1<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 2<html xmlns="http://www.w3.org/1999/xhtml"> 3<head> 4<meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/> 5<meta http-equiv="X-UA-Compatible" content="IE=9"/> 6<title>SDL_gfx: I:/Sources/sdlgfx/SDL_framerate.c Source File</title> 7 8<link href="tabs.css" rel="stylesheet" type="text/css"/> 9<link href="doxygen.css" rel="stylesheet" type="text/css" /> 10 11 12 13</head> 14<body> 15<div id="top"><!-- do not remove this div! --> 16 17 18<div id="titlearea"> 19<table cellspacing="0" cellpadding="0"> 20 <tbody> 21 <tr style="height: 56px;"> 22 23 24 <td style="padding-left: 0.5em;"> 25 <div id="projectname">SDL_gfx 26  <span id="projectnumber">2.0.25</span> 27 </div> 28 29 </td> 30 31 32 33 </tr> 34 </tbody> 35</table> 36</div> 37 38<!-- Generated by Doxygen 1.8.0 --> 39 <div id="navrow1" class="tabs"> 40 <ul class="tablist"> 41 <li><a href="index.html"><span>Main Page</span></a></li> 42 <li><a href="annotated.html"><span>Data Structures</span></a></li> 43 <li class="current"><a href="files.html"><span>Files</span></a></li> 44 </ul> 45 </div> 46 <div id="navrow2" class="tabs2"> 47 <ul class="tablist"> 48 <li><a href="files.html"><span>File List</span></a></li> 49 <li><a href="globals.html"><span>Globals</span></a></li> 50 </ul> 51 </div> 52</div> 53<div class="header"> 54 <div class="headertitle"> 55<div class="title">I:/Sources/sdlgfx/SDL_framerate.c</div> </div> 56</div><!--header--> 57<div class="contents"> 58<a href="_s_d_l__framerate_8c.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">/*</span> 59<a name="l00002"></a>00002 <span class="comment"></span> 60<a name="l00003"></a>00003 <span class="comment">SDL_framerate.c: framerate manager</span> 61<a name="l00004"></a>00004 <span class="comment"></span> 62<a name="l00005"></a>00005 <span class="comment">Copyright (C) 2001-2012 Andreas Schiffler</span> 63<a name="l00006"></a>00006 <span class="comment"></span> 64<a name="l00007"></a>00007 <span class="comment">This software is provided 'as-is', without any express or implied</span> 65<a name="l00008"></a>00008 <span class="comment">warranty. In no event will the authors be held liable for any damages</span> 66<a name="l00009"></a>00009 <span class="comment">arising from the use of this software.</span> 67<a name="l00010"></a>00010 <span class="comment"></span> 68<a name="l00011"></a>00011 <span class="comment">Permission is granted to anyone to use this software for any purpose,</span> 69<a name="l00012"></a>00012 <span class="comment">including commercial applications, and to alter it and redistribute it</span> 70<a name="l00013"></a>00013 <span class="comment">freely, subject to the following restrictions:</span> 71<a name="l00014"></a>00014 <span class="comment"></span> 72<a name="l00015"></a>00015 <span class="comment">1. The origin of this software must not be misrepresented; you must not</span> 73<a name="l00016"></a>00016 <span class="comment">claim that you wrote the original software. If you use this software</span> 74<a name="l00017"></a>00017 <span class="comment">in a product, an acknowledgment in the product documentation would be</span> 75<a name="l00018"></a>00018 <span class="comment">appreciated but is not required.</span> 76<a name="l00019"></a>00019 <span class="comment"></span> 77<a name="l00020"></a>00020 <span class="comment">2. Altered source versions must be plainly marked as such, and must not be</span> 78<a name="l00021"></a>00021 <span class="comment">misrepresented as being the original software.</span> 79<a name="l00022"></a>00022 <span class="comment"></span> 80<a name="l00023"></a>00023 <span class="comment">3. This notice may not be removed or altered from any source</span> 81<a name="l00024"></a>00024 <span class="comment">distribution.