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<a href="#func-members">Functions</a> |
<a href="#var-members">Variables</a> </div>
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<div class="title">Fast trig functions<div class="ingroups"><a class="el" href="group__lib8tion.html">Fast math functions</a></div></div> </div>
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<p>Fast 8 and 16-bit approximations of sin(x) and cos(x).
<a href="#details">More...</a></p>
<div id="dynsection-0" onclick="return toggleVisibility(this)" class="dynheader closed" style="cursor:pointer;">
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<center><table><tr><td><img src="group___trig.png" border="0" alt="" usemap="#group______trig"/>
<map name="group______trig" id="group______trig">
<area shape="rect" id="node2" href="group__lib8tion.html" title="A variety of functions for working with numbers. " alt="" coords="5,5,144,32"/></map>
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<table class="memberdecls">
<tr class="heading"><td colspan="2"><h2 class="groupheader"><a name="func-members"></a>
Functions</h2></td></tr>
<tr class="memitem:ga660ff60bfc5116525e50187de72009fc"><td class="memItemLeft" align="right" valign="top">LIB8STATIC int16_t </td><td class="memItemRight" valign="bottom"><a class="el" href="group___trig.html#ga660ff60bfc5116525e50187de72009fc">sin16_avr</a> (uint16_t theta)</td></tr>
<tr class="memdesc:ga660ff60bfc5116525e50187de72009fc"><td class="mdescLeft"> </td><td class="mdescRight">Fast 16-bit approximation of sin(x). <a href="#ga660ff60bfc5116525e50187de72009fc">More...</a><br /></td></tr>
<tr class="separator:ga660ff60bfc5116525e50187de72009fc"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:ga0890962cb06b267617f4b06d7e9be5eb"><td class="memItemLeft" align="right" valign="top">LIB8STATIC int16_t </td><td class="memItemRight" valign="bottom"><a class="el" href="group___trig.html#ga0890962cb06b267617f4b06d7e9be5eb">sin16_C</a> (uint16_t theta)</td></tr>
<tr class="memdesc:ga0890962cb06b267617f4b06d7e9be5eb"><td class="mdescLeft"> </td><td class="mdescRight">Fast 16-bit approximation of sin(x). <a href="#ga0890962cb06b267617f4b06d7e9be5eb">More...</a><br /></td></tr>
<tr class="separator:ga0890962cb06b267617f4b06d7e9be5eb"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:ga056952ebed39f55880bb353857b47075"><td class="memItemLeft" align="right" valign="top">LIB8STATIC int16_t </td><td class="memItemRight" valign="bottom"><a class="el" href="group___trig.html#ga056952ebed39f55880bb353857b47075">cos16</a> (uint16_t theta)</td></tr>
<tr class="memdesc:ga056952ebed39f55880bb353857b47075"><td class="mdescLeft"> </td><td class="mdescRight">Fast 16-bit approximation of cos(x). <a href="#ga056952ebed39f55880bb353857b47075">More...</a><br /></td></tr>
<tr class="separator:ga056952ebed39f55880bb353857b47075"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:ga6aa1f993cbbc427d80da1ee2ccca86e7"><td class="memItemLeft" align="right" valign="top">LIB8STATIC uint8_t </td><td class="memItemRight" valign="bottom"><a class="el" href="group___trig.html#ga6aa1f993cbbc427d80da1ee2ccca86e7">sin8_avr</a> (uint8_t theta)</td></tr>
<tr class="memdesc:ga6aa1f993cbbc427d80da1ee2ccca86e7"><td class="mdescLeft"> </td><td class="mdescRight">Fast 8-bit approximation of sin(x). <a href="#ga6aa1f993cbbc427d80da1ee2ccca86e7">More...</a><br /></td></tr>
<tr class="separator:ga6aa1f993cbbc427d80da1ee2ccca86e7"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:ga46933a9b42921c6605588268d11f7c1e"><td class="memItemLeft" align="right" valign="top">LIB8STATIC uint8_t </td><td class="memItemRight" valign="bottom"><a class="el" href="group___trig.html#ga46933a9b42921c6605588268d11f7c1e">sin8_C</a> (uint8_t theta)</td></tr>
<tr class="memdesc:ga46933a9b42921c6605588268d11f7c1e"><td class="mdescLeft"> </td><td class="mdescRight">Fast 8-bit approximation of sin(x). <a href="#ga46933a9b42921c6605588268d11f7c1e">More...</a><br /></td></tr>
<tr class="separator:ga46933a9b42921c6605588268d11f7c1e"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:ga4432f985c94f5bff715db402d767b0e8"><td class="memItemLeft" align="right" valign="top">LIB8STATIC uint8_t </td><td class="memItemRight" valign="bottom"><a class="el" href="group___trig.html#ga4432f985c94f5bff715db402d767b0e8">cos8</a> (uint8_t theta)</td></tr>
<tr class="memdesc:ga4432f985c94f5bff715db402d767b0e8"><td class="mdescLeft"> </td><td class="mdescRight">Fast 8-bit approximation of cos(x). <a href="#ga4432f985c94f5bff715db402d767b0e8">More...</a><br /></td></tr>
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Variables</h2></td></tr>
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const uint8_t </td><td class="memItemRight" valign="bottom"><b>b_m16_interleave</b> [] = { 0, 49, 49, 41, 90, 27, 117, 10 }</td></tr>
<tr class="separator:gadc654138105ff193df0fbc7a0c21806c"><td class="memSeparator" colspan="2"> </td></tr>
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<a name="details" id="details"></a><h2 class="groupheader">Detailed Description</h2>
<p>Fast 8 and 16-bit approximations of sin(x) and cos(x). </p>
<p>Don't use these approximations for calculating the trajectory of a rocket to Mars, but they're great for art projects and LED displays.</p>
<p>On Arduino/AVR, the 16-bit approximation is more than 10X faster than floating point sin(x) and cos(x), while the 8-bit approximation is more than 20X faster. </p>
