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Date: Wed, 1 Feb 2006 18:20:33 -0800 From: Eric Wing Subject: SDL/Universal Binary updates Hi Sam, Attached is a big set of changes to the Xcode projects to support Universal Binaries. I have also included .dmgs that include the prebuilt frameworks. Ryan, I also updated SMPEG which is also in the package. The SDL and smpeg binaries were built against the CVS version (pulled maybe a month ago?). I do not have an Intel Mac to test on so I have no idea if this stuff actually works. However, Christian Walther has been a big help in testing 10.2.8 and 10.3.9 so I'm fairly confident we got the build settings correct for at least PPC. I have attempted to document the important things for producing these Universal Binaries. Documentation is somewhat scattered through out everything, but there is a big centralized piece of documentation in the UniversalBinaryNotes.rtf in the SDL.dmg. As far as Universal Binaries are concerned, the big things were: - Build with gcc 3.3 on PPC, 4.0 on Intel. - We couldn't get any of the MMX/SSE code to compile/link (SDL and smpeg). - All 3rd party dependencies had to be rebuilt as Universal There were also a bunch of non-Universal things that have been updated: - I converted the SDL-satellites to create .dmg's instead of .pkg installers - Updated all 3rd party static libraries with current versions. (I think libpng was the most dramatic going from 1.0.? to 1.2.8 with API breakage. I haven't found any problems so far in doing this.) - Changed some compiler optimization settings - Finally updated the exports list for SDL_mixer - Tried to include a static smpeg in SDL_mixer (multiple build variants in Xcode project now) - Enabled Altivec in SDL (we forgot to add the flags to Xcode last time) - More documentation Since so many things have changed, there might be new problems introduced. The big issue I've found so far is with SDL_mixer. As I mentioned on the mailing list, MP3's produce an assertion failure. And the MikMod problem reported on Bugzilla continues to persist. There's probably a bunch of other stuff I'm forgetting. There really were hundreds of little things I mucked with so it's hard to remember them all. If you have any questions, feel free to ask. Thanks, Eric
author Sam Lantinga <slouken@libsdl.org>
date Thu, 02 Feb 2006 06:26:39 +0000
parents 355632dca928
children
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<HTML
><HEAD
><TITLE
>SDL_SetAlpha</TITLE
><META
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><HR
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><H1
><A
NAME="SDLSETALPHA"
></A
>SDL_SetAlpha</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN2096"
></A
><H2
>Name</H2
>SDL_SetAlpha&nbsp;--&nbsp;Adjust the alpha properties of a surface</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN2099"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN2100"
></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_SetAlpha</B
></CODE
>(SDL_Surface *surface, Uint32 flag, Uint8 alpha);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN2106"
></A
><H2
>Description</H2
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Note: </B
>This function and the semantics of SDL alpha blending have changed since version 1.1.4. Up until version 1.1.5, an alpha value of 0 was considered opaque and a value of 255 was considered transparent. This has now been inverted: 0 (<TT
CLASS="LITERAL"
>SDL_ALPHA_TRANSPARENT</TT
>) is now considered transparent and 255 (<TT
CLASS="LITERAL"
>SDL_ALPHA_OPAQUE</TT
>) is now considered opaque.</P
></BLOCKQUOTE
></DIV
><P
><TT
CLASS="FUNCTION"
>SDL_SetAlpha</TT
> is used for setting the per-surface alpha
value and/or enabling and disabling alpha blending.</P
><P
>The<TT
CLASS="PARAMETER"
><I
>surface</I
></TT
> parameter specifies which surface whose alpha
attributes you wish to adjust. <TT
CLASS="PARAMETER"
><I
>flags</I
></TT
> is used to specify
whether alpha blending should be used (<TT
CLASS="LITERAL"
>SDL_SRCALPHA</TT
>) and
whether the surface should use RLE acceleration for blitting
(<TT
CLASS="LITERAL"
>SDL_RLEACCEL</TT
>). <TT
CLASS="PARAMETER"
><I
>flags</I
></TT
> can be an OR'd
combination of these two options, one of these options or 0. If
<TT
CLASS="LITERAL"
>SDL_SRCALPHA</TT
> is not passed as a flag then all alpha
information is ignored when blitting the surface. The
<TT
CLASS="PARAMETER"
><I
>alpha</I
></TT
> parameter is the per-surface alpha value; a
