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Bug 5046 - Crash on window resize when rendering on another thread
Summary: Crash on window resize when rendering on another thread
Status: RESOLVED FIXED
Alias: None
Product: SDL
Classification: Unclassified
Component: video (show other bugs)
Version: HG 2.0
Hardware: x86 macOS 10.15
: P2 normal
Assignee: Sam Lantinga
QA Contact: Sam Lantinga
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2020-03-20 08:56 UTC by Emir Marincic
Modified: 2020-03-20 19:10 UTC (History)
0 users

See Also:

Attachments
performSelectorOnMainThread patch (831 bytes, text/plain)
2020-03-20 08:56 UTC, Emir Marincic 		Details
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Description Emir Marincic 2020-03-20 08:56:40 UTC 
Created attachment 4271 [details]
performSelectorOnMainThread patch

Resizing a window schedules an update on the SDLOpenGLContext, the next swap on the auxiliary thread doing the rendering causes a [NSOpenGLContext update] on that thread, which is not allowed.

[NSOpenGLContext update] only started checking whether it's called from the main thread (through pthread_main_np) from Catalina onwards and AppKit uses _CFExecutableLinkedOnOrAfter to provide compatibility for older executables by setting NSOpenGLContextSuppressThreadAssertions.

I'm not sure if this should be supported but swapping on a separate thread works on enough platforms that we didn't notice this bug for years. Calling update on the main thread instead through performSelectorOnMainThread seems to work fine and after testing a couple of hours I didn't notice any undesired effects.

I've attached the patch I've been testing locally

Best regards
Emir
Comment 1 Sam Lantinga 2020-03-20 19:10:23 UTC 
Looks good, thanks!
https://hg.libsdl.org/SDL/rev/c8f27a5e868e