view docs/html/sdldisplayyuvoverlay.html @ 3899:081aecdb0911 SDL-1.2

From: Gabriel Gambetta To: SDL Mailing List <sdl@libsdl.org> Date: Fri, 17 Nov 2006 00:39:29 -0200 Subject: [SDL] Alpha blending bug - fixed? It turns out mm5 never got the correct value. This failed : [...] "movd %1, %%mm5\n\t" : : "m" (amask), "m" (sf->Ashift) ); mm5 got 0xFF000018 instead of 0x00000018. However I did this : Uint32 ashift = sf->Ashift; [...] "movd %1, %%mm5\n\t" : : "m" (amask), "m" (ashift) ); and everything worked fine. The only thing I could find out was that ashift is 32-bit aligned but sf->Ashift isn't: printf("ashift %8X [%d]\n", &ashift, (int)(&ashift) % 4); printf("sf->Ashift %8X [%d]\n", &sf->Ashift, (int)(&sf->Ashift) % 4); ashift at BFF0E0C4 [0] sf->Ashift at 08AFB9CD [1] Could this be the problem? If it is, the fix is extremely trivial. Should I submit a patch? --Gabriel
author Ryan C. Gordon <icculus@icculus.org>
date Tue, 21 Nov 2006 23:17:00 +0000
parents 355632dca928
children
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>SDL_DisplayYUVOverlay</H1
><DIV
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><A
NAME="AEN2908"
></A
><H2
>Name</H2
>SDL_DisplayYUVOverlay&nbsp;--&nbsp;Blit the overlay to the display</DIV
><DIV
CLASS="REFSYNOPSISDIV"
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><H2
>Synopsis</H2
><DIV
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><P
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><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_DisplayYUVOverlay</B
></CODE
>(SDL_Overlay *overlay, SDL_Rect *dstrect);</CODE
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><H2
>Description</H2
><P
>Blit the <TT
CLASS="PARAMETER"
><I
>overlay</I
></TT
> to the surface specified when it was <A
HREF="sdlcreateyuvoverlay.html"
>created</A
>. The <A
HREF="sdlrect.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_Rect</SPAN
></A
> structure, <TT
CLASS="PARAMETER"
><I
>dstrect</I
></TT
>, specifies the position and size of the destination. If the <TT
CLASS="PARAMETER"
><I
>dstrect</I
></TT
> is a larger or smaller than the overlay then the overlay will be scaled, this is optimized for 2x scaling.</P
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><A
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><H2
>Return Values</H2
><P
>Returns 0 on success</P
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></A
><H2
>See Also</H2
><P
><A
HREF="sdloverlay.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_Overlay</SPAN
></A
>,
<A
HREF="sdlcreateyuvoverlay.html"
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>SDL_CreateYUVOverlay</TT
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