</span> 82<a name="l00025"></a>00025 <span class="comment"></span> 83<a name="l00026"></a>00026 <span class="comment">Andreas Schiffler -- aschiffler at ferzkopp dot net</span> 84<a name="l00027"></a>00027 <span class="comment"></span> 85<a name="l00028"></a>00028 <span class="comment">*/</span> 86<a name="l00029"></a>00029 87<a name="l00030"></a>00030 <span class="preprocessor">#include "<a class="code" href="_s_d_l__framerate_8h.html">SDL_framerate.h</a>"</span> 88<a name="l00031"></a>00031 89<a name="l00037"></a><a class="code" href="_s_d_l__framerate_8c.html#a3bed31ab61648f7d69c8f47c90161cfe">00037</a> Uint32 <a class="code" href="_s_d_l__framerate_8c.html#a3bed31ab61648f7d69c8f47c90161cfe" title="Internal wrapper to SDL_GetTicks that ensures a non-zero return value.">_getTicks</a>() 90<a name="l00038"></a>00038 { 91<a name="l00039"></a>00039 Uint32 ticks = SDL_GetTicks(); 92<a name="l00040"></a>00040 93<a name="l00041"></a>00041 <span class="comment">/* </span> 94<a name="l00042"></a>00042 <span class="comment"> * Since baseticks!=0 is used to track initialization</span> 95<a name="l00043"></a>00043 <span class="comment"> * we need to ensure that the tick count is always >0 </span> 96<a name="l00044"></a>00044 <span class="comment"> * since SDL_GetTicks may not have incremented yet and</span> 97<a name="l00045"></a>00045 <span class="comment"> * return 0 depending on the timing of the calls.</span> 98<a name="l00046"></a>00046 <span class="comment"> */</span> 99<a name="l00047"></a>00047 <span class="keywordflow">if</span> (ticks == 0) { 100<a name="l00048"></a>00048 <span class="keywordflow">return</span> 1; 101<a name="l00049"></a>00049 } <span class="keywordflow">else</span> { 102<a name="l00050"></a>00050 <span class="keywordflow">return</span> ticks; 103<a name="l00051"></a>00051 } 104<a name="l00052"></a>00052 } 105<a name="l00053"></a>00053 106<a name="l00062"></a><a class="code" href="_s_d_l__framerate_8h.html#a3ca69231486837c809fdcbe5b0a10787">00062</a> <span class="keywordtype">void</span> <a class="code" href="_s_d_l__framerate_8c.html#a444ebaaaa6b1ceeafa921562bdab1a44" title="Initialize the framerate manager.">SDL_initFramerate</a>(<a class="code" href="struct_f_p_smanager.html" title="Structure holding the state and timing information of the framerate controller.">FPSmanager</a> * manager) 107<a name="l00063"></a>00063 { 108<a name="l00064"></a>00064 <span class="comment">/*</span> 109<a name="l00065"></a>00065 <span class="comment"> * Store some sane values </span> 110<a name="l00066"></a>00066 <span class="comment"> */</span> 111<a name="l00067"></a>00067 manager-><a class="code" href="struct_f_p_smanager.html#a05019faae5de8486dbb69d24b24eed78">framecount</a> = 0; 112<a name="l00068"></a>00068 manager-><a class="code" href="struct_f_p_smanager.html#af7eec7342fd8eb48d5f49ba7f5b91853">rate</a> = <a class="code" href="_s_d_l__framerate_8h.html#ab3ac02e6acb348129a019b9f20aa5c90" title="Default rate of framerate controller in Hz (1/s).">FPS_DEFAULT</a>; 113<a name="l00069"></a>00069 manager-><a class="code" href="struct_f_p_smanager.html#a48695d55d40900a197688bb773b9d431">rateticks</a> = (1000.0f / (float) <a class="code" href="_s_d_l__framerate_8h.html#ab3ac02e6acb348129a019b9f20aa5c90" title="Default rate of framerate controller in Hz (1/s).">FPS_DEFAULT</a>); 114<a name="l00070"></a>00070 manager-><a class="code" href="struct_f_p_smanager.html#ad853f9c03e200a77fd897c1ea3aec43d">baseticks</a> = <a class="code" href="_s_d_l__framerate_8c.html#a3bed31ab61648f7d69c8f47c90161cfe" title="Internal wrapper to SDL_GetTicks that ensures a non-zero return value.">_getTicks</a>(); 115<a name="l00071"></a>00071 manager-><a class="code" href="struct_f_p_smanager.html#aa7716779b7cc57dee24c15d7c5d62e55">lastticks</a> = manager-><a class="code" href="struct_f_p_smanager.html#ad853f9c03e200a77fd897c1ea3aec43d">baseticks</a>; 116<a name="l00072"></a>00072 117<a name="l00073"></a>00073 } 118<a name="l00074"></a>00074 119<a name="l00086"></a><a class="code" href="_s_d_l__framerate_8h.html#a186ef8e6b1ee4ab36e05b162545fb0e4">00086</a> <span class="keywordtype">int</span> <a class="code" href="_s_d_l__framerate_8c.html#afad4b503cf9719daced45fa4d9653d72" title="Set the framerate in Hz.">SDL_setFramerate</a>(<a