1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
|
<HTML>
<HEAD>
<TITLE>The Synthesis ToolKit in C++ (STK)</TITLE>
<LINK HREF="doxygen.css" REL="stylesheet" TYPE="text/css">
</HEAD>
<BODY BGCOLOR="#FFFFFF">
<CENTER>
<img src="princeton.gif"> <img src="ccrma.gif"> <img src="mcgill.gif"><P>
<a class="qindex" href="index.html">Home</a> <a class="qindex" href="information.html">Information</a> <a class="qindex" href="classes.html">Classes</a> <a class="qindex" href="download.html">Download</a> <a class="qindex" href="usage.html">Usage</a> <a class="qindex" href="maillist.html">Mail List</a> <a class="qindex" href="system.html">Requirements</a> <a class="qindex" href="links.html">Links</a> <a class="qindex" href="faq.html">FAQ</a> <a class="qindex" href="tutorial.html">Tutorial</a></CENTER>
<HR>
<!-- Generated by Doxygen 1.6.2 -->
<div class="navpath"><a class="el" href="dir_221deb9bdff892d63ed1e409450a60d2.html">include</a>
</div>
<div class="contents">
<h1>Blit.h</h1><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="preprocessor">#ifndef STK_BLIT_H</span>
<a name="l00002"></a>00002 <span class="preprocessor"></span><span class="preprocessor">#define STK_BLIT_H</span>
<a name="l00003"></a>00003 <span class="preprocessor"></span>
<a name="l00004"></a>00004 <span class="preprocessor">#include "Generator.h"</span>
<a name="l00005"></a>00005 <span class="preprocessor">#include <cmath></span>
<a name="l00006"></a>00006 <span class="preprocessor">#include <limits></span>
<a name="l00007"></a>00007
<a name="l00008"></a>00008 <span class="keyword">namespace </span>stk {
<a name="l00009"></a>00009
<a name="l00010"></a>00010 <span class="comment">/***************************************************/</span>
<a name="l00031"></a>00031 <span class="comment">/***************************************************/</span>
<a name="l00032"></a>00032
<a name="l00033"></a><a class="code" href="classstk_1_1Blit.html">00033</a> <span class="keyword">class </span><a class="code" href="classstk_1_1Blit.html" title="STK band-limited impulse train class.">Blit</a>: <span class="keyword">public</span> <a class="code" href="classstk_1_1Generator.html" title="STK abstract unit generator parent class.">Generator</a>
<a name="l00034"></a>00034 {
<a name="l00035"></a>00035 <span class="keyword">public</span>:
<a name="l00037"></a>00037 <a class="code" href="classstk_1_1Blit.html#a63c5e6dca28aa3b3c01808e049f3da33" title="Default constructor that initializes BLIT frequency to 220 Hz.">Blit</a>( StkFloat frequency = 220.0 );
<a name="l00038"></a>00038
<a name="l00040"></a>00040 <a class="code" href="classstk_1_1Blit.html#abed25206cc6cdb5fa8d667e7db0056a9" title="Class destructor.">~Blit</a>();
<a name="l00041"></a>00041
<a name="l00043"></a>00043 <span class="keywordtype">void</span> <a class="code" href="classstk_1_1Blit.html#abbe50319cd6ed762c15e148a8abb4920" title="Resets the oscillator state and phase to 0.">reset</a>();
<a name="l00044"></a>00044
<a name="l00046"></a>00046
<a name="l00049"></a><a class="code" href="classstk_1_1Blit.html#a58e2197cedfc366145b729256bf365cb">00049</a> <span class="keywordtype">void</span> <a class="code" href="classstk_1_1Blit.html#a58e2197cedfc366145b729256bf365cb" title="Set the phase of the signal.">setPhase</a>( StkFloat phase ) { phase_ = PI * phase; };
<a name="l00050"></a>00050
<a name="l00052"></a>00052
<a name="l00055"></a><a class="code" href="classstk_1_1Blit.html#a01fb40970e8905e47b7f39a1fb01589f">00055</a> StkFloat <a class="code" href="classstk_1_1Blit.html#a01fb40970e8905e47b7f39a1fb01589f" title="Get the current phase of the signal.">getPhase</a>()<span class="keyword"> const </span>{ <span class="keywordflow">return</span> phase_ / PI; };
<a name="l00056"></a>00056
