1<HTML 2><HEAD 3><TITLE 4>Time Examples</TITLE 5><META 6NAME="GENERATOR" 7CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ 8"><LINK 9REL="HOME" 10TITLE="SDL Library Documentation" 11HREF="index.html"><LINK 12REL="UP" 13TITLE="Examples" 14HREF="guideexamples.html"><LINK 15REL="PREVIOUS" 16TITLE="CDROM Examples" 17HREF="guidecdromexamples.html"><LINK 18REL="NEXT" 19TITLE="SDL Reference" 20HREF="reference.html"></HEAD 21><BODY 22CLASS="SECT1" 23BGCOLOR="#FFF8DC" 24TEXT="#000000" 25LINK="#0000ee" 26VLINK="#551a8b" 27ALINK="#ff0000" 28><DIV 29CLASS="NAVHEADER" 30><TABLE 31SUMMARY="Header navigation table" 32WIDTH="100%" 33BORDER="0" 34CELLPADDING="0" 35CELLSPACING="0" 36><TR 37><TH 38COLSPAN="3" 39ALIGN="center" 40>SDL Library Documentation</TH 41></TR 42><TR 43><TD 44WIDTH="10%" 45ALIGN="left" 46VALIGN="bottom" 47><A 48HREF="guidecdromexamples.html" 49ACCESSKEY="P" 50>Prev</A 51></TD 52><TD 53WIDTH="80%" 54ALIGN="center" 55VALIGN="bottom" 56>Chapter 4. Examples</TD 57><TD 58WIDTH="10%" 59ALIGN="right" 60VALIGN="bottom" 61><A 62HREF="reference.html" 63ACCESSKEY="N" 64>Next</A 65></TD 66></TR 67></TABLE 68><HR 69ALIGN="LEFT" 70WIDTH="100%"></DIV 71><DIV 72CLASS="SECT1" 73><H1 74CLASS="SECT1" 75><A 76NAME="GUIDETIMEEXAMPLES" 77></A 78>Time Examples</H1 79><P 80></P 81><DIV 82CLASS="SECT2" 83><H2 84CLASS="SECT2" 85><A 86NAME="AEN412" 87></A 88>Time based game loop</H2 89><P 90><PRE 91CLASS="PROGRAMLISTING" 92>#define TICK_INTERVAL 30 93 94static Uint32 next_time; 95 96Uint32 time_left(void) 97{ 98 Uint32 now; 99 100 now = SDL_GetTicks(); 101 if(next_time <= now) 102 return 0; 103 else 104 return next_time - now; 105} 106 107 108/* main game loop */ 109 110 next_time = SDL_GetTicks() + TICK_INTERVAL; 111 while ( game_running ) { 112 update_game_state(); 113 SDL_Delay(time_left()); 114 next_time += TICK_INTERVAL; 115 } </PRE 116></P 117></DIV 118></DIV 119><DIV 120CLASS="NAVFOOTER" 121><HR 122ALIGN="LEFT" 123WIDTH="100%"><TABLE 124SUMMARY="Footer navigation table" 125WIDTH="100%" 126BORDER="0" 127CELLPADDING="0" 128CELLSPACING="0" 129><TR 130><TD 131WIDTH="33%" 132ALIGN="left" 133VALIGN="top" 134><A 135HREF="guidecdromexamples.html" 136ACCESSKEY="P" 137>Prev</A 138></TD 139><TD 140WIDTH="34%" 141ALIGN="center" 142VALIGN="top" 143><A 144HREF="index.html" 145ACCESSKEY="H" 146>Home</A 147></TD 148><TD 149WIDTH="33%" 150ALIGN="right" 151VALIGN="top" 152><A 153HREF="reference.html" 154ACCESSKEY="N" 155>Next</A 156></TD 157></TR 158><TR 159><TD 160WIDTH="33%" 161ALIGN="left" 162VALIGN="top" 163>CDROM Examples</TD 164><TD 165WIDTH="34%" 166ALIGN="center" 167VALIGN="top" 168><A 169HREF="guideexamples.html" 170ACCESSKEY="U" 171>Up</A 172></TD 173><TD 174WIDTH="33%" 175ALIGN="right" 176VALIGN="top" 177>SDL Reference</TD 178></TR 179></TABLE 180></DIV 181></BODY 182></HTML 183>