diff options
Diffstat (limited to 'src/channel.c')
| -rw-r--r-- | src/channel.c | 33 |
1 files changed, 25 insertions, 8 deletions
diff --git a/src/channel.c b/src/channel.c index 2fd0324..a29e7f7 100644 --- a/src/channel.c +++ b/src/channel.c @@ -1,5 +1,6 @@ #include <stdlib.h> #include <string.h> +#include <math.h> #include <plibsys.h> #include "channel.h" @@ -64,6 +65,15 @@ void channel_set_pan(struct channel_t *chan, float pan_left, float pan_right) } +#define QUARTER_PI 0.785397 +static void pan_gain(float *gain_l, float *gain_r, float pan) +{ + float theta = (QUARTER_PI * pan) + QUARTER_PI; /* 0-PI/2 */ + *gain_l = cos(theta); + *gain_r = sin(theta); +} + + void channel_get_next_sample(float *left, float *right, struct channel_t *chan) { bool active = p_atomic_int_get(&(chan->active)); @@ -82,17 +92,24 @@ void channel_get_next_sample(float *left, float *right, struct channel_t *chan) return; } - float l, r; + float volume = ((float)p_atomic_int_get(&(chan->volume)))/255; - l = chan->sound.left[chan->pos]; - if (chan->sound.mono) - r = l; - else + if (chan->sound.mono) { + float x = chan->sound.left[chan->pos]; + float pan = ((float)p_atomic_int_get(&(chan->pan_left)))/128; + float gain_l, gain_r; + pan_gain(&gain_l, &gain_r, pan); + *left = volume * gain_l * x; + *right = volume * gain_r * x; + } + else { + float l, r; + l = chan->sound.left[chan->pos]; r = chan->sound.right[chan->pos]; + *left = volume * l; + *right = volume * r; + } - 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) { |