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13<H1 align="left">AXART_LFO</H1>
14
15<H2>C Specification</H2>
16<DL>
17<dd><pre><CODE>#include &lt;revolution.h&gt;
18#include &lt;revolution/axart.h&gt;</CODE></pre>
19  </dd>
20  <dd>
21<PRE><CODE>typedef struct
22{
23f32         *lfo;           // lfo samples in RAM
24u32         length;         // lfo samples for 1 period
25f32         delta;          // lfo delta per 5ms
26
27u32         sampleIndex;    // lfo sample index
28f32         counter;        // lfo counter
29f32         sample1;        // lfo last sample for interpolation
30f32         sample;         // lfo sample
31f32         output;         // lfo output
32
33} AXART_LFO;</CODE></PRE>
34  </dd>
35</DL>
36
37<H2>Description</H2>
38<P><font face="Courier New">AXART_LFO</font> is a data structure for an LFO. <font face="Courier New">AXART_LFO</font> is used by articulators that modulate volume or pitch. To apply an articulator containing an LFO to an <a href="AXART_SOUND.html"><font face="Courier New">AXART_SOUND</font></a>, the <font face="Courier New">AXART_LFO</font> must be initialized by calling <a href="AXARTInitLfo.html"><font face="Courier New">AXARTInitLfo()</font></a> prior to calling <a href="AXARTAddArticulator.html"><font face="Courier New">AXARTAddArticulator()</font></a>.</P>
39<TABLE border="1" cellpadding="3" cellspacing="0.1">
40  <TBODY>
41    <TR>
42<TD width="120" bgcolor="#cccccc"><EM><STRONG>Data Member</STRONG></EM></TD>
43<TD width="520" bgcolor="#cccccc"><EM><STRONG>Description</STRONG></EM></TD>
44    </TR>
45    <TR>
46<TD width="120"><FONT face="Courier New">f32 *lfo</FONT></TD>
47<TD width="520">Pointer to the first sample of LFO shape in RAM. This parameter is maintained by AXART. Do not write to this parameter.</TD>
48    </TR>
49    <TR>
50<TD width="120"><FONT face="Courier New">u32 length</FONT></TD>
51<TD width="520">Number of samples for the LFO. This parameter is maintained by AXART. Do not write to this parameter.</TD>
52    </TR>
53    <TR>
54<TD width="120"><FONT face="Courier New">f32 delta</FONT></TD>
55<TD width="520">Sample index delta per audio frame. This sets period frequency for the LFO.<BR>delta =&nbsp; Hz * (length / 200).<BR>  The user may change this at any time.</TD>
56    </TR>
57    <TR>
58<TD width="120"><FONT face="Courier New">u32 sampleIndex</FONT></TD>
59<TD width="520">Current sample index for LFO output. This parameter is maintained by AXART. Do not write to this parameter.</TD>
60    </TR>
61    <TR>
62<TD width="120"><FONT face="Courier New">f32 counter</FONT></TD>
63<TD width="520">Running counter for output sample interpolation. Interpolation is linear. This parameter is maintained by AXART. Do not write to this parameter.</TD>
64    </TR>
65    <TR>
66<TD width="120"><FONT face="Courier New">f32 sample1</FONT></TD>
67<TD width="520">Last LFO sample for interpolation. This parameter is maintained by AXART. Do not write to this parameter.</TD>
68    </TR>
69    <TR>
70<TD width="120"><FONT face="Courier New">f32 sample</FONT></TD>
71<TD width="520">Current LFO sample for interpolation. This parameter is maintained by AXART. Do not write to this parameter.</TD>
72    </TR>
73    <TR>
74<TD width="120"><FONT face="Courier New">f32 output</FONT></TD>
75<TD width="520">Output for LFO.&nbsp;This parameter is maintained by AXART. Do not write to this parameter.</TD>
76    </TR>
77  </TBODY>
78</TABLE>
79
80<H2>See Also</H2>
81<P><FONT face="Courier New"><A href="AXARTInitLfo.html">AXARTInitLfo<BR></A><A href="AXARTAddArticulator.html">AXARTAddArticulator<BR></A><A href="AXART_SOUND.html">AXART_SOUND</A></FONT></P>
82
83<H2>Revision History</H2>
84<P>03/01/2006 Initial version.</P>
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