class="code" href="struct_f_p_smanager.html" title="Structure holding the state and timing information of the framerate controller.">FPSmanager</a> * manager, Uint32 rate) 120<a name="l00087"></a>00087 { 121<a name="l00088"></a>00088 <span class="keywordflow">if</span> ((rate >= <a class="code" href="_s_d_l__framerate_8h.html#a9555dceeaaffdd2669c991e6a300085b" title="Lowest possible rate supported by framerate controller in Hz (1/s).">FPS_LOWER_LIMIT</a>) && (rate <= <a class="code" href="_s_d_l__framerate_8h.html#aeaeac0f0b439344496e29abf60904d58" title="Highest possible rate supported by framerate controller in Hz (1/s).">FPS_UPPER_LIMIT</a>)) { 122<a name="l00089"></a>00089 manager-><a class="code" href="struct_f_p_smanager.html#a05019faae5de8486dbb69d24b24eed78">framecount</a> = 0; 123<a name="l00090"></a>00090 manager-><a class="code" href="struct_f_p_smanager.html#af7eec7342fd8eb48d5f49ba7f5b91853">rate</a> = rate; 124<a name="l00091"></a>00091 manager-><a class="code" href="struct_f_p_smanager.html#a48695d55d40900a197688bb773b9d431">rateticks</a> = (1000.0f / (float) rate); 125<a name="l00092"></a>00092 <span class="keywordflow">return</span> (0); 126<a name="l00093"></a>00093 } <span class="keywordflow">else</span> { 127<a name="l00094"></a>00094 <span class="keywordflow">return</span> (-1); 128<a name="l00095"></a>00095 } 129<a name="l00096"></a>00096 } 130<a name="l00097"></a>00097 131<a name="l00107"></a><a class="code" href="_s_d_l__framerate_8h.html#adeb2ddd02412527aad226ba453a21999">00107</a> <span class="keywordtype">int</span> <a class="code" href="_s_d_l__framerate_8c.html#a575bb511d6f817ad846a788cbd08ae91" title="Return the current target framerate in Hz.">SDL_getFramerate</a>(<a class="code" href="struct_f_p_smanager.html" title="Structure holding the state and timing information of the framerate controller.">FPSmanager</a> * manager) 132<a name="l00108"></a>00108 { 133<a name="l00109"></a>00109 <span class="keywordflow">if</span> (manager == NULL) { 134<a name="l00110"></a>00110 <span class="keywordflow">return</span> (-1); 135<a name="l00111"></a>00111 } <span class="keywordflow">else</span> { 136<a name="l00112"></a>00112 <span class="keywordflow">return</span> ((<span class="keywordtype">int</span>)manager-><a class="code" href="struct_f_p_smanager.html#af7eec7342fd8eb48d5f49ba7f5b91853">rate</a>); 137<a name="l00113"></a>00113 } 138<a name="l00114"></a>00114 } 139<a name="l00115"></a>00115 140<a name="l00126"></a><a class="code" href="_s_d_l__framerate_8h.html#a3f3b7da73f3d92ff82b069b6108aa7ad">00126</a> <span class="keywordtype">int</span> <a class="code" href="_s_d_l__framerate_8c.html#a96b13e26f8436222e866904a592a6eec" title="Return the current framecount.">SDL_getFramecount</a>(<a class="code" href="struct_f_p_smanager.html" title="Structure holding the state and timing information of the framerate controller.">FPSmanager</a> * manager) 141<a name="l00127"></a>00127 { 142<a name="l00128"></a>00128 <span class="keywordflow">if</span> (manager == NULL) { 143<a name="l00129"></a>00129 <span class="keywordflow">return</span> (-1); 144<a name="l00130"></a>00130 } <span class="keywordflow">else</span> { 145<a name="l00131"></a>00131 <span class="keywordflow">return</span> ((<span class="keywordtype">int</span>)manager-><a class="code" href="struct_f_p_smanager.html#a05019faae5de8486dbb69d24b24eed78">framecount</a>); 146<a name="l00132"></a>00132 } 147<a name="l00133"></a>00133 } 148<a name="l00134"></a>00134 149<a name="l00146"></a><a class="code" href="_s_d_l__framerate_8h.html#a2c452933d7376dbb0083304b760ed63b">00146</a> Uint32 <a class="code" href="_s_d_l__framerate_8c.html#afce13fa3dd37130deb4975d8b230c3ba" title="Delay execution to maintain a constant framerate and calculate fps.">SDL_framerateDelay</a>(<a class="code" href="struct_f_p_smanager.html" title="Structure holding the state and timing information of the framerate controller.">FPSmanager</a> * manager) 150<a name="l00147"></a>00147 { 151<a name="l00148"></a>00148 Uint32 current_ticks; 