[webkit-changes] [WebKit/WebKit] 437b55: [TextureMapper] Use linear sampling when blurring ...

[Commit Queue]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 437b5540d082a86c275db503fe8db8e0de51bbcc
      https://github.com/WebKit/WebKit/commit/437b5540d082a86c275db503fe8db8e0de51bbcc
  Author: Akihiro Kiuchi <Akihiro.Kiuchi at sony.com>
  Date:   2023-09-06 (Wed, 06 Sep 2023)

  Changed paths:
    M Source/WebCore/platform/graphics/texmap/TextureMapperGL.cpp
    M Source/WebCore/platform/graphics/texmap/TextureMapperShaderProgram.cpp
    M Source/WebCore/platform/graphics/texmap/TextureMapperShaderProgram.h

  Log Message:
  -----------
  [TextureMapper] Use linear sampling when blurring for better performance
https://bugs.webkit.org/show_bug.cgi?id=261102

Reviewed by Fujii Hironori.

To reduce the GPU load for gaussian blur, this fix reduces the size of
kernel use for the blur.

By adjusting the position(offset) to sample the texture and the weight
of each element of the kernel so that the linear interpolation during
texture sampling samples two texels and properly weights them, we can
reduce the size of the kernel without changing behaviour.

* Source/WebCore/platform/graphics/texmap/TextureMapperGL.cpp:
(WebCore::kernelHalfSizeToSimplifiedKernelHalfSize):
(WebCore::computeGaussianKernel):
(WebCore::TextureMapperGL::drawBlurred):
* Source/WebCore/platform/graphics/texmap/TextureMapperShaderProgram.cpp:
* Source/WebCore/platform/graphics/texmap/TextureMapperShaderProgram.h:

Canonical link: https://commits.webkit.org/267715@main