Mercurial > sdl-ios-xcode
view README.MacOS @ 1544:ab1e4c41ab71
Fixed bug #33
Mike Frysinger wrote:
> with libsdl-1.2.9, some games (like bomberclone) started
> segfaulting in Gentoo
[...snip...]
> the last change in the last hunk:
[...snip...]
> if i change the statement to read:
> (table[which].blit_features & GetBlitFeatures()) == GetBlitFeatures()
> bomberclone no longer segfaults on my box
Alex Volkov wrote:
> The test "(table[which].blit_features & GetBlitFeatures()) ==
> table[which].blit_features)" is correct, and the previous
> "(table[which].cpu_mmx == SDL_HasMMX())" was actually broken.
I think there is potentially a slightly different cause of the above problem.
During the introduction of the Altivec code, the blit_table struct field
'alpha' got changed from a straightforward enum to a bitmask, which makes
perfect sense by itself. However, now the table driven blitter selection code
in SDL_CalculateBlitN() can choose the wrong blitters when searching for a
NO_ALPHA blitter because of the following code:
int a_need = 0;
...
(a_need & table[which].alpha) == a_need &&
When searching through the normal_blit_2[] table, a SET_ALPHA blitter (like
Blit_RGB565_ARGB8888) can now be selected instead of a NO_ALPHA one, causing
alpha channel bits to appear in a non-alpha destination surface. I suppose this
could theoretically be an indirect cause of the segfault mentioned above.
I *think* this can be fixed by changing to
int a_need = NO_ALPHA;
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Wed, 15 Mar 2006 15:47:49 +0000 |
parents | 37e3ca9254c7 |
children |
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============================================================================== Using the Simple DirectMedia Layer with MacOS 7,8,9 on PPC ============================================================================== These instructions are for people using the Apple MPW environment: http://developer.apple.com/tools/mpw-tools/ CodeWarrior projects are available in the CWprojects directory. ============================================================================== I. Building the Simple DirectMedia Layer libraries: (This step isn't necessary if you have the SDL binary distribution) First, unpack the MPWmake.sea.hqx archive and move SDL.make into the SDL directory. Start MPW Set the current directory within MPW to the SDL toplevel directory. Build "SDL" (Type Command-B and enter "SDL" in the dialog) If everything compiles successfully, you now have the PPC libraries "SDL" and "SDLmain.o" in the 'lib' subdirectory. ============================================================================== II. Building the Simple DirectMedia Layer test programs: First, unpack the MPWmake.sea.hqx archive, move the new rsrc directory to the main SDL directory, and move the makefiles in the new test subdirectory to the SDL 'test' subdirectory. Start MPW Set the current directory within MPW to the SDL 'test' subdirectory. Build the programs that have an associated MPW makefile (file ending with .make), including "testwin", "testalpha", and "graywin". Copy the SDL library file into the test directory, and run! ============================================================================== III. Building the Simple DirectMedia Layer demo programs: Copy one of the test program Makefiles to the demo directory and modify it to match the sources in the demo. ============================================================================== IV. Enjoy! :) If you have a project you'd like me to know about, or want to ask questions, go ahead and join the SDL developer's mailing list by sending e-mail to: sdl-request@libsdl.org and put "subscribe" into the subject of the message. Or alternatively you can use the web interface: http://www.libsdl.org/mailman/listinfo/sdl ==============================================================================