The BLI bicubic interpolation function with border boundary is wrong
around edges. It returns zero, where interpolated values should exist.
This is due to a wrong early exit condition, where only a 2x2 window is
assumed instead of the 4x4 window considered by bicubic interpolation.
To fix this, assume a 2 pixel region in the early exit condition for
both directions.
Pull Request: https://projects.blender.org/blender/blender/pulls/131320
The BLI wrapmode variant of nearest interpolation for border boundary is
wrong for coordinates between [-1, 0]. That's because the negative
comparison in wrap_coord is done on the integer rounded coordinates,
which will be zero in this case, so the condition will not fail. To fix
this, do the comparison on the original coordinates instead.
Pull Request: https://projects.blender.org/blender/blender/pulls/131306
Implements #130836:
interpolate_*_wrapmode_fl take InterpWrapMode wrap_u and wrap_v arguments.
U and V coordinate axes can have different wrap modes: clamp/extend,
border/zero, wrap/repeat.
Note that this removes inconsistency where cubic interpolation was
returning zero for samples completely outside the image, but all other
functions were not, and the behavior was not matching the function
documentation either.
Use the new functions in the new compositor CPU backend.
Possible performance impact for other places (e.g. VSE): measured on
4K resolution, transformed (scaled and rotated) 4K EXR image:
- Nearest filter: no change,
- Bilinear filter: no change,
- Cubic BSpline filter: slight performance decrease, IMB_transform
19.5 -> 20.7 ms (Ryzen 5950X, VS2022). Feels acceptable.
Pull Request: https://projects.blender.org/blender/blender/pulls/130893
This is because sse2neon.h might be used to emulate SSE intrinsics
on ARM64 architecture, and it uses some preprocessor which is not
available for C language when using MSVC.
The old-style math file math_matrix.c uses this header, so needed
to become C++. Simple rename did not work since there is a new math
utility math_matrix.cc exists. Following some existing convention
the math_matrix.c is renamed to math_matrix_c.cc. Eventually all the
code should switch to use C++ style math, and the C style removed,
so it seems reasonable to not mix old and new style of API in the
same file.
There should be no functional changes.
Pull Request: https://projects.blender.org/blender/blender/pulls/121335
Commit 8b9743eb40 already made Blender be compiled with SSE4.2 flags
on x64 architecture, which kicked in the SSE4 code paths in
BLI_math_interp functions.
Which made them faster, e.g. in VSE on Windows/Ryzen5950X, scaling
up an image to 4K resolution:
- Bilinear 5.8ms -> 5.3ms
- Cubic Mitchell 16.3ms -> 15.7ms
This change removes the now-unneeded SSE pre-SSE4 code paths for
_mm_floor_ps, _mm_min_epi32 and _mm_max_epi32 emulation.
Additionally, including BLI_simd.h on SSE4 platform now includes
the necessary SSE4 intrinsics header.
Pull Request: https://projects.blender.org/blender/blender/pulls/120583
The BLI image interpolation function with clamped boundary returns zero
for out of bound pixels. That's because the neighbour pixel wrapping
condition disregarded the border template argument. To fix this, only
handle that condition if in border mode.
Pull Request: https://projects.blender.org/blender/blender/pulls/119164
Part of overall "improve image filtering situation" (#116980), this PR addresses
two issues:
- Bilinear (default) image filtering makes half a source pixel wide transparent
border around the image. This is very noticeable when scaling images/movies up
in VSE. However, when there is no scaling up but you have slightly rotated
image, this creates a "somewhat nice" anti-aliasing around the edge.
- The other filtering kinds (e.g. cubic) do not have this behavior. So they do
not create unexpected transparency when scaling up (yay), however for slightly
rotated images the edge is "jagged" (oh no).
More detail and images in PR.
Pull Request: https://projects.blender.org/blender/blender/pulls/117717
Part of overall "improve filtering situation" (#116980) task:
Add "Cubic Mitchell" filtering option to VSE strips. This is a cubic (4x4)
filter that generally looks better than bilinear, while not blurring the image
as much as the Cubic BSpline filter that exists elsewhere within Blender. It is
also default in many other apps.
Rename the (very recently added) VSE Bicubic filter option to Cubic BSpline.
Images in the PR.
Pull Request: https://projects.blender.org/blender/blender/pulls/117517
There exist a bunch of "give me a (filtered) image pixel at this location"
functions, some with duplicated functionality, some with almost the same but
not quite, some that look similar but behave slightly differently, etc.
Some of them were in BLI, some were in ImBuf.
This commit tries to improve the situation by:
* Adding low level interpolation functions to `BLI_math_interp.hh`
- With documentation on their behavior,
- And with more unit tests.
* At `ImBuf` level, there are only convenience inline wrappers to the above BLI
functions (split off into a separate header `IMB_interp.hh`). However, since
these wrappers are inline, some things get a tiny bit faster as a side
effect. E.g. VSE image strip, scaling to 4K resolution (Windows/Ryzen5950X):
- Nearest filter: 2.33 -> 1.94ms
- Bilinear filter: 5.83 -> 5.69ms
- Subsampled3x3 filter: 28.6 -> 22.4ms
Details on the functions:
- All of them have `_byte` and `_fl` suffixes.
- They exist in 4-channel byte (uchar4) and float (float4), as well as
explicitly passed amount of channels for other float images.
- New functions in BLI `blender::math` namespace:
- `interpolate_nearest`
- `interpolate_bilinear`
- `interpolate_bilinear_wrap`. Note that unlike previous "wrap" function,
this one no longer requires the caller to do their own wrapping.
- `interpolate_cubic_bspline`. Previous similar function was called just
"bicubic" which could mean many different things.
- Same functions exist in `IMB_interp.hh`, they are just convenience that takes
ImBuf and uses data pointer, width, height from that.
Other bits:
- Renamed `mod_f_positive` to `floored_fmod` (better matches `safe_floored_modf`
and `floored_modulo` that exist elsewhere), made it branchless and added more
unit tests.
- `interpolate_bilinear_wrap_fl` no longer clamps result to 0..1 range. Instead,
moved the clamp to be outside of the call in `paint_image_proj.cc` and
`paint_utils.cc`. Though the need for clamping in there is also questionable.
Pull Request: https://projects.blender.org/blender/blender/pulls/117387
Part of overall "improve filtering situation" (#116980) task:
* Add Bicubic filtering option to strip Transform "Filter" setting.
Previously this option only existed in Transform Effect "Interpolation"
setting.
- With this addition, it feels like the transform effect could
possibly be marked as legacy/deprecated, since the regular Transform
that is on all strips can do everything that Transform Effect did?
* Speed up bicubic filtering (used now in VSE, but also in CPU Compositor,
image paint, etc.) by slightly simplifying the code and using some SIMD.
Upscaling 96x54 image to 3840x2160 resolution, using Bicubic filtering:
- Windows (VS2022, Ryzen 5950X): 35.5ms -> 15.1ms
- Mac (clang 15, M1 Max): 29.6ms -> 24.4ms
* Add gtest coverage for bicubic functionality.
Pull Request: https://projects.blender.org/blender/blender/pulls/117100
