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Bug 3790 - Memory leak with surfaces blitting on each other
Summary: Memory leak with surfaces blitting on each other
Status: RESOLVED FIXED
Alias: None
Product: SDL
Classification: Unclassified
Component: video (show other bugs)
Version: HG 2.0
Hardware: x86_64 Linux
: P2 normal
Assignee: Sam Lantinga
QA Contact: Sam Lantinga
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2017-08-31 05:54 UTC by bastien.bouclet
Modified: 2017-09-04 18:46 UTC (History)
0 users

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Description bastien.bouclet 2017-08-31 05:54:47 UTC 
When creating two surfaces and blitting them onto the other, SDL's internal reference counting fails, and one of the surfaces is not freed when calling SDL_FreeSurface.

Example code :

SDL_Surface *s1 = SDL_CreateRGBSurfaceWithFormat(0, 640, 480, 32, SDL_PIXELFORMAT_ARGB8888);
SDL_Surface *s2 = SDL_CreateRGBSurfaceWithFormat(0, 640, 480, 32, SDL_PIXELFORMAT_ARGB8888);

SDL_BlitSurface(s1, NULL, s2, NULL);
SDL_BlitSurface(s2, NULL, s1, NULL);

SDL_FreeSurface(s2);
SDL_FreeSurface(s1);

With this example, s1 is not freed after calling SDL_FreeSurface, its refcount attribute is still positive.

(Minimal example extracted from this code https://github.com/residualvm/residualvm/blob/master/backends/graphics/surfacesdl/surfacesdl-graphics.cpp)
Comment 1 Sam Lantinga 2017-09-04 18:46:37 UTC 
Fixed, thanks!
https://hg.libsdl.org/SDL/rev/52dcef74bdc5