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Bug 5151 - Wayland: SDL ignores initial pointer position
Summary: Wayland: SDL ignores initial pointer position
Status: RESOLVED FIXED
Alias: None
Product: SDL
Classification: Unclassified
Component: video (show other bugs)
Version: HG 2.1
Hardware: x86_64 Linux
: P2 normal
Assignee: Sam Lantinga
QA Contact: Sam Lantinga
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2020-05-21 04:13 UTC by Tudor
Modified: 2020-05-29 22:53 UTC (History)
0 users

See Also:

Attachments
Attempt #1 (2.20 KB, patch)
2020-05-21 04:13 UTC, Tudor 		Details | Diff
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Description Tudor 2020-05-21 04:13:31 UTC 
Created attachment 4352 [details]
Attempt #1

A Wayland compositor may send a `pointer_enter` event with the coordinates of the pointer, followed by no (immediate) `pointer_motion` event. A simple case where this can happen is when a pointer confine is created: the compositor will warp the cursor to the SDL surface and emit a `pointer_enter` event, but no `pointer_motion`.

Since SDL only updates its internal position state on `pointer_motion`, this can lead to confusing results where the hardware cursor does not match where an SDL application thinks the cursor is.

I've attached a patch that addresses this issue, by treating `pointer_enter` as a "special" `pointer_motion` event.
Comment 1 Sam Lantinga 2020-05-29 22:53:50 UTC 
Looks good, thanks!
https://hg.libsdl.org/SDL/rev/a9b4bd264f3c