prosperon/source/engine/dsp.c

115 lines
2.3 KiB
C

#include "dsp.h"
#include "sound.h"
#include "limits.h"
#include "math.h"
#define PI 3.14159265
void am_mod(short *a, short *b, short *c, int n)
{
for (int i = 0; i < n; i++) {
c[i] = (a[i]*b[i])>>15;
}
}
static struct wav make_wav(float freq, int sr, int ch) {
struct wav new;
new.ch = ch;
new.samplerate = sr;
new.frames = sr/freq;
new.data = calloc(new.frames*new.ch, sizeof(short));
return new;
}
struct wav gen_sine(float amp, float freq, int sr, int ch)
{
struct wav new = make_wav(freq, sr, ch);
if (amp > 1) amp = 1;
if (amp < 0) amp = 0;
short samp = amp*SHRT_MAX;
short *data = (short*)new.data;
for (int i = 0; i < new.frames; i++) {
short val = samp * sin(2*PI*((float)i / new.frames));
for (int j = 0; j < new.ch; j++) {
data[i*new.ch+j] = val;
printf("Element %i gets val %i.\n", i*new.frames+j, val);
}
}
return new;
}
struct wav gen_square(float amp, float freq, int sr, int ch)
{
struct wav new = make_wav(freq, sr, ch);
int crossover = new.frames/2;
if (amp > 1) amp = 1;
if (amp < 0) amp = 0;
short samp = amp * SHRT_MAX;
short *data = (short*)new.data;
for (int i = 0; i < new.frames; i++) {
short val = -2 * floor(2 * i / new.frames) + 1;
for (int j = 0; j < new.ch; j++) {
data[i*new.frames+j] = val;
}
}
return new;
}
struct wav gen_triangle(float amp, float freq, int sr, int ch)
{
struct wav new = make_wav(freq, sr, ch);
if (amp > 1) amp = 1;
if (amp < 0) amp = 0;
short *data = (short*)new.data;
for (int i = 0; i < new.frames; i++) {
short val = 2 * abs( (i/new.frames) - floor( (i/new.frames) + 0.5));
for (int j = 0; j < new.ch; j++) {
data[i+j] = val;
}
}
}
struct wav gen_saw(float amp, float freq, int sr, int ch)
{
struct wav new = make_wav(freq, sr, ch);
if (amp > 1) amp = 1;
if (amp < 0) amp = 0;
short samp = amp*SHRT_MAX;
short *data = (short*)new.data;
for (int i = 0; i < new.frames; i++) {
short val = samp * 2 * i/sr - samp;
for (int j = 0; j < new.ch; j++) {
data[i+j] = val;
}
}
}
void make_dsp_filter()
{
}
void dsp_filter(short *in, short *out, int samples, struct dsp_delay *d)
{
}