1 /*
2 * $Id: patest_maxsines.c,v 1.4.4.1 2003/04/10 23:09:40 philburk Exp $
3 * patest_maxsines.c
4 * How many sine waves can we calculate and play in less than 80% CPU Load.
5 *
6 * Authors:
7 * Ross Bencina <rossb@audiomulch.com>
8 * Phil Burk <philburk@softsynth.com>
9 *
10 * This program uses the PortAudio Portable Audio Library.
11 * For more information see: http://www.audiomulch.com/portaudio/
12 * Copyright (c) 1999-2000 Ross Bencina and Phil Burk
13 *
14 * Permission is hereby granted, free of charge, to any person obtaining
15 * a copy of this software and associated documentation files
16 * (the "Software"), to deal in the Software without restriction,
17 * including without limitation the rights to use, copy, modify, merge,
18 * publish, distribute, sublicense, and/or sell copies of the Software,
19 * and to permit persons to whom the Software is furnished to do so,
20 * subject to the following conditions:
21 *
22 * The above copyright notice and this permission notice shall be
23 * included in all copies or substantial portions of the Software.
24 *
25 * Any person wishing to distribute modifications to the Software is
26 * requested to send the modifications to the original developer so that
27 * they can be incorporated into the canonical version.
28 *
29 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
30 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
31 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
32 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
33 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
34 * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
35 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
36 *
37 */
38 #include <stdio.h>
39 #include <math.h>
40 #include "portaudio.h"
41
42 #define MAX_SINES (500)
43 #define MAX_USAGE (0.8)
44 #define SAMPLE_RATE (44100)
45 #define FREQ_TO_PHASE_INC(freq) (freq/(float)SAMPLE_RATE)
46
47 #define MIN_PHASE_INC FREQ_TO_PHASE_INC(200.0f)
48 #define MAX_PHASE_INC (MIN_PHASE_INC * (1 << 5))
49
50 #define FRAMES_PER_BUFFER (512)
51 #ifndef M_PI
52 #define M_PI (3.14159265)
53 #endif
54 #define TWOPI (M_PI * 2.0)
55
56 #define TABLE_SIZE (512)
57
58 typedef struct paTestData
59 {
60 int numSines;
61 float sine[TABLE_SIZE + 1]; /* add one for guard point for interpolation */
62 float phases[MAX_SINES];
63 }
64 paTestData;
65
66 /* Convert phase between and 1.0 to sine value
67 * using linear interpolation.
68 */
69 float LookupSine( paTestData *data, float phase );
LookupSine(paTestData * data,float phase)70 float LookupSine( paTestData *data, float phase )
71 {
72 float fIndex = phase*TABLE_SIZE;
73 int index = (int) fIndex;
74 float fract = fIndex - index;
75 float lo = data->sine[index];
76 float hi = data->sine[index+1];
77 float val = lo + fract*(hi-lo);
78 return val;
79 }
80
81 /* This routine will be called by the PortAudio engine when audio is needed.
82 ** It may called at interrupt level on some machines so don't do anything
83 ** that could mess up the system like calling malloc() or free().
84 */
patestCallback(void * inputBuffer,void * outputBuffer,unsigned long framesPerBuffer,PaTimestamp outTime,void * userData)85 static int patestCallback( void *inputBuffer, void *outputBuffer,
86 unsigned long framesPerBuffer,
87 PaTimestamp outTime, void *userData )
88 {
89 paTestData *data = (paTestData*)userData;
90 float *out = (float*)outputBuffer;
91 float outSample;
92 float scaler;
93 int numForScale;
94 unsigned long i;
95 int j;
96 int finished = 0;
97 (void) outTime; /* Prevent unused variable warnings. */
98 (void) inputBuffer;
99
100 /* Detemine amplitude scaling factor */
101 numForScale = data->numSines;
102 if( numForScale < 8 ) numForScale = 8; /* prevent pops at beginning */
103 scaler = 1.0f / numForScale;
104
105 for( i=0; i<framesPerBuffer; i++ )
106 {
107 float output = 0.0;
108 float phaseInc = MIN_PHASE_INC;
109 float phase;
110 for( j=0; j<data->numSines; j++ )
111 {
112 /* Advance phase of next oscillator. */
113 phase = data->phases[j];
114 phase += phaseInc;
115 if( phase >= 1.0 ) phase -= 1.0;
116
117 output += LookupSine(data, phase);
118 data->phases[j] = phase;
119
120 phaseInc *= 1.02f;
121 if( phaseInc > MAX_PHASE_INC ) phaseInc = MIN_PHASE_INC;
122 }
123
124 outSample = (float) (output * scaler);
125 *out++ = outSample; /* Left */
126 *out++ = outSample; /* Right */
127 }
128 return finished;
129 }
130
131 /*******************************************************************/
132 int main(void);
main(void)133 int main(void)
134 {
135 int i;
136 PortAudioStream *stream;
137 PaError err;
138 paTestData data = {0};
139 double load;
140 printf("PortAudio Test: output sine wave. SR = %d, BufSize = %d\n", SAMPLE_RATE, FRAMES_PER_BUFFER);
141
142 /* initialise sinusoidal wavetable */
143 for( i=0; i<TABLE_SIZE; i++ )
144 {
145 data.sine[i] = (float) sin( ((double)i/(double)TABLE_SIZE) * M_PI * 2. );
146 }
147 data.sine[TABLE_SIZE] = data.sine[0]; /* set guard point */
148
149 err = Pa_Initialize();
150 if( err != paNoError ) goto error;
151 err = Pa_OpenStream(
152 &stream,
153 paNoDevice,
154 0, /* no input */
155 paFloat32,
156 NULL,
157 Pa_GetDefaultOutputDeviceID(), /* default output device */
158 2, /* stereo output */
159 paFloat32, /* 32 bit floating point output */
160 NULL,
161 SAMPLE_RATE,
162 FRAMES_PER_BUFFER,
163 0, /* number of buffers, if zero then use default minimum */
164 paClipOff, /* we won't output out of range samples so don't bother clipping them */
165 patestCallback,
166 &data );
167 if( err != paNoError ) goto error;
168 err = Pa_StartStream( stream );
169 if( err != paNoError ) goto error;
170
171 /* Play an increasing number of sine waves until we hit MAX_USAGE */
172 do
173 {
174 data.numSines++;
175 Pa_Sleep( 200 );
176
177 load = Pa_GetCPULoad( stream );
178 printf("numSines = %d, CPU load = %f\n", data.numSines, load );
179 fflush( stdout );
180 }
181 while( (load < MAX_USAGE) && (data.numSines < MAX_SINES) );
182
183 printf("Press ENTER to stop.\n" ); fflush(stdout);
184 getchar();
185
186 printf("CPU load = %f\n", Pa_GetCPULoad( stream ) );
187 err = Pa_StopStream( stream );
188 if( err != paNoError ) goto error;
189 err = Pa_CloseStream( stream );
190 if( err != paNoError ) goto error;
191 Pa_Terminate();
192 printf("Test finished.\n");
193 fflush( stdout );
194 return err;
195 error:
196 Pa_Terminate();
197 fprintf( stderr, "An error occured while using the portaudio stream\n" );
198 fprintf( stderr, "Error number: %d\n", err );
199 fprintf( stderr, "Error message: %s\n", Pa_GetErrorText( err ) );
200 return err;
201 }
202