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From Bug #36:
There are a couple of issues with the selection of Altivec alpha-blitting
routines in CalculateAlphaBlit() in src/video/SDL_Blit_A.c.
1) There's no check for the presence of Altivec when checking if the
Blit32to565PixelAlphaAltivec() routine can be selected.
2) Altivec cannot be used in video memory, and there's no check if the
destination surface is a hardware surface. (Alpha-blitting to a hardware
surface with GPU support is a bad idea, but somebody's bound to do it anyway.)
Patch to fix these attached.
author | Ryan C. Gordon <icculus@icculus.org> |
---|---|
date | Sun, 08 Jan 2006 21:18:15 +0000 |
parents | 355632dca928 |
children |
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<HTML ><HEAD ><TITLE >SDL_ConvertSurface</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ "><LINK REL="HOME" TITLE="SDL Library Documentation" HREF="index.html"><LINK REL="UP" TITLE="Video" HREF="video.html"><LINK REL="PREVIOUS" TITLE="SDL_GetClipRect" HREF="sdlgetcliprect.html"><LINK REL="NEXT" TITLE="SDL_BlitSurface" HREF="sdlblitsurface.html"></HEAD ><BODY CLASS="REFENTRY" BGCOLOR="#FFF8DC" TEXT="#000000" LINK="#0000ee" VLINK="#551a8b" ALINK="#ff0000" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >SDL Library Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="sdlgetcliprect.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlblitsurface.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLCONVERTSURFACE" ></A >SDL_ConvertSurface</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN2258" ></A ><H2 >Name</H2 >SDL_ConvertSurface -- Converts a surface to the same format as another surface.</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN2261" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN2262" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL/SDL.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >SDL_Surface *<B CLASS="FSFUNC" >SDL_ConvertSurface</B ></CODE >(SDL_Surface *src, SDL_PixelFormat *fmt, Uint32 flags);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN2268" ></A ><H2 >Description</H2 ><P >Creates a new surface of the specified format, and then copies and maps the given surface to it. If this function fails, it returns <TT CLASS="LITERAL" >NULL</TT >.</P ><P >The <TT CLASS="PARAMETER" ><I >flags</I ></TT > parameter is passed to <A HREF="sdlcreatergbsurface.html" ><TT CLASS="FUNCTION" >SDL_CreateRGBSurface</TT ></A > and has those semantics.</P ><P >This function is used internally by <A HREF="sdldisplayformat.html" ><TT CLASS="FUNCTION" >SDL_DisplayFormat</TT ></A >.</P ><P >This function can only be called after SDL_Init.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN2280" ></A ><H2 >Return Value</H2 ><P >Returns either a pointer to the new surface, or <TT CLASS="LITERAL" >NULL</TT > on error.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN2284" ></A ><H2 >See Also</H2 ><P ><A HREF="sdlcreatergbsurface.html" ><TT CLASS="FUNCTION" >SDL_CreateRGBSurface</TT ></A >, <A HREF="sdldisplayformat.html" ><TT CLASS="FUNCTION" >SDL_DisplayFormat</TT ></A >, <A HREF="sdlpixelformat.html" ><SPAN CLASS="STRUCTNAME" >SDL_PixelFormat</SPAN ></A >, <A HREF="sdlsurface.html" ><SPAN CLASS="STRUCTNAME" >SDL_Surface</SPAN ></A ></P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="sdlgetcliprect.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="sdlblitsurface.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_GetClipRect</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="video.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_BlitSurface</TD ></TR ></TABLE ></DIV ></BODY ></HTML >