<a name="l00058"></a>00058 <span class="keywordtype">void</span> <a class="code" href="classstk_1_1Blit.html#a5571562e489947c4beccc206ecccfbdd" title="Set the impulse train rate in terms of a frequency in Hz.">setFrequency</a>( StkFloat frequency );
<a name="l00059"></a>00059
<a name="l00061"></a>00061
<a name="l00073"></a>00073 <span class="keywordtype">void</span> <a class="code" href="classstk_1_1Blit.html#a5a1fd506ab12ae614afaf0e402d24d30" title="Set the number of harmonics generated in the signal.">setHarmonics</a>( <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> nHarmonics = 0 );
<a name="l00074"></a>00074
<a name="l00076"></a><a class="code" href="classstk_1_1Blit.html#a530af82a27731734af4f4b58bce283de">00076</a> StkFloat <a class="code" href="classstk_1_1Blit.html#a530af82a27731734af4f4b58bce283de" title="Return the last computed output value.">lastOut</a>( <span class="keywordtype">void</span> )<span class="keyword"> const </span>{ <span class="keywordflow">return</span> lastFrame_[0]; };
<a name="l00077"></a>00077
<a name="l00079"></a>00079 StkFloat <a class="code" href="classstk_1_1Blit.html#a528b8dc95499b11d6173cf065d62c717" title="Compute and return one output sample.">tick</a>( <span class="keywordtype">void</span> );
<a name="l00080"></a>00080
<a name="l00082"></a>00082
<a name="l00089"></a>00089 <a class="code" href="classstk_1_1StkFrames.html" title="An STK class to handle vectorized audio data.">StkFrames</a>& <a class="code" href="classstk_1_1Blit.html#a528b8dc95499b11d6173cf065d62c717" title="Compute and return one output sample.">tick</a>( <a class="code" href="classstk_1_1StkFrames.html" title="An STK class to handle vectorized audio data.">StkFrames</a>& frames, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> channel = 0 );
<a name="l00090"></a>00090
<a name="l00091"></a>00091 <span class="keyword">protected</span>:
<a name="l00092"></a>00092
<a name="l00093"></a>00093 <span class="keywordtype">void</span> updateHarmonics( <span class="keywordtype">void</span> );
<a name="l00094"></a>00094
<a name="l00095"></a>00095 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> nHarmonics_;
<a name="l00096"></a>00096 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> m_;
<a name="l00097"></a>00097 StkFloat rate_;
<a name="l00098"></a>00098 StkFloat phase_;
<a name="l00099"></a>00099 StkFloat p_;
<a name="l00100"></a>00100
<a name="l00101"></a>00101 };
<a name="l00102"></a>00102
<a name="l00103"></a><a class="code" href="classstk_1_1Blit.html#a528b8dc95499b11d6173cf065d62c717">00103</a> <span class="keyword">inline</span> StkFloat <a class="code" href="classstk_1_1Blit.html#a528b8dc95499b11d6173cf065d62c717" title="Compute and return one output sample.">Blit :: tick</a>( <span class="keywordtype">void</span> )
<a name="l00104"></a>00104 {
<a name="l00105"></a>00105 <span class="comment">// The code below implements the SincM algorithm of Stilson and</span>
<a name="l00106"></a>00106 <span class="comment">// Smith with an additional scale factor of P / M applied to</span>
<a name="l00107"></a>00107 <span class="comment">// normalize the output.</span>
<a name="l00108"></a>00108
<a name="l00109"></a>00109 <span class="comment">// A fully optimized version of this code would replace the two sin</span>
<a name="l00110"></a>00110 <span class="comment">// calls with a pair of fast sin oscillators, for which stable fast</span>
<a name="l00111"></a>00111 <span class="comment">// two-multiply algorithms are well known. In the spirit of STK,</span>
<a name="l00112"></a>00112 <span class="comment">// which favors clarity over performance, the optimization has not</span>
<a name="l00113"></a>00113 <span class="comment">// been made here.</span>
<a name="l00114"></a>00114
<a name="l00115"></a>00115 <span class="comment">// Avoid a divide by zero at the sinc peak, which has a limiting</span>
