Doesn't currently change anything, but would need for some future
work here.
It uses existing padding in kernel BVH structure, so there is
nothing changed memory-wise.
The issue here was mainly coming from minimal pixel width feature
which is quite commonly enabled in production shots.
This feature will use some probabilistic heuristic in the curve
intersection function to check whether we need to return intersection
or not. This probability is calculated for every intersection check.
Now, when we use multiple BVH nodes for curve primitives we increase
probability of that primitive to be considered a good intersection
for us. This is similar to increasing minimal width of curve.
What is worst here is that change in the intersection probability
fully depends on exact layout of BVH, meaning probability might
change differently depending on a view angle, the way how builder
binned the primitives and such. This makes it impossible to do
simple check like dividing probability by number of BVH steps.
Other solution might have been to split BVH into fully independent
trees, but that will increase memory usage of all the static
objects in the scenes, which is also not something desirable.
For now used most simple but robust approach: store BVH primitives
time and test it in curve intersection functions. This solves the
regression, but has two downsides:
- Uses more memory.
which isn't surprising, and ANY solution to this problem will
use more memory.
What we still have to do is to avoid this memory increase for
cases when we don't use BVH motion steps.
- Reduces number of maximum available textures on pre-kepler cards.
There is not much we can do here, hardware gets old but we need
to move forward on more modern hardware..
Seems CUDA failed to de-duplicate the array across multiple inlined
versions of the shadow_blocked(). Helped it a bit with that now.
Gives about 100MB memory improvement on a scenes after previous
commit and brings up memory "regression" to only 100MB comparing to
the master branch now.
This commit enables record-all behavior of transparent shadows
rays.
Render times difference goes as following:
GTX 1080 render time
BMW -0.5%
Fishy Cat -0.0%
Pabellon Barcelona -11.6%
Classroom +1.2%
Koro -58.6%
Kernel will now use some extra VRAM memory to store the intersection
array (200MB on my configuration). This we can optimize out with some
further commits.
The idea is to record all possible transparent intersections when
shooting transparent ray on GPU (similar to what we were doing on
CPU already).
This avoids need of doing whole ray-to-scene intersections queries
for each intersection and speeds up a lot cases like transparent
hair in the cost of extra memory.
This commit is a base ground for now and this feature is kept
disabled for until some further tweaks.
Now we break the traversal cycle and then perform volume attenuation
and check with zero throughput. Not sure it makes any measurable sense
at this moment, but in the future it might help de-duplicating some
extra logic here.
This is a speed up option which is mainly useful for viewport. Gives nice speedup in
the barbershop scene of 2x when replacing GI with AO after 2nd bounce without loosing
too much details.
Reviewers: brecht
Subscribers: eyecandy, venomgfx
Differential Revision: https://developer.blender.org/D2383
We started to run out of bits there, so now we separate flags
which came from __object_flags and which are either runtime or
coming from __shader_flags.
Rule now is: SD_OBJECT_* flags are to be tested against new
object_flags field of ShaderData, all the rest flags are to
be tested against flags field of ShaderData.
There should be no user-visible changes, and time difference
should be minimal. In fact, from tests here can only see hardly
measurable difference and sometimes the new code is somewhat
faster (all within a noise floor, so hard to tell for sure).
Reviewers: brecht, dingto, juicyfruit, lukasstockner97, maiself
Differential Revision: https://developer.blender.org/D2428
This way we can stop traversing BVH node early on.
Gives about 2-2.5x times render time improvement with 3 BVH steps.
Hopefully this gives no measurable performance loss for scenes with
single BVH step.
Traversal is currently only implemented for QBVH, meaning old CPUs
and GPU do not benefit from this change.
Mimics how regular triangles are working and makes it more clear where
the stuff is located in the kernel.
Needed to have some forward declarations because of the current placement
of things in the kernel.
Was a bit confusing to have transparent and translucent depth
exposed but no diffuse or glossy.
Reviewers: brecht
Subscribers: eyecandy
Differential Revision: https://developer.blender.org/D2399
This matches behavior of Multiscatter GGX and could become handy later on
when/if we decide it would be beneficial to replace on closure with another.
Reviewers: lukasstockner97, brecht
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D2413
There was 16 bits reserved for primitive type, while we only need 4.
Reviewers: brecht
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D2401
Discard the whole volume stack on the last bounce (but keep
world volume if present).
