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(svn r17140) -Change: allow higher sample rate and higher quality samples. Based on work by orudge.

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This commit is contained in:
rubidium
2009-08-09 23:04:08 +00:00
parent 9ee2a66c86
commit 8e058c2d27
7 changed files with 80 additions and 21 deletions
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55
src/mixer.cpp
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@@ -21,6 +21,8 @@ struct MixerChannel {
/* Mixing volume */
int volume_left;
int volume_right;
bool is16bit;
};
static MixerChannel _channels[8];
@@ -34,6 +36,46 @@ static uint32 _play_rate = 11025;
*/
static const int MAX_VOLUME = 128 * 128;
static void mix_int16(MixerChannel *sc, int16 *buffer, uint samples)
{
int16 *b;
uint32 frac_pos;
uint32 frac_speed;
int volume_left;
int volume_right;
if (samples > sc->samples_left) samples = sc->samples_left;
sc->samples_left -= samples;
assert(samples > 0);
b = (int16*)sc->memory + sc->pos;
frac_pos = sc->frac_pos;
frac_speed = sc->frac_speed;
volume_left = sc->volume_left;
volume_right = sc->volume_right;
if (frac_speed == 0x10000) {
/* Special case when frac_speed is 0x10000 */
do {
buffer[0] = Clamp(buffer[0] + (*b * volume_left >> 16), -MAX_VOLUME, MAX_VOLUME);
buffer[1] = Clamp(buffer[1] + (*b * volume_right >> 16), -MAX_VOLUME, MAX_VOLUME);
b++;
buffer += 2;
} while (--samples > 0);
} else {
do {
buffer[0] = Clamp(buffer[0] + (*b * volume_left >> 16), -MAX_VOLUME, MAX_VOLUME);
buffer[1] = Clamp(buffer[1] + (*b * volume_right >> 16), -MAX_VOLUME, MAX_VOLUME);
buffer += 2;
frac_pos += frac_speed;
b += frac_pos >> 16;
frac_pos &= 0xffff;
} while (--samples > 0);
}
sc->frac_pos = frac_pos;
sc->pos = b - (int16*)sc->memory;
}
static void mix_int8_to_int16(MixerChannel *sc, int16 *buffer, uint samples)
{
@@ -93,7 +135,11 @@ void MxMixSamples(void *buffer, uint samples)
/* Mix each channel */
for (mc = _channels; mc != endof(_channels); mc++) {
if (mc->active) {
mix_int8_to_int16(mc, (int16*)buffer, samples);
if (mc->is16bit) {
mix_int16(mc, (int16*)buffer, samples);
} else {
mix_int8_to_int16(mc, (int16*)buffer, samples);
}
if (mc->samples_left == 0) MxCloseChannel(mc);
}
}
@@ -110,7 +156,7 @@ MixerChannel *MxAllocateChannel()
return NULL;
}
void MxSetChannelRawSrc(MixerChannel *mc, int8 *mem, size_t size, uint rate)
void MxSetChannelRawSrc(MixerChannel *mc, int8 *mem, size_t size, uint rate, bool is16bit)
{
mc->memory = mem;
mc->frac_pos = 0;
@@ -124,7 +170,10 @@ void MxSetChannelRawSrc(MixerChannel *mc, int8 *mem, size_t size, uint rate)
rate = (rate >> 1) + 1;
}
mc->samples_left = (uint)size * _play_rate / rate;
int div = is16bit ? 2 : 1;
mc->samples_left = (uint)size * _play_rate / rate / div;
mc->is16bit = is16bit;
}
void MxSetChannelVolume(MixerChannel *mc, uint left, uint right)