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SDL_LockSurface(3) SDL API Reference SDL_LockSurface(3) NAME SDL_LockSurface - Lock a surface for directly access. SYNOPSIS #include "SDL.h" int SDL_LockSurface(SDL_Surface *surface); DESCRIPTION SDL_LockSurface sets up a surface for directly accessing the pixels. Be- tween calls to SDL_LockSurface and SDL_UnlockSurface, you can write to and read from surface->pixels, using the pixel format stored in surface->for- mat. Once you are done accessing the surface, you should use SDL_UnlockSur- face to release it. Not all surfaces require locking. If SDL_MUSTLOCK(surface) evaluates to 0, then you can read and write to the surface at any time, and the pixel for- mat of the surface will not change. No operating system or library calls should be made between lock/unlock pairs, as critical system locks may be held during this time. It should be noted, that since SDL 1.1.8 surface locks are recursive. This means that you can lock a surface multiple times, but each lock must have a match unlock. . . SDL_LockSurface( surface ); . /* Surface is locked */ /* Direct pixel access on surface here */ . SDL_LockSurface( surface ); . /* More direct pixel access on surface */ . SDL_UnlockSurface( surface ); /* Surface is still locked */ /* Note: Is versions < 1.1.8, the surface would have been */ /* no longer locked at this stage */ . SDL_UnlockSurface( surface ); /* Surface is now unlocked */ . . RETURN VALUE SDL_LockSurface returns 0, or -1 if the surface couldn't be locked. SEE ALSO SDL_UnlockSurface SDL Tue 11 Sep 2001, 23:01 SDL_LockSurface(3)
NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | SEE ALSO
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