Volumes are expected to be closed manifol meshes, meaning if
ray entered the volume there should be an intersection event
of ray exisintg the volume. Case when ray hit nothing and
there are still non-world volumes in the stack can happen in
either of cases.
1. Mesh is not closed manifold.
Such configurations are not really supported anyway and should
not be used.
Previous code would have consider the infinite length of the
ray to sample across, so render result wasn't really correct
anyway.
2. Exit intersection is more far away than the camera far
clip distance.
This case also will behave differently now, but previously it
wasn't really correct either, so it's not like we're breaking
something which was working as expected.
3. We missed exit event due to intersection precision issues.
This is exact the case which this patch fixes and avoid
fireflies.
4. Volume has Camera only visibility (all the rest visibility
is set to off)
This is what could be considered a regression but could be
solved quite easily by checking volume stack's objects flags
and keep entries which doesn't have Volume Scatter visibility
(or even better: ensure Volume Scatter visibility for objects
with volume closure),
Fixes T46108: Cycles - Overlapping emissive volumes generates unexpected bright hotspots around the intersection
Also fixes fireflies appearing on the edges of cube with
emissive volue.
Reviewers: juicyfruit, brecht
Reviewed By: brecht
Maniphest Tasks: T46108
Differential Revision: https://developer.blender.org/D2212
There were two cases where correlation issues were obvious:
- File from T38710 was giving issues in 2.78a again
- File from T50116 was having totally different shadow between
sample 1 and sample 32.
Use some more simplified version of CMJ hash which seems to give
nice randomized value which solves the correlation.
This commit will break all unit test files, but it's a bug fix
so perhaps OK to commit this.
This also fixes T41143: Sobol gives nonuniform noise
Proper science paper about hash function is coming.
Reviewers: brecht
Reviewed By: brecht
Subscribers: lukasstockner97
Differential Revision: https://developer.blender.org/D2385
Was giving huge artifacts in the barber shop file here in the studio,
Maybe not fully optimal solution, but committing it for now to have
closer look later.
`kernel_path.h` and `kernel_path_branched.h` have a lot of conditional code and
it was kind of hard to tell what code belonged to which directive. Should be
easier to read now.
Basically, the problem here was that the transform that's used to bring texture coordinates
to world space is either fetched while setting up the shader (with Object Motion is enabled) or
fetched when needed (otherwise). That helps to save ShaderData memory on OpenCL when Object Motion isn't needed.
Now, if OM is enabled, the Lamp transform can just be stored inside the ShaderData as well. The original commit just assumed it is.
However, when it's not (on OpenCL by default, for example), there is no easy way to fetch it when needed, since the ShaderData doesn't
store the Lamp index.
So, for now the lamps just don't support local texture coordinates anymore when Object Motion is disabled.
To fix and support this properly, one of the following could be done:
- Just always pre-fetch the transform. Downside: Memory Usage increases when not using OM on OpenCL
- Add a variable to ShaderData that stores the Lamp ID to allow fetching it when needed
- Store the Lamp ID inside prim or object. Problem: Cycles currently checks these for whether an object was hit - these checks would need to be changed.
- Enable OM whenever a Texture Coordinate's Normal output is used. Downside: Might not actually be needed.
This allows to save a memory copy, which will be particularly useful for network rendering.
Reviewers: sergey, brecht, dingto, juicyfruit, maiself
Differential Revision: https://developer.blender.org/D2323
In scenes with many lights, some of them might have a very small contribution to some pixels, but the shadow rays are traced anyways.
To avoid that, this patch adds probabilistic termination to light samples - if the contribution before checking for shadowing is below a user-defined threshold, the sample will be discarded with probability (1 - (contribution / threshold)) and otherwise kept, but weighted more to remain unbiased.
This is the same approach that's also used in path termination based on length.
Note that the rendering remains unbiased with this option, it just adds a bit of noise - but if the setting is used moderately, the speedup gained easily outweighs the additional noise.
Reviewers: #cycles
Subscribers: sergey, brecht
Differential Revision: https://developer.blender.org/D2217
This option allows to create a smoother transition between Bricks and Mortar - 0 applies no smoothing, and 1 smooths across the whole mortar width.
Mainly useful for displacement textures.
The new default value for the smoothing option is 0.1 to give some smoothing that helps with antialiasing, but existing nodes are loaded with smoothing 0 to preserve compatibility.
Reviewers: sergey, dingto, juicyfruit, brecht
Reviewed By: brecht
Subscribers: Blendify, nutel
Differential Revision: https://developer.blender.org/D2230
