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Date: Thu, 17 Jun 2004 11:38:51 -0700 (PDT) From: Eric Wing <ewing2121@yahoo.com> Subject: New OS X patch (was Re: [SDL] Bug with inverted mouse coordinates in I have a new patch for OS X I would like to submit. First, it appears no further action has been taken on my fix from Apple on the OpenGL windowed mode mouse inversion problem. The fix would reunify the code, and no longer require case checking for which version of the OS you are running. This is probably a good fix because the behavior with the old code could change again with future versions of the OS, so those fixes are included in this new patch. But in addition, when I was at Apple, I asked them about the ability to distinguish between the modifier keys on the left and right sides of the keyboard (e.g. Left Shift, Right Shift, Left/Right Alt, L/R Cmd, L/R Ctrl). They told me that starting with Panther, the OS began supporting this feature. This has always been a source of annoyance for me when bringing a program that comes from Windows or Linux to OS X when the keybindings happened to need distinguishable left-side and right-side keys. So the rest of the patch I am submitting contains new code to support this feature on Panther (and presumably later versions of the OS). So after removing the OS version checks for the mouse inversion problem, I reused the OS version checks to activate the Left/Right detection of modifier keys. If you are running Panther (or above), the new code will attempt to distinguish between sides. For the older OS's, the code path reverts to the original code. I've tested with Panther on a G4 Cube, G5 dual processor, and Powerbook Rev C. The Cube and G5 keyboards demonstrated the ability to distinguish between sides. The Powerbook seems to only have left-side keys, but the patch was still able to handle it by producing the same results as before the patch. I also wanted to test a non-Apple keyboard. Unfortunately, I don't have any PC USB keyboards. However, I was able to borrow a Sun Microsystems USB keyboard, so I tried that out on the G5, and I got the correct behavior for left and right sides. I'm expecting that if it worked with a Sun keyboard, most other keyboards should work with no problems.
author Sam Lantinga <slouken@libsdl.org>
date Fri, 20 Aug 2004 22:35:23 +0000
parents 355632dca928
children
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<HTML
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><TITLE
>SDL_LockSurface</TITLE
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><H1
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>SDL_LockSurface</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN1919"
></A
><H2
>Name</H2
>SDL_LockSurface&nbsp;--&nbsp;Lock a surface for directly access.</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN1922"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN1923"
></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_LockSurface</B
></CODE
>(SDL_Surface *surface);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1929"
></A
><H2
>Description</H2
><P
><TT
CLASS="FUNCTION"
>SDL_LockSurface</TT
> sets up a surface for directly 
accessing the pixels.  Between calls to <TT
CLASS="FUNCTION"
>SDL_LockSurface</TT
>
and <TT
CLASS="FUNCTION"
>SDL_UnlockSurface</TT
>, you can write to and read from 
<TT
CLASS="PARAMETER"
><I
>surface-&#62;<TT
CLASS="STRUCTFIELD"
><I
>pixels</I
></TT
></I
></TT
>, using the pixel format stored in
<TT
CLASS="PARAMETER"
><I
>surface-&#62;<TT
CLASS="STRUCTFIELD"
><I
>format</I
></TT
></I
></TT
>.  Once you are done accessing the
surface, you should use <TT
CLASS="FUNCTION"
>SDL_UnlockSurface</TT
> to release it.</P
><P
>Not all surfaces require locking.  
If <TT
CLASS="LITERAL"
>SDL_MUSTLOCK</TT
>(<TT
CLASS="PARAMETER"
><I
>surface</I
></TT
>)
evaluates to <SPAN
CLASS="RETURNVALUE"
>0</SPAN
>, then you can read and write to the 
surface at any time, and the pixel format of the surface will not change. </P
><P
>No operating system or library calls should be made between lock/unlock
pairs, as critical system locks may be held during this time.</P
><P
>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.
<PRE
CLASS="PROGRAMLISTING"
>    .
    .
    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 &#60; 1.1.8, the surface would have been */
    /* no longer locked at this stage                         */
    .
    SDL_UnlockSurface( surface );
    /* Surface is now unlocked */
    .
    .</PRE
></P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1947"
></A
><H2
>Return Value</H2
><P
><TT
CLASS="FUNCTION"
>SDL_LockSurface</TT
> returns <SPAN
CLASS="RETURNVALUE"
>0</SPAN
>, 
or <SPAN
CLASS="RETURNVALUE"
>-1</SPAN
> if the surface couldn't be locked.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1953"
></A
><H2
>See Also</H2
><P
><A
HREF="sdlunlocksurface.html"
><TT
CLASS="FUNCTION"
>SDL_UnlockSurface</TT
></A
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