These latter can cause MSVC debug asserts if the array is empty. With C++11
we'll be able to do this for std::vector later. This hopefully fixes an assert
in the Cycles subdivision code.
By calling `tessellate()` from the mesh manager in Cycles we can do pre/post
processing or even threaded tessellation without concerning client side code
with the details.
Displacement is now a per material setting, which means old files will have to
be updated if they had used displacement. Cool side effect of this change is
material previews now show displacement.
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D2140
Enables Catmull-Clark subdivision meshes with support for creases and attribute
subdivision. Still waiting on OpenSubdiv to fully support face varying
interpolation for subdividing uv coordinates tho. Also there may be some
inconsistencies with Blender's subdivision which will be resolved at a
later time.
Code for reading patch tables and creating patch maps is borrowed
from OpenSubdiv.
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D2111
Adds a descriptor for attributes that can easily be passed around and extended
to contain more data. Will be used for attributes on subdivision meshes.
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D2110
Subdivision options can now be found in the subsurf modifier. The modifier must
be the last in the stack or the options will be unavailable. Catmull-Clark
subdivision is still unavailable and will fallback to linear subdivision instead
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D2109
This adds support for ngons and attributes on subdivision meshes. Ngons are
needed for proper attribute interpolation as well as correct Catmull-Clark
subdivision. Several changes are made to achieve this:
- new primitive `SubdFace` added to `Mesh`
- 3 more textures are used to store info on patches from subd meshes
- Blender export uses loop interface instead of tessface for subd meshes
- `Attribute` class is updated with a simplified way to pass primitive counts
around and to support ngons.
- extra points for ngons are generated for O(1) attribute interpolation
- curves are temporally disabled on subd meshes to avoid various bugs with
implementation
- old unneeded code is removed from `subd/`
- various fixes and improvements
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D2108
This is a bit weak, but better than tagging whole mesh manager for update.
Maybe we'll solve such dual-look up in the future.
This commit finally solves T48963: Noise when changing Diffuse node to Emission node
While it's an extra option added to the interface which might not be
fully obvious for artists, it allows to save up to 20% of memory in
hairy scenes.
This is high enough memory saver in my opinion which might become
handy for some production files where it's more important to make
scene to fit into memory rather than trying to use more optimal BVH
structure but go into swap or crash.
Reviewers: dingto, brecht
Reviewed By: dingto, brecht
Differential Revision: https://developer.blender.org/D2090
This commit enables new unaligned BVH builder and traversal for scenes
with hair. This happens automatically, no need of manual control over
this.
There are some possible optimization still to happen here and there,
but overall there's already nice speedup:
Master Hair BVH
bunny.blend 8:06.54 5:57.14
victor.blend 16:07.44 15:37.35
Unfortunately, such more complexity is not really coming for free,
so there's some downsides, but those are within acceptable range:
Master Hair BVH
classroom.blend 5:31.79 5:35.11
barcelona.blend 4:38.58 4:44.51
Memory usage is also somewhat bigger for hairy scenes, but speed
benefit pays well for that. Additionally as was mentioned in one
of previous commits we can add an option to disable hair BVH and
have similar render time but have memory saving.
Reviewers: brecht, dingto, lukasstockner97, juicyfruit, maiself
Differential Revision: https://developer.blender.org/D2086
This is a special builder type which is allowed to orient nodes to
strands direction, hence minimizing their surface area in comparison
with axis-aligned nodes. Such nodes are much more efficient for hair
rendering.
Implementation of BVH builder is based on Embree, and generally idea
there is to calculate axis-aligned SAH and oriented SAH and if SAH
of oriented node is smaller than axis-aligned SAH we create unaligned
node.
We store both aligned and unaligned nodes in the same tree (which
seems to be different from what Embree is doing) so we don't have
any any extra calculations needed to set up hair ray for BVH
traversal, hence avoiding any possible negative effect of this new
BVH nodes type.
This new builder is currently not in use, still need to make BVH
traversal code aware of unaligned nodes.
There are several internal changes for this:
First idea is to make __tri_verts to behave similar to __tri_storage,
meaning, __tri_verts array now contains all vertices of all triangles
instead of just mesh vertices. This saves some lookup when reading
triangle coordinates in functions like triangle_normal().
