Webrender: Hit test / scrolling does not work in scrolling example

[fschutt]

I recently noticed that the scrolling example doesn't work anymore, no matter what I do. For some reason, the rectangles don't scroll anymore. The animation example still works (so transform / opacity keys still seem to work).

I only get this output on running the scrolling example:

OpenGL version 3.3 (Core Profile) Mesa 19.2.8
Shader resource path: None
Device pixel ratio: 1.25
Loading shaders...
Entering event loop
Hit test results:

Hit test results:

Hit test results:

Hit test results:

Hit test results:

Hit test results:

Hit test results:

Hit test results:

Hit test results:

Hit test results:

Theoretically there should be a list of rectangles that have been hit (i.e. the rectangles that need to be scrolled), but... nothing.

How to reproduce

git clone https://github.com/servo/webrender
cd webrender/examples
cargo run --bin scrolling

Then move the mouse cursor above the rectangles and see if scrolling works.

Additional info

• webrender version: https://github.com/servo/webrender/commit/02be1053a833a5490800260540adeb19611fcb0d
• rustc version:

rustc 1.41.0 (5e1a79984 2020-01-27)
binary: rustc
commit-hash: 5e1a799842ba6ed4a57e91f7ab9435947482f7d8
commit-date: 2020-01-27
host: x86_64-unknown-linux-gnu
release: 1.41.0
LLVM version: 9.0

[kvark]

https://bugzilla.mozilla.org/show_bug.cgi?id=1625693

[atouchet]

This was fixed in #3963.