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Bug 2827

Summary: SDL_RenderCopy is extremely slow on iOS device after Emscripten commit
Product: SDL Reporter: Diego <diegoacevedo91>
Component: renderAssignee: Ryan C. Gordon <icculus>
Status: RESOLVED ABANDONED QA Contact: Sam Lantinga <slouken>
Severity: critical    
Priority: P2 CC: icculus
Version: HG 2.1   
Hardware: iPhone/iPod touch   
OS: iOS (All)   

Description Diego 2014-12-26 14:33:39 UTC 
Running happy.c from Xcode-iOS Demos project on a device produces this problem.
After changeset 9278 8900afb78a19, SDL_RenderCopy is slow on iOS devices. Timing happy.c's "render(renderer)" function produces ~200ms on 4S iOS 8, and ~100ms on 5C iOS 8.
The previous changeset 9277 f0bd40782fc7, runs as expected at ~5ms. 
This slowdown does not occur on the simulator.
Comment 1 Ryan C. Gordon 2014-12-26 19:59:03 UTC 
Can you go find GLES2_UpdateVertexBuffer() in src/render/opengles2/SDL_render_gles2.c?

https://hg.libsdl.org/SDL/file/8900afb78a19/src/render/opengles2/SDL_render_gles2.c#l1391

That "#if 0" line? Make that into "#if 1" and rebuild SDL and your app. Does that fix the problem?

--ryan.
Comment 2 Diego 2014-12-26 20:48:04 UTC 
Changing to "#if 1" worked!
Comment 3 Ryan C. Gordon 2014-12-27 03:31:40 UTC 
Ok, this should be fixed by https://hg.libsdl.org/SDL/rev/1d3bee66d518

I'm going to leave this bug assigned, because we should fix this properly after 2.0.4 ships, but the patch should make both Emscripten and iOS happy for now.

--ryan.
Comment 4 Ryan C. Gordon 2018-08-06 21:20:22 UTC 
Hello, and sorry if you're getting dozens of copies of this message by email.

We are closing out bugs that appear to be abandoned in some form. This can happen for lots of reasons: we couldn't reproduce it, conversation faded out, the bug was noted as fixed in a comment but we forgot to mark it resolved, the report is good but the fix is impractical, we fixed it a long time ago without realizing there was an associated report, etc.

Individually, any of these bugs might have a better resolution (such as WONTFIX or WORKSFORME or INVALID) but we've added a new resolution of ABANDONED to make this easily searchable and make it clear that it's not necessarily unreasonable to revive a given bug report.

So if this bug is still a going concern and you feel it should still be open: please feel free to reopen it! But unless you respond, we'd like to consider these bugs closed, as many of them are several years old and overwhelming our ability to prioritize recent issues.

(please note that hundred of bug reports were sorted through here, so we apologize for any human error. Just reopen the bug in that case!)

Thanks,
--ryan.