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Fixed bug #89 Date: Sun, 23 Oct 2005 16:39:03 +0200 From: "A. Schmid" <sahib@phreaker.net> Subject: [SDL] no software surfaces with svgalib driver? Hi, I noticed that the SDL (1.2.9) svgalib driver only makes use of linear addressable (framebuffer) video modes. On older systems (like one of mine), linear addressable modes are often not available. Especially for cards with VESA VBE < 2.0 the svgalib vesa driver is unusable, since VESA only supports framebuffering for VBE 2.0 and later. The changes necessary to add support for software surfaces seem to be relatively small. I only had to hack src/video/svga/SDL_svgavideo.c (see attached patch). The code worked fine for me, but it is no more than a proof of concept and should be reviewed (probably has a memory leak when switching modes). It also uses the vgagl library (included in the svgalib package) and needs to be linked against it. -Alex
author Sam Lantinga <slouken@libsdl.org>
date Sun, 19 Mar 2006 12:05:16 +0000
parents 355632dca928
children f12379c41042
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><DIV
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>Chapter 12. Multi-threaded Programming</H1
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><DL
><DT
><B
>Table of Contents</B
></DT
><DT
><A
HREF="sdlcreatethread.html"
>SDL_CreateThread</A
>&nbsp;--&nbsp;Creates a new thread of execution that shares its parent's properties.</DT
><DT
><A
HREF="sdlthreadid.html"
>SDL_ThreadID</A
>&nbsp;--&nbsp;Get the 32-bit thread identifier for the current thread.</DT
><DT
><A
HREF="sdlgetthreadid.html"
>SDL_GetThreadID</A
>&nbsp;--&nbsp;Get the SDL thread ID of a SDL_Thread</DT
><DT
><A
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>SDL_WaitThread</A
>&nbsp;--&nbsp;Wait for a thread to finish.</DT
><DT
><A
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>SDL_KillThread</A
>&nbsp;--&nbsp;Gracelessly terminates the thread.</DT
><DT
><A
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>SDL_CreateMutex</A
>&nbsp;--&nbsp;Create a mutex</DT
><DT
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>SDL_DestroyMutex</A
>&nbsp;--&nbsp;Destroy a mutex</DT
><DT
><A
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>SDL_mutexP</A
>&nbsp;--&nbsp;Lock a mutex</DT
><DT
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>SDL_mutexV</A
>&nbsp;--&nbsp;Unlock a mutex</DT
><DT
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>SDL_CreateSemaphore</A
>&nbsp;--&nbsp;Creates a new semaphore and assigns an initial value to it.</DT
><DT
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>SDL_DestroySemaphore</A
>&nbsp;--&nbsp;Destroys a semaphore that was created by <A
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>SDL_CreateSemaphore</A
>.</DT
><DT
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>SDL_SemWait</A
>&nbsp;--&nbsp;Lock a semaphore and suspend the thread if the semaphore value is zero.</DT
><DT
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>SDL_SemTryWait</A
>&nbsp;--&nbsp;Attempt to lock a semaphore but don't suspend the thread.</DT
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>SDL_SemWaitTimeout</A
>&nbsp;--&nbsp;Lock a semaphore, but only wait up to a specified maximum time.</DT
><DT
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>SDL_SemPost</A
>&nbsp;--&nbsp;Unlock a semaphore.</DT
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>SDL_SemValue</A
>&nbsp;--&nbsp;Return the current value of a semaphore.</DT
><DT
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>SDL_CreateCond</A
>&nbsp;--&nbsp;Create a condition variable</DT
><DT
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>SDL_DestroyCond</A
>&nbsp;--&nbsp;Destroy a condition variable</DT
><DT
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>SDL_CondSignal</A
>&nbsp;--&nbsp;Restart a thread wait on a condition variable</DT
><DT
><A
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>SDL_CondBroadcast</A
>&nbsp;--&nbsp;Restart all threads waiting on a condition variable</DT
><DT
><A
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>SDL_CondWait</A
>&nbsp;--&nbsp;Wait on a condition variable</DT
><DT
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>SDL_CondWaitTimeout</A
>&nbsp;--&nbsp;Wait on a condition variable, with timeout</DT
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><P
>SDL provides functions for creating threads, mutexes, semphores and condition variables.</P
><P
>In general, you must be very aware of concurrency and data integrity issues
when writing multi-threaded programs.  Some good guidelines include:
<P
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><UL
><LI
><P
>Don't call SDL video/event functions from separate threads</P
></LI
><LI
><P
>Don't use any library functions in separate threads</P
></LI
><LI
><P
>Don't perform any memory management in separate threads</P
></LI
><LI
><P
>Lock global variables which may be accessed by multiple threads</P
></LI
><LI
><P
>Never terminate threads, always set a flag and wait for them to quit</P
></LI
><LI
><P
>Think very carefully about all possible ways your code may interact</P
></LI
></UL
></P
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><B
>Note: </B
>SDL's threading is not implemented on MacOS, due to that lack of preemptive thread support (MacOS X dos nt suffer from this problem)</P
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