Mercurial > sdl-ios-xcode

view docs/html/sdlcreatergbsurface.html @ 968:4675910b0b7b

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Date: Mon, 11 Oct 2004 15:17:27 +0300 (EEST) From: Hannu Savolainen Subject: Re: SDL uses obsolete OSS features I did some work on getting OSS to work better with SDL. There have been some problems with select which should be fixed now. I'm having some problems in understanding what is the purpose of the DSP_WaitAudio() routine. I added a return to the very beginning of this routine and commendted out the define for USE_BLOCKING_WRITES. At least lbreakout2 seems to work as well as earlier. The latencies are the same. An ordinary blocking write does exactly the same thing than DSP_WaitAudio does. So I would recommend using the USE_BLOCKING_WRITES approach and removing everything from the DSP_WaitAudio routine. Also enabling USE_BLOCKING_WRITES makes it possible to simplify DSP_PlayAudio() because you don't need to handle the partial writes (the do-while loop). Attached is a patch against SDL-1.2.7. After these changes SDL will use OSS as it's designed to be used (make it as simple as possible). This code should work with all OSS implementations because it uses only the very fundamental features that have been there since the jurassic times.
author Sam Lantinga <slouken@libsdl.org>
date Fri, 12 Nov 2004 21:39:04 +0000
parents 355632dca928
children
line wrap: on
line source

<HTML
><HEAD
><TITLE
>SDL_CreateRGBSurface</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_GetRGBA"
HREF="sdlgetrgba.html"><LINK
REL="NEXT"
TITLE="SDL_CreateRGBSurfaceFrom"
HREF="sdlcreatergbsurfacefrom.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="sdlgetrgba.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
></TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="sdlcreatergbsurfacefrom.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><H1
><A
NAME="SDLCREATERGBSURFACE"
></A
>SDL_CreateRGBSurface</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN1773"
></A
><H2
>Name</H2
>SDL_CreateRGBSurface&nbsp;--&nbsp;Create an empty SDL_Surface</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN1776"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN1777"
></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>SDL_Surface *<B
CLASS="FSFUNC"
>SDL_CreateRGBSurface</B
></CODE
>(Uint32 flags, int width, int height, int depth, Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1783"
></A
><H2
>Description</H2
><P
>Allocate an empty surface (must be called after <A
HREF="sdlsetvideomode.html"
>SDL_SetVideoMode</A
>)</P
><P
>If <TT
CLASS="PARAMETER"
><I
>depth</I
></TT
> is 8 bits an empty palette is allocated for the surface, otherwise a 'packed-pixel' <A
HREF="sdlpixelformat.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_PixelFormat</SPAN
></A
> is created using the <TT
CLASS="PARAMETER"
><I
>[RGBA]mask</I
></TT
>'s provided (see <A
HREF="sdlpixelformat.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_PixelFormat</SPAN
></A
>). The <TT
CLASS="PARAMETER"
><I
>flags</I
></TT
> specifies the type of surface that should be created, it is an OR'd combination of the following possible values.</P
><DIV
CLASS="INFORMALTABLE"
><A
NAME="AEN1795"
></A
><P
></P
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><TBODY
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_SWSURFACE</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>SDL will create the surface in system memory. This improves the performance of pixel level access, however you may not be able to take advantage of some types of hardware blitting.</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_HWSURFACE</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>SDL will attempt to create the surface in video memory. This will allow SDL to take advantage of Video-&#62;Video blits (which are often accelerated).</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_SRCCOLORKEY</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>This flag turns on colourkeying for blits from this surface. If
<TT
CLASS="LITERAL"
>SDL_HWSURFACE</TT
> is also specified and colourkeyed blits
are hardware-accelerated, then SDL will attempt to place the surface in
video memory.
Use <A
HREF="sdlsetcolorkey.html"
><TT
CLASS="FUNCTION"
>SDL_SetColorKey</TT
></A
>
to set or clear this flag after surface creation.</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_SRCALPHA</TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>This flag turns on alpha-blending for blits from this surface. If
<TT
CLASS="LITERAL"
>SDL_HWSURFACE</TT
> is also specified and alpha-blending blits
are hardware-accelerated, then the surface will be placed in video memory if
possible.
Use <A
HREF="sdlsetalpha.html"
><TT
CLASS="FUNCTION"
>SDL_SetAlpha</TT
></A
> to
set or clear this flag after surface creation.</TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Note: </B
>If an alpha-channel is specified (that is, if <TT
CLASS="PARAMETER"
><I
>Amask</I
></TT
> is
nonzero), then the <TT
CLASS="LITERAL"
>SDL_SRCALPHA</TT
> flag is automatically
set. You may remove this flag by calling 
<A
HREF="sdlsetalpha.html"
><TT
CLASS="FUNCTION"
>SDL_SetAlpha</TT
></A
>
after surface creation.</P
></BLOCKQUOTE
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1826"
></A
><H2
>Return Value</H2
><P
>Returns the created surface, or <SPAN
CLASS="RETURNVALUE"
>NULL</SPAN
> upon error.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1830"
></A
><H2
>Example</H2
><PRE
CLASS="PROGRAMLISTING"
>    /* Create a 32-bit surface with the bytes of each pixel in R,G,B,A order,
       as expected by OpenGL for textures */
    SDL_Surface *surface;
    Uint32 rmask, gmask, bmask, amask;

    /* SDL interprets each pixel as a 32-bit number, so our masks must depend
       on the endianness (byte order) of the machine */
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
    rmask = 0xff000000;
    gmask = 0x00ff0000;
    bmask = 0x0000ff00;
    amask = 0x000000ff;
#else
    rmask = 0x000000ff;
    gmask = 0x0000ff00;
    bmask = 0x00ff0000;
    amask = 0xff000000;
#endif

    surface = SDL_CreateRGBSurface(SDL_SWSURFACE, width, height, 32,
                                   rmask, gmask, bmask, amask);
    if(surface == NULL) {
        fprintf(stderr, "CreateRGBSurface failed: %s\n", SDL_GetError());
        exit(1);
    }</PRE
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1833"
></A
><H2
>See Also</H2
><P
><A
HREF="sdlcreatergbsurfacefrom.html"
><TT
CLASS="FUNCTION"
>SDL_CreateRGBSurfaceFrom</TT
></A
>,
<A
HREF="sdlfreesurface.html"
><TT
CLASS="FUNCTION"
>SDL_FreeSurface</TT
></A
>,
<A
HREF="sdlsetvideomode.html"
><TT
CLASS="FUNCTION"
>SDL_SetVideoMode</TT
></A
>,
<A
HREF="sdllocksurface.html"
><TT
CLASS="FUNCTION"
>SDL_LockSurface</TT
></A
>,
<A
HREF="sdlpixelformat.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_PixelFormat</SPAN
></A
>,
<A
HREF="sdlsurface.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_Surface</SPAN
></A
>
<A
HREF="sdlsetalpha.html"
><TT
CLASS="FUNCTION"
>SDL_SetAlpha</TT
></A
>
<A
HREF="sdlsetcolorkey.html"
><TT
CLASS="FUNCTION"
>SDL_SetColorKey</TT
></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="sdlgetrgba.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="sdlcreatergbsurfacefrom.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>SDL_GetRGBA</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_CreateRGBSurfaceFrom</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>