[webkit-changes] [WebKit/WebKit] 9fd8cc: TextureMapperGL: edge distance anti-aliasing shoul...

[Fujii Hironori]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 9fd8ccc1aa9a931022ec6a5a28297733473b6e7a
      https://github.com/WebKit/WebKit/commit/9fd8ccc1aa9a931022ec6a5a28297733473b6e7a
  Author: Fujii Hironori <Hironori.Fujii at sony.com>
  Date:   2022-09-26 (Mon, 26 Sep 2022)

  Changed paths:
    M LayoutTests/platform/glib/TestExpectations
    M Source/WebCore/platform/graphics/texmap/TextureMapperShaderProgram.cpp

  Log Message:
  -----------
  TextureMapperGL: edge distance anti-aliasing should be calculated in homogeneous coordinates
https://bugs.webkit.org/show_bug.cgi?id=245265

Reviewed by Don Olmstead.

The edge distance anti-aliasing inflates rect edges by 1px in the
viewport coordinates and calculates an alpha value (v_antialias) for
each vertex to blur the edges. However, the viewport coordinates are
homogeneous coordinates. The projected vertex can be at infinity.
v_antialias also should be calculated in the homogeneous coordinates.

The denominator of v_antialias is same with one of the projected
vertex.

On the other hand, v_texCoord varying variable should be calculated
based on the 3D space distance.

* LayoutTests/platform/glib/TestExpectations:
* Source/WebCore/platform/graphics/texmap/TextureMapperShaderProgram.cpp:

Canonical link: https://commits.webkit.org/254885@main