97 lines
2.1 KiB
C
97 lines
2.1 KiB
C
#include "dsp.h"
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#include "sound.h"
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#include "limits.h"
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#include "math.h"
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#define PI 3.14159265
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void am_mod(short *a, short *b, short *c, int n)
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{
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for (int i = 0; i < n; i++) {
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c[i] = (a[i]*b[i])>>15;
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}
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}
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static struct wav make_wav(float freq, int sr, int ch) {
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struct wav new;
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new.ch = ch;
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new.samplerate = sr;
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new.frames = sr/freq;
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new.data = calloc(new.frames*new.ch, sizeof(short));
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return new;
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}
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struct wav gen_sine(float amp, float freq, int sr, int ch)
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{
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struct wav new = make_wav(freq, sr, ch);
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if (amp > 1) amp = 1;
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if (amp < 0) amp = 0;
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short samp = amp*SHRT_MAX;
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short *data = (short*)new.data;
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for (int i = 0; i < new.frames; i++) {
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short val = amp * sin(2*PI*((float)i / new.frames));
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for (int j = 0; j < new.ch; j++) {
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data[i+j] = val;
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}
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}
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return new;
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}
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struct wav gen_square(float amp, float freq, int sr, int ch)
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{
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struct wav new = make_wav(freq, sr, ch);
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int crossover = new.frames/2;
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if (amp > 1) amp = 1;
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if (amp < 0) amp = 0;
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short samp = amp * SHRT_MAX;
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short *data = (short*)new.data;
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for (int i = 0; i < new.frames; i++) {
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short val = -2 * floor(2 * i / new.frames) + 1;
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for (int j = 0; j < new.ch; j++) {
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data[i+j] = val;
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}
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}
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return new;
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}
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struct wav gen_triangle(float amp, float freq, int sr, int ch)
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{
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struct wav new = make_wav(freq, sr, ch);
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if (amp > 1) amp = 1;
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if (amp < 0) amp = 0;
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for (int i = 0; i < new.frames; i++) {
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short val = 2 * abs( (i/new.frames) - floor( (i/new.frames) + 0.5));
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for (int j = 0; j < new.ch; j++) {
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new.data[i+j] = val;
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}
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}
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}
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struct wav gen_saw(float amp, float freq, int sr, int ch)
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{
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struct wav new = make_wav(freq, sr, ch);
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if (amp > 1) amp = 1;
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if (amp < 0) amp = 0;
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for (int i = 0; i < new.frames; i++) {
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short val = 2 * ( (i/new.frames) - floor( (0.5 + (i/new.frames))));
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for (int j = 0; j < new.ch; j++) {
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new.data[i+j] = val;
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}
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}
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} |