annotate docs/man3/SDL_LockSurface.3 @ 914:bbf8dcc8aed6

Date: Wed, 23 Jun 2004 17:05:33 -0400 From: Chris Nelson Subject: [SDL] [Patch] WiseGroup MP-8800 / MP-8866 (PS2 Joystick) In the current cvs version, SDL doesn't handle these Playstation2 controller => USB adapters correctly, in linux. It will always assume that the maximum number of joysticks (2 in the case of the MP-8866, 4 in the case of the 8800) are plugged in. This is bad not only because it allows SDL to exaggerate the number of logical joysticks, but primarily because the joystick axes are mapped incorrectly, all over the place, such that the devices are effectively unusable unless you have the maximum number of joysticks plugged in. My changes to src/joystick/linux/SDL_sysjoystick.c build on another's previous work (which was a special case for this very joystick, actually), and fix both of these problems, as well as making the current code a little more general, to allow for others to more easily drop in code for quirky joysticks such as these. I've tested this code under 2.6.7 as well as 2.4.24... Both work as advertised (provided you load the JOYDEV linux code as a module, otherwise they won't work at all, new code or old, but that's another issue entirely). Though this sounds horribly formal, you have my permission to distribute all of my work on this issue under the LGPL. So there.
author Sam Lantinga <slouken@libsdl.org>
date Sun, 25 Jul 2004 18:31:50 +0000
parents e5bc29de3f0a
children 546f7c1eb755
rev   line source
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1 .TH "SDL_LockSurface" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference"
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2 .SH "NAME"
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3 SDL_LockSurface\- Lock a surface for directly access\&.
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4 .SH "SYNOPSIS"
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5 .PP
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6 \fB#include "SDL\&.h"
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7 .sp
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8 \fBint \fBSDL_LockSurface\fP\fR(\fBSDL_Surface *surface\fR);
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9 .SH "DESCRIPTION"
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10 .PP
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11 \fBSDL_LockSurface\fP sets up a surface for directly accessing the pixels\&. Between calls to \fBSDL_LockSurface\fP and \fBSDL_UnlockSurface\fP, you can write to and read from \fBsurface->\fBpixels\fR\fR, using the pixel format stored in \fBsurface->\fBformat\fR\fR\&. Once you are done accessing the surface, you should use \fBSDL_UnlockSurface\fP to release it\&.
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12 .PP
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13 Not all surfaces require locking\&. If \fBSDL_MUSTLOCK\fP(\fBsurface\fR) evaluates to \fB0\fR, then you can read and write to the surface at any time, and the pixel format of the surface will not change\&.
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14 .PP
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15 No operating system or library calls should be made between lock/unlock pairs, as critical system locks may be held during this time\&.
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16 .PP
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17 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\&.
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18 .PP
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19 .nf
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20 \f(CW \&.
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21 \&.
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22 SDL_LockSurface( surface );
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23 \&.
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24 /* Surface is locked */
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25 /* Direct pixel access on surface here */
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26 \&.
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27 SDL_LockSurface( surface );
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28 \&.
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29 /* More direct pixel access on surface */
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30 \&.
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31 SDL_UnlockSurface( surface );
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32 /* Surface is still locked */
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33 /* Note: Is versions < 1\&.1\&.8, the surface would have been */
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34 /* no longer locked at this stage */
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35 \&.
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36 SDL_UnlockSurface( surface );
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37 /* Surface is now unlocked */
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38 \&.
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39 \&.\fR
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40 .fi
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41 .PP
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42 .SH "RETURN VALUE"
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43 .PP
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44 \fBSDL_LockSurface\fP returns \fB0\fR, or \fB-1\fR if the surface couldn\&'t be locked\&.
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45 .SH "SEE ALSO"
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46 .PP
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47 \fI\fBSDL_UnlockSurface\fP\fR
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48 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01