In order to make it efficient needed to store global triangle offset
somewhere. So no __tri_vindex.w contains a global triangle index which
can be used to read triangle vertices.
Additionally, the order of vertices in that array is aligned with
primitives from BVH. This is needed to keep cache as much coherent as
possible for BVH traversal. This causes some extra tricks needed to
fill the array in and deal with True Displacement but those trickery
is fully required to prevent noticeable slowdown.
Next idea was to use this __tri_verts instead of __tri_storage in
intersection code. Unfortunately, this is quite tricky to do without
noticeable speed loss. Mainly this loss is caused by extra lookup
happening to access vertex coordinate.
Fortunately, tricks here and there (i,e, some types changes to avoid
casts which are not really coming for free) reduces those losses to
an acceptable level. So now they are within couple of percent only,
On a positive site we've achieved:
- Few percent of memory save with triangle-only scenes. Actual save
in this case is close to size of all vertices.
On a more fine-subdivided scenes this benefit might become more
obvious.
- Huge memory save of hairy scenes. For example, on koro.blend
there is about 20% memory save. Similar figure for bunny.blend.
This memory save was the main goal of this commit to move forward
with Hair BVH which required more memory per BVH node. So while
this sounds exciting, this memory optimization will become invisible
by upcoming Hair BVH work.
But again on a positive side, we can add an option to NOT use Hair
BVH and then we'll have same-ish render times as we've got currently
but will have this 20% memory benefit on hairy scenes.
- add_vertex() can be called from split_vertex() which does not guarantee
to have properly pre-allocate arrays.
- Need to check whether Cycles is compiled with OSL in XML reader.
This fixes a rare case where NaNs could exist inside Cycles.
When certain invalid meshes were passed in, Cycles would try too normalize
a zero length normal during its setup stage. While it does check against
division by zero, it still returns a zero length normal and passes it on to
the path tracing kernel. The kernel then operates under the assumption that
normals are valid, and in the case of such a zero length normal, would
eventually create NaNs that propagate through and result in black pixels.
Reviewers: #cycles
Subscribers: brecht, sergey
Projects: #cycles
Differential Revision: https://developer.blender.org/D2008
Mainly makes logging less verbose when doing progressive sampling in viewport.
Such kind of verbosity is not really possible to be filtered out with `grep`
so let's reshuffle few lines of code.
This is an attempt to gracefully handle out-of-memory events
and stop rendering with an error message instead of a crash.
It uses bad_alloc exception, and usually i'm not really fond
of exceptions, but for such limited use for errors from which
we can't recover it should be fine.
Ideally we'll need to stop full Cycles Session, so viewport
render and persistent images frees all the memory, but that
we can support later, since it'll mainly related on telling
Blender what to do.
General rules are:
- Use as less exception handles as possible, try to find a
most geenric pace where to handle those.
For example, ccl::Session.
- Threads needs own handling, exception trap from one thread
will not catch exceptions from other threads.
That's why BVH build needs own thing.
Reviewers: brecht, juicyfruit, dingto, lukasstockner97
Differential Revision: https://developer.blender.org/D1898
This way we prevent cracks in the model due to discontinuous normals, by using
smooth normals for displacement instead of always getting flat normals after
linear subdivision.
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D1916
We had per-tree statistics already, but it's a bit tricky to see overall
time because trees could be building in parallel.
In fact, we can now print statistics for any TaskPool.
This commit makes it so casting subsurface rays will totally ignore all
the BVH nodes and primitives which do not belong to a current object,
making it much simpler traversal code and reduces number of intersection
tests.
Reviewers: brecht, juicyfruit, dingto, lukasstockner97
Differential Revision: https://developer.blender.org/D1823
Notes:
- There is still some bvh cache code, but that is from the engines initial commit, we might clean this up further or keep it.
- Changes in util_cache.h/.c are kept, this might be re-used in the future.
The issue was caused by the reshuffle needed to make objects flags have proper
object's bounding box to solve regressions in SSS objects intersecting volumes.
There's actually a feedback loop happening here, which is now solved in quite
naive way -- for the true displacement we consider all objects are capable of
intersecting volumes, synchronize object flags prior to displacement shader
tasks runs and then re-update object flags for proper bounding box.
