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#include <stdlib.h>
#include <string.h>
#include <plibsys.h>
#include "channel.h"
void channel_init(struct channel_t *chan)
{
chan->active = false;
chan->paused = false;
chan->volume = 255;
chan->pan_left = -128;
chan->pan_right = 128;
chan->sound_mutex = p_mutex_new();
chan->sound.left = NULL;
chan->sound.right = NULL;
chan->pos = 0;
}
void channel_reset(struct channel_t *chan)
{
p_atomic_int_set(&(chan->paused), false);
p_atomic_int_set(&(chan->volume), 255);
p_atomic_int_set(&(chan->pan_left), -128);
p_atomic_int_set(&(chan->pan_right), 128);
chan->pos = 0;
p_atomic_int_set(&(chan->active), false);
}
void channel_pause(struct channel_t *chan)
{
p_atomic_int_set(&(chan->paused), true);
}
void channel_resume(struct channel_t *chan)
{
p_atomic_int_set(&(chan->paused), false);
}
void channel_set_volume(struct channel_t *chan, float volume)
{
if (volume > 1.0f) volume = 1.0f;
if (volume < 0.0f) volume = 0.0f;
p_atomic_int_set(&(chan->volume), 255*volume);
}
void channel_set_pan(struct channel_t *chan, float pan_left, float pan_right)
{
if (pan_left > 1.0f) pan_left = 1.0f;
if (pan_left < -1.0f) pan_left = -1.0f;
if (pan_right > 1.0f) pan_right = 1.0f;
if (pan_right < -1.0f) pan_right = -1.0f;
p_atomic_int_set(&(chan->pan_left), 128*pan_left);
p_atomic_int_set(&(chan->pan_right), 128*pan_right);
}
void channel_get_next_sample(float *left, float *right, struct channel_t *chan)
{
bool active = p_atomic_int_get(&(chan->active));
bool paused = p_atomic_int_get(&(chan->paused));
if (!active || paused) {
/* skip this channel */
*left = 0;
*right = 0;
return;
}
if (!p_mutex_trylock(chan->sound_mutex)) {
/* can't lock mutex, skip */
*left = 0;
*right = 0;
return;
}
float l, r;
l = chan->sound.left[chan->pos];
if (chan->sound.mono)
r = l;
else
r = chan->sound.right[chan->pos];
float volume = ((float)p_atomic_int_get(&(chan->active)))/255;
*left = volume * l;
*right = volume * r;
chan->pos += 1;
if (chan->pos >= chan->sound.len) {
channel_reset(chan);
}
p_mutex_unlock(chan->sound_mutex);
}
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