Mercurial > sdl-ios-xcode

view docs/html/time.html @ 1982:3b4ce57c6215

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
First shot at new audio data types (int32 and float32). Notable changes: - Converters between types are autogenerated. Instead of making multiple passes over the data with seperate filters for endianess, size, signedness, etc, converting between data types is always one specialized filter. This simplifies SDL_BuildAudioCVT(), which otherwise had a million edge cases with the new types, and makes the actually conversions more CPU cache friendly. Left a stub for adding specific optimized versions of these routines (SSE/MMX/Altivec, assembler, etc) - Autogenerated converters are built by SDL/src/audio/sdlgenaudiocvt.pl. This does not need to be run unless tweaking the code, and thus doesn't need integration into the build system. - Went through all the drivers and tried to weed out all the "Uint16" references that are better specified with the new SDL_AudioFormat typedef. - Cleaned out a bunch of hardcoded bitwise magic numbers and replaced them with new SDL_AUDIO_* macros. - Added initial float32 and int32 support code. Theoretically, existing drivers will push these through converters to get the data they want to feed to the hardware. Still TODO: - Optimize and debug new converters. - Update the CoreAudio backend to accept float32 data directly. - Other backends, too? - SDL_LoadWAV() needs to be updated to support int32 and float32 .wav files (both of which exist and can be generated by 'sox' for testing purposes). - Update the mixer to handle new datatypes. - Optionally update SDL_sound and SDL_mixer, etc.
author Ryan C. Gordon <icculus@icculus.org>
date Thu, 24 Aug 2006 12:10:46 +0000
parents 355632dca928
children
line wrap: on
line source

<HTML
><HEAD
><TITLE
>Time</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="SDL Reference"
HREF="reference.html"><LINK
REL="PREVIOUS"
TITLE="SDL_CondWaitTimeout"
HREF="sdlcondwaittimeout.html"><LINK
REL="NEXT"
TITLE="SDL_GetTicks"
HREF="sdlgetticks.html"><META
NAME="KEYWORD"
CONTENT="time"><META
NAME="KEYWORD"
CONTENT="function"></HEAD
><BODY
CLASS="CHAPTER"
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="sdlcondwaittimeout.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
></TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="sdlgetticks.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="CHAPTER"
><H1
><A
NAME="TIME"
></A
>Chapter 13. Time</H1
><DIV
CLASS="TOC"
><DL
><DT
><B
>Table of Contents</B
></DT
><DT
><A
HREF="sdlgetticks.html"
>SDL_GetTicks</A
>&nbsp;--&nbsp;Get the number of milliseconds since the SDL library initialization.</DT
><DT
><A
HREF="sdldelay.html"
>SDL_Delay</A
>&nbsp;--&nbsp;Wait a specified number of milliseconds before returning.</DT
><DT
><A
HREF="sdladdtimer.html"
>SDL_AddTimer</A
>&nbsp;--&nbsp;Add a timer which will call a callback after the specified number of milliseconds has
elapsed.</DT
><DT
><A
HREF="sdlremovetimer.html"
>SDL_RemoveTimer</A
>&nbsp;--&nbsp;Remove a timer which was added with
<A
HREF="sdladdtimer.html"
>SDL_AddTimer</A
>.</DT
><DT
><A
HREF="sdlsettimer.html"
>SDL_SetTimer</A
>&nbsp;--&nbsp;Set a callback to run after the specified number of milliseconds has
elapsed.</DT
></DL
></DIV
><P
>SDL provides several cross-platform functions for dealing with time.
It provides a way to get the current time, a way to wait a little while,
and a simple timer mechanism.  These functions give you two ways of moving an
object every x milliseconds:

<P
></P
><UL
><LI
><P
>Use a timer callback function.  This may have the bad effect that it runs in a seperate thread or uses alarm signals, but it's easier to implement.</P
></LI
><LI
><P
>Or you can get the number of milliseconds passed, and move the object if, for example, 30 ms passed.</P
></LI
></UL
>&#13;</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="sdlcondwaittimeout.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="sdlgetticks.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>SDL_CondWaitTimeout</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="reference.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>SDL_GetTicks</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>