Not sure what will be the proper solution here, we can't do preliminary check
of intersection for displacement shader, but on the other hand we don't really
need this flag for displacement shader anyway.
This way we can get rid of inefficient memory usage caused by BVH boundbox
part being unused by leaf nodes but still being allocated for them. Doing
such split allows to save 6 of float4 values for QBVH per leaf node and 3
of float4 values for regular BVH per leaf node.
This translates into following memory save using 01.01.01.G rendered
without hair:
Device memory size Device memory peak Global memory peak
Before the patch: 4957 5051 7668
With the patch: 4467 4562 7332
The measurements are done against current master. Still need to run speed tests
and it's hard to predict if it's faster or not: on the one hand leaf nodes are
now much more coherent in cache, on the other hand they're not so much coherent
with regular nodes anymore.
Reviewers: brecht, juicyfruit
Subscribers: venomgfx, eyecandy
Differential Revision: https://developer.blender.org/D1236
This way memory overhead caused by the BVH building is not so visible and peak
memory usage will be reduced.
Implementing this idea is not so straightforward actually, because we need to
synchronize images used for true displacement before meshes. Detecting whether
image is used for true displacement is not so striaghtforward, so for now all
all displacement types will synchronize images used for them.
Such change brings memory usage from 4.1G to 4.0G with the 01_01_01_D scene
from gooseberry. With 01_01_01_G scene it's 7.6G vs. 6.8G (before and after
the patch).
Reviewers: campbellbarton, juicyfruit, brecht
Subscribers: eyecandy
Differential Revision: https://developer.blender.org/D1217
This inconsistency drove me totally crazy, it's really confusing
when it's inconsistent especially when you work on both Cycles and
Blender sides.
Shouldn;t cause merge PITA, it's whitespace changes only, Git should
be able to merge it nicely.
The workaround for generated texture coordinates is to be done before
calculating number of elements for attribute, otherwise counter wouldn't
include those attributes.
The idea behind the change is to pre-allocate attribute arrays in advance,
which avoids re-allocation of arrays later for each of meshes being handled.
This reduces peak memory used by Cycles database from 1.3G to 0.9G for
victor.blend from Gooseberry.
It doesn't mean every file will benefit from this change since peak memory
usage is happening in the different places of the rendering code.
Also, unfortunately, attributes export might not cause the peak of render
preparation stage. That said, it's actually object_to_mesh() which causes
the memory to peak in the same test file. So we really need to optimize that
part first in order to get visible results for artists. But in any case it's
now quite easy to track hotspots in Cycles itself which is good.
This way we save 3 bytes per BVH node while building BVH, which overall
gives 100Mb memory save when preparing Frank for render.
It's not really much comparing to overall memory usage (which is 11Gb
during scene preparation here) but still doesn't harm to have solved.
Issue was caused by wrong order of scene device update, which could
lead to missing object flags in shader kernel.
This patch solves a bit more than that making sure objects flags are
always properly updated, so adding/removing volume BSDF will properly
reflect on viewport where camera might become being in volume and so.
This commit enables QBVH optimization structure automatically if rendering
with CPU and SSE2 support is detected.
This brings render time of agent shot back to the speed it used to be before
the watertight intersections commit, single koro and sponza scenes are about
7% faster here.
This commit implements traversal for QBVH tree, which is based on the old loop
code for traversal itself and Embree for node intersection.
This commit also does some changes to the loop inspired by Embree:
- Visibility flags are only checked for primitives.
Doing visibility check for every node cost quite reasonable amount of time
and in most cases those checks are true-positive.
Other idea here would be to do visibility checks for leaf nodes only, but
this would need to be investigated further.
- For minimum hair width we extend all the nodes' bounding boxes.
Again doing curve visibility check is quite costly for each of the nodes and
those checks returns truth for most of the hierarchy anyway.
There are number of possible optimization still, but current state is good
enough in terms it makes rendering faster a little bit after recent watertight
commit.
Currently QBVH is only implemented for CPU with SSE2 support at least. All
other devices would need to be supported later (if that'd make sense from
performance point of view).
The code is enabled for compilation in kernel. but blender wouldn't use it
still.