surface need not have an alpha channel to use per-surface alpha and blitting
can still be accelerated with <TT
CLASS="LITERAL"
>SDL_RLEACCEL</TT
>.</P
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Note: </B
>The per-surface alpha value of 128 is considered a special case and
is optimised, so it's much faster than other per-surface values.</P
></BLOCKQUOTE
></DIV
><P
>Alpha effects surface blitting in the following ways:</P
><DIV
CLASS="INFORMALTABLE"
><A
NAME="AEN2126"
></A
><P
></P
><TABLE
BORDER="0"
CLASS="CALSTABLE"
><TBODY
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
>RGBA-&#62;RGB with <TT
CLASS="LITERAL"
>SDL_SRCALPHA</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><P
>The source is alpha-blended with the destination, using the alpha channel. <TT
CLASS="LITERAL"
>SDL_SRCCOLORKEY</TT
> and the per-surface alpha are ignored.</P
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
>RGBA-&#62;RGB without <TT
CLASS="LITERAL"
>SDL_SRCALPHA</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><P
>The RGB data is copied from the source. The source alpha channel and the per-surface alpha value are ignored.</P
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
>RGB-&#62;RGBA with <TT
CLASS="LITERAL"
>SDL_SRCALPHA</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><P
>The source is alpha-blended with the destination using the per-surface alpha
value. If <TT
CLASS="LITERAL"
>SDL_SRCCOLORKEY</TT
> is set, only the pixels not
matching the colorkey value are copied. The alpha channel of the copied pixels
is set to opaque.</P
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
>RGB-&#62;RGBA without <TT
CLASS="LITERAL"
>SDL_SRCALPHA</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><P
>The RGB data is copied from the source and the alpha value of the copied pixels
is set to opaque. If <TT
CLASS="LITERAL"
>SDL_SRCCOLORKEY</TT
> is set, only the pixels
not matching the colorkey value are copied. </P
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
>RGBA-&#62;RGBA with <TT
CLASS="LITERAL"
>SDL_SRCALPHA</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><P
>The source is alpha-blended with the destination using the source alpha
channel. The alpha channel in the destination surface is left untouched.
<TT
CLASS="LITERAL"
>SDL_SRCCOLORKEY</TT
> is ignored.</P
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
>RGBA-&#62;RGBA without <TT
CLASS="LITERAL"
>SDL_SRCALPHA</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><P
>The RGBA data is copied to the destination surface. If <TT
CLASS="LITERAL"
>SDL_SRCCOLORKEY</TT
> is set, only the pixels not matching the colorkey value are copied.</P
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
>RGB-&#62;RGB with <TT
CLASS="LITERAL"
>SDL_SRCALPHA</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><P
>The source is alpha-blended with the destination using the per-surface alpha value. If <TT
CLASS="LITERAL"
>SDL_SRCCOLORKEY</TT
> is set, only the pixels not matching the colorkey value are copied.</P
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
>RGB-&#62;RGB without <TT
CLASS="LITERAL"
>SDL_SRCALPHA</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><P
>The RGB data is copied from the source. If <TT
CLASS="LITERAL"
>SDL_SRCCOLORKEY</TT
> is set, only the pixels not matching the colorkey value are copied.</P
></TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Note: </B
> Note that RGBA-&#62;RGBA blits (with SDL_SRCALPHA set) keep the alpha
of the destination surface. This means that you cannot compose two arbitrary
RGBA surfaces this way and get the result you would expect from "overlaying"
them; the destination alpha will work as a mask.</P
><P
>Also note that per-pixel and per-surface alpha cannot be combined;
the per-pixel alpha is always used if available</P
></BLOCKQUOTE
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN2179"
></A
><H2
>Return Value</H2
><P
>This function returns <SPAN
CLASS="RETURNVALUE"
>0</SPAN
>, or
<SPAN
CLASS="RETURNVALUE"
>-1</SPAN
> if there was an error.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN2184"
></A
><H2
>See Also</H2
><P
><A
HREF="sdlmaprgba.html"
><TT
CLASS="FUNCTION"
>SDL_MapRGBA</TT
></A
>,
<A
HREF="sdlgetrgba.html"
><TT
CLASS="FUNCTION"
>SDL_GetRGBA</TT
></A
>,
<A
HREF="sdldisplayformatalpha.html"
><TT
CLASS="FUNCTION"
>SDL_DisplayFormatAlpha</TT
></A
>,
<A
HREF="sdlblitsurface.html"
><TT
CLASS="FUNCTION"
>SDL_BlitSurface</TT
></A
></P
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