Mainly the changes are related on establishing API to feed UV islands
to OpenSubdiv, so it will know all the connectivity information and
will be able to do proper interpolation.
Island calculation is currently rather slow, not sure how to make it
fast and not use lots of allocations.
Shouldn't be THAT bad, since this code is only runs once when creating
OSD mesh, and it's probably still faster than our orientation code.
A bit work in progress, currently the following limitations:
- Texture shading only, Material shading will come later
- No UVs subdivision yet
- Always uses active UV and currently changing active UV will
not properly update the viewport.
Well, need to start somewhere :)
This probably makes code somewhat slower, but we can't easily know
whether we can use a shortcut and only use directional lighting from
the scene.
Need some better integration between GPU and OpenSubdiv for that.
This patch addresses the following issues in bf_intern_ghost
```
Warning C4312 'type cast': conversion from 'GHOST_TEmbedderWindowID' to 'HWND' of greater size bf_intern_ghost K:\BlenderGit\blender\intern\ghost\intern\GHOST_WindowWin32.cpp 179
Warning C4312 'type cast': conversion from 'GHOST_TEmbedderWindowID' to 'HWND' of greater size bf_intern_ghost K:\BlenderGit\blender\intern\ghost\intern\GHOST_WindowWin32.cpp 198
```
GHOST_TEmbedderWindowID is defined as long, handles are however of pointer size,
so this should have been an issue when we moved to 64 bits, guess we got lucky.
fixed by turning GHOST_TEmbedderWindowID from long into void*
```
Warning C4302 'reinterpret_cast': truncation from 'HKL' to 'LANGID' bf_intern_ghost K:\BlenderGit\blender\intern\ghost\intern\GHOST_ImeWin32.cpp 67
```
reinterpret_cast emits warnings on truncation, LOWORD does the job just
as well with no warnings.
```
Warning C4838 conversion from 'int' to 'DWORD' requires a narrowing conversion bf_intern_ghost K:\BlenderGit\blender\intern\ghost\intern\GHOST_ContextWGL.cpp 734
Warning C4838 conversion from 'int' to 'BYTE' requires a narrowing conversion bf_intern_ghost K:\BlenderGit\blender\intern\ghost\intern\GHOST_ContextWGL.cpp 734
```
Weird warning, it does a really bad job at telling you what parameter is
causing the warning , tuns out there's a bunch of parameters that cause it
but it still only yields a single warning, the problem is that every
(somevar ? a : b) construct results in an integer type. which needs to be
properly cast to get rid of the warning.
```
Warning C4996 'GetVersionExA': was declared deprecated bf_intern_ghost K:\BlenderGit\blender\intern\ghost\intern\GHOST_WindowWin32.cpp 105
Warning C4996 'GetVersionExA': was declared deprecated bf_intern_ghost K:\BlenderGit\blender\intern\ghost\intern\GHOST_WindowWin32.cpp 107
```
The warning was clear, the code not as much. The version check in place
here is quite convoluted and could be replaced by including VersionHelpers.h
and calling IsWindows7OrGreater, However, CreateInstance will just return NULL
in m_Bar if the interface is not supported, so the whole check is useless.
This however did require that the CreateInstance call actually asked for
ITaskbarList3 and not ITaskBarlist . (You're not really allowed to assign
different interface types to each-other, a roundtrip through QueryInterface
is required there, we were violating spec here by asking for ITaskBarlist and
storing it in ITaskbarList3* )
Reviewers: sergey
Reviewed By: sergey
Subscribers: sergey
Differential Revision: https://developer.blender.org/D2094
The issue was caused by SSS intersection code gathering all
intersections without check for duplicated ones. This caused
situations when same intersection will be recorded twice in
the case if triangle is shared by several BVH nodes.
Usually this is handled by checking intersection distance
after sorting intersections (in shadow_blocked for example)
but for SSS we don't do such sorting and using number of
intersections to calculate various things.
Didn't find anything smarter than to check intersection
distance in triangle_intersect_subsurface().
This solves render artifacts in the cost of 1.5% slowdown
of extreme case rendering (SSS object filling in whole
FullHD screen).
Reviewers: brecht
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D2105
- In fresnel_dielectric, the differentials calculation sometimes divided by zero.
- When the normal map was (0.5, 0.5, 0.5), the code would try to normalize a zero vector. Now, it just uses the regular normal as a fallback.
- The approximate error function used in Beckmann sampling sometimes overflowed to inf while calculating r^16. The final value is 1 - 1/r^16, however,
so now it just returns 1 if the computation would overflow otherwise.
Also, this fixes a numerical issue where A would be inf.
Since later G is set to 1 if A is larger than 1.6, the code now checks the reciprocal of A for being smaller than 1/1.6 - same effect, but no inf involved.
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
After reformulation of SSS indirect rays it became possible to
try accessing dimension higher than was pre-calculated on scene
preparation.
This is because we're traversing rays backwards, which means we
are using higher dimensions first now.
It was possible to miss bounces termination criteria in this functions,
mainly when max_hits was set to 0.
Made the check more robust in traversal functions (which should not
affect performance, it's an operation of same complexity AFAIK).
Also avoid doing ray-scene intersection from shadow_blocked when
limit of transparent bounces was already reached.
This way restrict can be used for CUDA and OpenCL as well.
From quick tests in areas i've been testing this it might give some
barely measurable %% of speedup, but it increases registers pressure.
So use of this qualifier is still really limited.
Using camel case for variables is something what didn't came from our original
code, but rather from third party libraries. Let's avoid those as much as possible.
Matches better naming of volume traversal files, where we've got
optimized versions of a single step of volume intersection and
traversal which will gather all volume intersections.
BVH traversal is not really that much a geometry and we've got
quite some traversals now. Makes sense to keep them separate in
the name of source structure clarity.
The shader sync code used the anisotropic version of the Ashikhmin-Shirley closure for both
Anisotropic and Glossy BSDF, which caused a failed assert because the anisotropic closure
expects an addiitonal SVM node.
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 commit implements traversal of unaligned BVH nodes.
QBVH traversal is fully SIMD optimized and calculates orientation
for all 4 children at a time, regular BVH might probably be optimized
a bit more.
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.
This seems to be straightforward way to support heterogeneous nodes
in the same tree.
There is some penalty related on 4gig limit of the address space now,
but here's are the thing:
Traversal code was already using ints to store final offset, so
there can't be regressions really.
This is a required commit to make it possible to encode both aligned
and unaligned nodes in the same array. Also, in the future we can use
this to get rid of __leaf_nodes array (which is a bit tricky to do since
trickery in pack_instances().
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.
It was initially unsupported because initial idea of checking visibility
of all children was slowing scenes down a lot. Now the idea has changed
and we only perform visibility check of current node. This avoids huge
slowdown (from tests here it seems to be withing 1-2%, but more tests
would never hurt) and gives nice speedup of ray traversal for complex
scenes which utilized ray visibility.
Here's timing of koro.blend:
Without visibility check With visibility check
Original file 4min 20sec 4min 23sec
Camera rays only 1min 43 sec 55sec
Unfortunately, this doesn't come for free and requires extra data in
BVH node, which increases memory usage of BVH nodes by 15%. This we
can solve with some future trickery of avoiding __tri_storage created
for curve segments.
