diff options
Diffstat (limited to 'src/mixer.cpp')
-rw-r--r-- | src/mixer.cpp | 55 |
1 files changed, 52 insertions, 3 deletions
diff --git a/src/mixer.cpp b/src/mixer.cpp index cf8b30c9a..5a8370df8 100644 --- a/src/mixer.cpp +++ b/src/mixer.cpp @@ -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) |