152<a name="l00149"></a>00149 Uint32 target_ticks; 153<a name="l00150"></a>00150 Uint32 the_delay; 154<a name="l00151"></a>00151 Uint32 time_passed = 0; 155<a name="l00152"></a>00152 156<a name="l00153"></a>00153 <span class="comment">/*</span> 157<a name="l00154"></a>00154 <span class="comment"> * No manager, no delay</span> 158<a name="l00155"></a>00155 <span class="comment"> */</span> 159<a name="l00156"></a>00156 <span class="keywordflow">if</span> (manager == NULL) { 160<a name="l00157"></a>00157 <span class="keywordflow">return</span> 0; 161<a name="l00158"></a>00158 } 162<a name="l00159"></a>00159 163<a name="l00160"></a>00160 <span class="comment">/*</span> 164<a name="l00161"></a>00161 <span class="comment"> * Initialize uninitialized manager </span> 165<a name="l00162"></a>00162 <span class="comment"> */</span> 166<a name="l00163"></a>00163 <span class="keywordflow">if</span> (manager-><a class="code" href="struct_f_p_smanager.html#ad853f9c03e200a77fd897c1ea3aec43d">baseticks</a> == 0) { 167<a name="l00164"></a>00164 <a class="code" href="_s_d_l__framerate_8c.html#a444ebaaaa6b1ceeafa921562bdab1a44" title="Initialize the framerate manager.">SDL_initFramerate</a>(manager); 168<a name="l00165"></a>00165 } 169<a name="l00166"></a>00166 170<a name="l00167"></a>00167 <span class="comment">/*</span> 171<a name="l00168"></a>00168 <span class="comment"> * Next frame </span> 172<a name="l00169"></a>00169 <span class="comment"> */</span> 173<a name="l00170"></a>00170 manager-><a class="code" href="struct_f_p_smanager.html#a05019faae5de8486dbb69d24b24eed78">framecount</a>++; 174<a name="l00171"></a>00171 175<a name="l00172"></a>00172 <span class="comment">/*</span> 176<a name="l00173"></a>00173 <span class="comment"> * Get/calc ticks </span> 177<a name="l00174"></a>00174 <span class="comment"> */</span> 178<a name="l00175"></a>00175 current_ticks = <a class="code" href="_s_d_l__framerate_8c.html#a3bed31ab61648f7d69c8f47c90161cfe" title="Internal wrapper to SDL_GetTicks that ensures a non-zero return value.">_getTicks</a>(); 179<a name="l00176"></a>00176 time_passed = current_ticks - manager-><a class="code" href="struct_f_p_smanager.html#aa7716779b7cc57dee24c15d7c5d62e55">lastticks</a>; 180<a name="l00177"></a>00177 manager-><a class="code" href="struct_f_p_smanager.html#aa7716779b7cc57dee24c15d7c5d62e55">lastticks</a> = current_ticks; 181<a name="l00178"></a>00178 target_ticks = manager-><a class="code" href="struct_f_p_smanager.html#ad853f9c03e200a77fd897c1ea3aec43d">baseticks</a> + (Uint32) ((<span class="keywordtype">float</span>) manager-><a class="code" href="struct_f_p_smanager.html#a05019faae5de8486dbb69d24b24eed78">framecount</a> * manager-><a class="code" href="struct_f_p_smanager.html#a48695d55d40900a197688bb773b9d431">rateticks</a>); 182<a name="l00179"></a>00179 183<a name="l00180"></a>00180 <span class="keywordflow">if</span> (current_ticks <= target_ticks) { 184<a name="l00181"></a>00181 the_delay = target_ticks - current_ticks; 185<a name="l00182"></a>00182 SDL_Delay(the_delay); 186<a name="l00183"></a>00183 } <span class="keywordflow">else</span> { 187<a name="l00184"></a>00184 manager-><a class="code" href="struct_f_p_smanager.html#a05019faae5de8486dbb69d24b24eed78">framecount</a> = 0; 188<a name="l00185"></a>00185 manager-><a class="code" href="struct_f_p_smanager.html#ad853f9c03e200a77fd897c1ea3aec43d">baseticks</a> = <a class="code" href="_s_d_l__framerate_8c.html#a3bed31ab61648f7d69c8f47c90161cfe" title="Internal wrapper to SDL_GetTicks that ensures a non-zero return value.">_getTicks</a>(); 189<a name="l00186"></a>00186 } 190<a name="l00187"></a>00187 191<a name="l00188"></a>00188 <span class="keywordflow">return</span> time_passed; 192<a name="l00189"></a>00189 } 193</pre></div></div><!-- contents --> 194 195 196<hr class="footer"/><address class="footer"><small> 197Generated by  <a href="http://www.doxygen.org/index.html"> 198<img class="footer" src="doxygen.png" alt="doxygen"/> 199</a> 1.8.0 200</small></address> 201 202</body> 203</html> 204
