API: merged IMB_scalefastImBuf, IMB_scaleImBuf, IMB_scaleImBuf_threaded
into one function IMB_scale with enum IMBScaleFilter {Nearest, Bilinear, Box}
and bool "threaded" param.
Performance:
- Box filtering (nee IMB_scaleImBuf) can be multi-threaded now.
- Nearest filtering (nee IMB_scalefastImBuf) can be multi-threaded now.
Also fix performance regression on float images caused by fix in #126234
- Bilinear filtering (nee IMB_scaleImBuf_threaded) is several times faster now.
Correctness:
- Nearest and Box filtering: no longer loses half of edge pixels when scaling
up.
- Box: fixed garbage results (and possible out of bounds reads) for non-4
channel float images.
- Bilinear: no longer shifts image when scaling up.
- Bilinear: properly filters when scaling down by 2x2.
Test coverage:
- Add gtest coverage for various IMB_scale modes.
- Add a IMB_performance_test performance test, ran manually.
More details, images and performance numbers in PR.
Pull Request: https://projects.blender.org/blender/blender/pulls/126390
6d93bf6b44