ref: 7adfd4ca6b951bcc17d3c636bb810876c159950a
dir: prismriver/p-utils.c
#include <u.h>
#include <libc.h>
#include "prismriver.h"
#include "p-internal.h"
enum
{
C,
Db, // C#
D,
Eb, // D#
E,
F,
Gb, // F#
G,
Ab, // G#
A,
Bb, // A#
B
};
const double equaltemperament[] =
{
[C] = 16.35,
[Db] = 17.32,
[D] = 18.35,
[Eb] = 19.45,
[E] = 20.60,
[F] = 21.83,
[Gb] = 23.12,
[G] = 24.50,
[Ab] = 25.96,
[A] = 27.50,
[Bb] = 29.14,
[B] = 30.87
};
double
pitch(uint n, int o)
{
return equaltemperament[n % 12] * pow(2, o + n/12);
}
ulong /* Duration (seconds) to samples */
d2s(double d)
{
return d * SAMPLE_RATE;
}
double /* Samples to duration (seconds) */
s2d(ulong s)
{
return (double)s / SAMPLE_RATE;
}