tree b8958387c892fc06ecbba57bcd779df9206aac50
parent db38022b7c5932c35e3965f999bf54b442d008c9
author Michael Ludwig <michaelludwig@google.com> 1579721531 -0500
committer Skia Commit-Bot <skia-commit-bot@chromium.org> 1579730639 +0000

Add GM reproducing perspective failures

Modeled on https://codepen.io/adamdupuis/pen/qLYzqB, this GM creates a
cube of rectangles with the camera at the center. It animates the FOV
since the original chrome issue was most visible when resizing the page
(which then updated the fov of the perspective css transform).

This draws correctly with the raster backend. There are two issues it
causes with Ganesh:

1. The input coordinates of some of the cube faces have 0 or negative ws.
  - When negative, the current bounds code does not perform clipping and
    just uses the mirrored point, which leads to misleading bounds.
  - When 0, the current bounds code produces infinities, and then GrOpsTask
    discards the op with non-finite bounds.
2. The anti-aliasing code also ignores w <= 0, and so all of its screen
   space math is incorrect.

This causes a mix of completely discarded draws and distorted draws on the
GPU backend.

Bug: skia:9779, chromium:224618
Change-Id: Ib00b909f51cbf7aaba5b89ed830ddc720ad3c73d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/265763
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>