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This is often invalid, outdated or misleading
especially when splitting files.
It's more useful to git-blame to find out who has developed the code.
See P901 for script to perform these edits.
Some functions always returned the input argument
which was never used.
This made code read as if there might be a leak.
Now return a boolean (true the imbuf is modified).
This commit implements multi-threaded calculation of frames
when building proxies. Both scaling and undistortion steps
are now threaded.
Frames and proxy resolution are still handled one-by-one,
saving files after every single step. So if HDD is not so
fast, this commit could have not so much benefit.
Internal changes:
- Added IMB_scaleImBuf_threaded which scales given image
buffer in multiple threads and uses bilinear filtering.
- libmv's camera intrinsics now have SetThreads() method
which is used to specify how many OpenMP threads to use
for buffer distortion/undistortion.
And yeah, this code is using OpenMP for threading.
- Reshuffled a bit libmv-capi calls and added function
BKE_tracking_distortion_set_threads to specify number
of threads used by intrinscis.
Additional changes:
- Made mipmapping operate with unsigned short instead of char
which allowed to eliminate extra division by 255, so prevision
should be a bit better now.
- Actually, this is not real unsigned short range, but it's a
range of 255*255 which is more convenient for mipmapping, so
made conversion functions private for scaling.c
Not sure it worth making this functions operate in 65535
range, for now current behavior seems to be just fine.
Regression was caused by alpha premul cleanup commit and the reason
of slowdown was uchar <-> float conversion which is slow.
Replaced with uchar <-> int conversion which seeps to be accurate
enough and mostly eliminates slowdown.
Slowdown was easy to notice when movie clip is used for 3d vierport
background and undistortion is enabled. In this case every frame
will re-calculate mipmaps.
It's still a nit slower than mipmap generation before cleanup
commit, but couldn't think about extra boost here atm.
This assumptions are now made:
- Internally float buffers are always linear alpha-premul colors
- Readers should worry about delivering float buffers with that
assumptions.
- There's an input image setting to say whether it's stored with
straight/premul alpha on the disk.
- Byte buffers are now assumed have straight alpha, readers should
deliver straight alpha.
Some implementation details:
- Removed scene's color unpremultiply setting, which was very
much confusing and was wrong for default settings.
Now all renderers assumes to deliver premultiplied alpha.
- IMB_buffer_byte_from_float will now linearize alpha when
converting from buffer.
- Sequencer's effects were changed to assume bytes have got
straight alpha. Most of effects will work with bytes still,
however for glow it was more tricky to avoid data loss, so
there's a commented out glow implementation which converts
byte buffer to floats first, operates on floats and returns
bytes back. It's slower and not sure if it should actually
be used -- who're using glow on alpha anyway?
- Sequencer modifiers should also be working nice with straight
bytes now.
- GLSL preview will predivide float textures to make nice shading,
shading with byte textures worked nice (GLSL was assuming straight
alpha).
- Blender Internal will set alpha=1 to the whole sky. The same
happens in Cycles and there's no way to avoid this -- sky is
neither straight nor premul and doesn't fit color pipeline well.
- Straight alpha mode for render result was also eliminated.
- Conversion to correct alpha need to be done before linearizing
float buffer.
- TIFF will now load and save files with proper alpha mode setting
in file meta data header.
- Remove Use Alpha from texture mapping and replaced with image
datablock setting.
Behaves much more predictable and clear from code point of view
and solves possible regressions when non-premultiplied images were
used as textures with ignoring alpha channel.