<a name="l00116"></a>00116 <span class="comment">// value of 1.0.</span>
<a name="l00117"></a>00117 StkFloat tmp, denominator = sin( phase_ );
<a name="l00118"></a>00118 <span class="keywordflow">if</span> ( denominator <= std::numeric_limits<StkFloat>::epsilon() )
<a name="l00119"></a>00119 tmp = 1.0;
<a name="l00120"></a>00120 <span class="keywordflow">else</span> {
<a name="l00121"></a>00121 tmp = sin( m_ * phase_ );
<a name="l00122"></a>00122 tmp /= m_ * denominator;
<a name="l00123"></a>00123 }
<a name="l00124"></a>00124
<a name="l00125"></a>00125 phase_ += rate_;
<a name="l00126"></a>00126 <span class="keywordflow">if</span> ( phase_ >= PI ) phase_ -= PI;
<a name="l00127"></a>00127
<a name="l00128"></a>00128 lastFrame_[0] = tmp;
<a name="l00129"></a>00129 <span class="keywordflow">return</span> lastFrame_[0];
<a name="l00130"></a>00130 }
<a name="l00131"></a>00131
<a name="l00132"></a><a class="code" href="classstk_1_1Blit.html#a20a3634131ff890641931c1d04df19ad">00132</a> <span class="keyword">inline</span> <a class="code" href="classstk_1_1StkFrames.html" title="An STK class to handle vectorized audio data.">StkFrames</a>& <a class="code" href="classstk_1_1Blit.html#a528b8dc95499b11d6173cf065d62c717" title="Compute and return one output sample.">Blit :: tick</a>( <a class="code" href="classstk_1_1StkFrames.html" title="An STK class to handle vectorized audio data.">StkFrames</a>& frames, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> channel )
<a name="l00133"></a>00133 {
<a name="l00134"></a>00134 <span class="preprocessor">#if defined(_STK_DEBUG_)</span>
<a name="l00135"></a>00135 <span class="preprocessor"></span> <span class="keywordflow">if</span> ( channel >= frames.<a class="code" href="classstk_1_1StkFrames.html#aec7ef9c46675a24111aa6e2fda3ba870" title="Return the number of channels represented by the data.">channels</a>() ) {
<a name="l00136"></a>00136 oStream_ << <span class="stringliteral">"Blit::tick(): channel and StkFrames arguments are incompatible!"</span>;
<a name="l00137"></a>00137 <a class="code" href="classstk_1_1Stk.html#a48ac73a0d8ca28445ba1a054e1f061ff" title="Static function for error reporting and handling using c-strings.">handleError</a>( StkError::FUNCTION_ARGUMENT );
<a name="l00138"></a>00138 }
<a name="l00139"></a>00139 <span class="preprocessor">#endif</span>
<a name="l00140"></a>00140 <span class="preprocessor"></span>
<a name="l00141"></a>00141 StkFloat *samples = &frames[channel];
<a name="l00142"></a>00142 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> hop = frames.<a class="code" href="classstk_1_1StkFrames.html#aec7ef9c46675a24111aa6e2fda3ba870" title="Return the number of channels represented by the data.">channels</a>();
<a name="l00143"></a>00143 <span class="keywordflow">for</span> ( <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> i=0; i<frames.<a class="code" href="classstk_1_1StkFrames.html#a05b1ab6fa750a8221a7d65c30e0cdab9" title="Return the number of sample frames represented by the data.">frames</a>(); i++, samples += hop )
<a name="l00144"></a>00144 *samples = <a class="code" href="classstk_1_1Blit.html#a528b8dc95499b11d6173cf065d62c717" title="Compute and return one output sample.">Blit::tick</a>();
<a name="l00145"></a>00145
<a name="l00146"></a>00146 <span class="keywordflow">return</span> frames;
<a name="l00147"></a>00147 }
<a name="l00148"></a>00148
<a name="l00149"></a>00149 } <span class="comment">// stk namespace</span>
<a name="l00150"></a>00150
<a name="l00151"></a>00151 <span class="preprocessor">#endif</span>
</pre></div></div>
<HR>
<table>
<tr><td><A HREF="http://ccrma.stanford.edu/software/stk/"><I>The Synthesis ToolKit in C++ (STK)</I></A></td></tr>
<tr><td>©1995-2012 Perry R. Cook and Gary P. Scavone. All Rights Reserved.</td></tr>
</table>
</BODY>
</HTML>
|
