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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 355632dca928
children
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<HTML
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>SDL_GL_LoadLibrary</TITLE
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>SDL_GL_LoadLibrary</H1
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><H2
>Name</H2
>SDL_GL_LoadLibrary&nbsp;--&nbsp;Specify an OpenGL library</DIV
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>Synopsis</H2
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><P
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><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
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>SDL_GL_LoadLibrary</B
></CODE
>(const char *path);</CODE
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><H2
>Description</H2
><P
>If you wish, you may load the OpenGL library at runtime, this must be done before <A
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><TT
CLASS="FUNCTION"
>SDL_SetVideoMode</TT
></A
> is called. The <TT
CLASS="PARAMETER"
><I
>path</I
></TT
> of the GL library is passed to <TT
CLASS="FUNCTION"
>SDL_GL_LoadLibrary</TT
> and it returns <SPAN
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>0</SPAN
> on success, or <SPAN
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>-1</SPAN
> on an error. You must then use <A
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><TT
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>SDL_GL_GetProcAddress</TT
></A
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>SDL_GL_GetProcAddress</TT
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