Mercurial > sdl-ios-xcode
view docs/man3/SDL_SemWait.3 @ 3335:b8d313de8a65
Adam Strzelecki to SDL
Since current DirectFB implementation is incomplete for YUV surfaces (actually causes segmentation faults when trying Lock and use YUV planar textures) I decided to fix it a bit.
Here's a patch that should make DirectFB properly support YUV both packed and planar (3 planes).
(1) Removed SDL_BYTESPERPIXEL at all in favor of DFB_BYTES_PER_PIXEL(SDLToDFBPixelFormat(fmt)) which does return always proper BPP for YUVs too, coz SDL_BYTESPERPIXEL returns incorrect values for FOURCCs
(2) Fixed data->pixels allocation for planar YUVs in CreateTexture, it should allocate 150% more space
(3) Copy other planes for planar YUVs in UpdateTexture
(4) Moved checking if format is supported at all with DirectFB on CreateTexture at the beginning of the code
Waiting for comments,
--
Adam Strzelecki | nanoant.com
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Sun, 04 Oct 2009 04:03:37 +0000 |
| parents | 546f7c1eb755 |
| children | 1238da4a7112 |
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.TH "SDL_SemWait" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference" .SH "NAME" SDL_SemWait \- Lock a semaphore and suspend the thread if the semaphore value is zero\&. .SH "SYNOPSIS" .PP \fB#include "SDL\&.h" #include "SDL_thread\&.h" .sp \fBint \fBSDL_SemWait\fP\fR(\fBSDL_sem *sem\fR); .SH "DESCRIPTION" .PP \fBSDL_SemWait()\fP suspends the calling thread until either the semaphore pointed to by \fBsem\fR has a positive value, the call is interrupted by a signal or error\&. If the call is successful it will atomically decrement the semaphore value\&. .PP After \fBSDL_SemWait()\fP is successful, the semaphore can be released and its count atomically incremented by a successful call to \fISDL_SemPost\fR\&. .SH "RETURN VALUE" .PP Returns \fB0\fR if successful or \fB-1\fR if there was an error (leaving the semaphore unchanged)\&. .SH "EXAMPLES" .PP .PP .nf \f(CWif (SDL_SemWait(my_sem) == -1) { return WAIT_FAILED; } \&.\&.\&. SDL_SemPost(my_sem);\fR .fi .PP .SH "SEE ALSO" .PP \fI\fBSDL_CreateSemaphore\fP\fR, \fI\fBSDL_DestroySemaphore\fP\fR, \fI\fBSDL_SemTryWait\fP\fR, \fI\fBSDL_SemWaitTimeout\fP\fR, \fI\fBSDL_SemPost\fP\fR, \fI\fBSDL_SemValue\fP\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00