primitive type for volumes in the kernel,
which is then used in the initialization of ShaderData and to
check whether an attribute lookup is for a volume.
`volume_attribute_float4` is also now checking the attribute
element type to dispatch to the right lookup function.
Reviewed By: #cycles, brecht
Maniphest Tasks: T87194
Differential Revision: https://developer.blender.org/D11728
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
Cycles, Eevee, OSL, Geo, Attribute
This operator provides consistency with the standard math node. Allows users to use a single node instead of two nodes for this common operation.
Reviewed By: HooglyBoogly, brecht
Differential Revision: https://developer.blender.org/D10808
Both before and after can have artifacts with some normal maps, but this seems to give
worse artifacts on average which are not worth the minor performance increase.
This reverts commit 21bc1a99ba.
Ref T88368, D10084
These seem to be causing some stability issues, and really are just not that
useful in practice. Compiling them is slow already, so it does not improve
the user experience much to show an AO preview if it's not nearly instant.
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