<h2 class="groupheader">Function Documentation</h2>
<a class="anchor" id="ga056952ebed39f55880bb353857b47075"></a>
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">LIB8STATIC int16_t cos16 </td>
<td>(</td>
<td class="paramtype">uint16_t </td>
<td class="paramname"><em>theta</em></td><td>)</td>
<td></td>
</tr>
</table>
</div><div class="memdoc">
<p>Fast 16-bit approximation of cos(x). </p>
<p>This approximation never varies more than 0.69% from the floating point value you'd get by doing </p><pre class="fragment">float s = cos(x) * 32767.0;
</pre><dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramname">theta</td><td>input angle from 0-65535 </td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>sin of theta, value between -32767 to 32767. </dd></dl>
<p>Definition at line <a class="el" href="trig8_8h_source.html#l00120">120</a> of file <a class="el" href="trig8_8h_source.html">trig8.h</a>.</p>
</div>
</div>
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<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">LIB8STATIC uint8_t cos8 </td>
<td>(</td>
<td class="paramtype">uint8_t </td>
<td class="paramname"><em>theta</em></td><td>)</td>
<td></td>
</tr>
</table>
</div><div class="memdoc">
<p>Fast 8-bit approximation of cos(x). </p>
<p>This approximation never varies more than 2% from the floating point value you'd get by doing </p><pre class="fragment">float s = (cos(x) * 128.0) + 128;
</pre><dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramname">theta</td><td>input angle from 0-255 </td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>sin of theta, value between 0 and 255 </dd></dl>
<p>Definition at line <a class="el" href="trig8_8h_source.html#l00253">253</a> of file <a class="el" href="trig8_8h_source.html">trig8.h</a>.</p>
</div>
</div>
<a class="anchor" id="ga660ff60bfc5116525e50187de72009fc"></a>
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">LIB8STATIC int16_t sin16_avr </td>
<td>(</td>
<td class="paramtype">uint16_t </td>
<td class="paramname"><em>theta</em></td><td>)</td>
<td></td>
</tr>
</table>
</div><div class="memdoc">
<p>Fast 16-bit approximation of sin(x). </p>
<p>This approximation never varies more than 0.69% from the floating point value you'd get by doing </p><pre class="fragment">float s = sin(x) * 32767.0;
</pre><dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramname">theta</td><td>input angle from 0-65535 </td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>sin of theta, value between -32767 to 32767. </dd></dl>
<p>Definition at line <a class="el" href="trig8_8h_source.html#l00030">30</a> of file <a class="el" href="trig8_8h_source.html">trig8.h</a>.</p>
</div>
</div>
<a class="anchor" id="ga0890962cb06b267617f4b06d7e9be5eb"></a>
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">LIB8STATIC int16_t sin16_C </td>
<td>(</td>
<td class="paramtype">uint16_t </td>
<td class="paramname"><em>theta</em></td><td>)</td>
<td></td>
</tr>
</table>
</div><div class="memdoc">
<p>Fast 16-bit approximation of sin(x). </p>
<p>This approximation never varies more than 0.69% from the floating point value you'd get by doing </p><pre class="fragment">float s = sin(x) * 32767.0;
</pre><dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramname">theta</td><td>input angle from 0-65535 </td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>sin of theta, value between -32767 to 32767. </dd></dl>
<p>Definition at line <a class="el" href="trig8_8h_source.html#l00088">88</a> of file <a class="el" href="trig8_8h_source.html">trig8.h</a>.</p>
</div>
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<a class="anchor" id="ga6aa1f993cbbc427d80da1ee2ccca86e7"></a>
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">LIB8STATIC uint8_t sin8_avr </td>
<td>(</td>
<td class="paramtype">uint8_t </td>
<td class="paramname"><em>theta</em></td><td>)</td>
<td></td>
</tr>
</table>
</div><div class="memdoc">
<p>Fast 8-bit approximation of sin(x). </p>
<p>This approximation never varies more than 2% from the floating point value you'd get by doing </p><pre class="fragment">float s = (sin(x) * 128.0) + 128;
</pre><dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramname">theta</td><td>input angle from 0-255 </td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>sin of theta, value between 0 and 255 </dd></dl>
<p>Definition at line <a class="el" href="trig8_8h_source.html#l00159">159</a> of file <a class="el" href="trig8_8h_source.html">trig8.h</a>.</p>
</div>
</div>
<a class="anchor" id="ga46933a9b42921c6605588268d11f7c1e"></a>
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">LIB8STATIC uint8_t sin8_C </td>
<td>(</td>
<td class="paramtype">uint8_t </td>
<td class="paramname"><em>theta</em></td><td>)</td>
<td></td>
</tr>
</table>
</div><div class="memdoc">
<p>Fast 8-bit approximation of sin(x). </p>
<p>This approximation never varies more than 2% from the floating point value you'd get by doing </p><pre class="fragment">float s = (sin(x) * 128.0) + 128;
</pre><dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramname">theta</td><td>input angle from 0-255 </td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>sin of theta, value between 0 and 255 </dd></dl>
<p>Definition at line <a class="el" href="trig8_8h_source.html#l00217">217</a> of file <a class="el" href="trig8_8h_source.html">trig8.h</a>.</p>
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