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[Core/Sound] optimized Blip Buffer implementation for stereo streams (thanks to David Knight for original idea)

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EkeEke 2016-12-18 23:09:16 +01:00 committed by twinaphex
parent 25626ea251
commit cb2193583b
1 changed files with 12 additions and 34 deletions
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46
core/sound/sn76489.c
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@ -167,45 +167,23 @@ int SN76489_GetContextSize(void)
/* Updates tone amplitude in delta buffer. Call whenever amplitude might have changed. */
INLINE void UpdateToneAmplitude(int i, int time)
{
int delta;
/* left output */
delta = (SN76489.Channel[i][0] * SN76489.ToneFreqPos[i]) - SN76489.ChanOut[i][0];
if (delta != 0)
{
SN76489.ChanOut[i][0] += delta;
blip_add_delta(snd.blips[0][0], time, delta);
}
/* right output */
delta = (SN76489.Channel[i][1] * SN76489.ToneFreqPos[i]) - SN76489.ChanOut[i][1];
if (delta != 0)
{
SN76489.ChanOut[i][1] += delta;
blip_add_delta(snd.blips[0][1], time, delta);
}
/* left & right output */
int delta_l = (SN76489.Channel[i][0] * SN76489.ToneFreqPos[i]) - SN76489.ChanOut[i][0];
int delta_r = (SN76489.Channel[i][1] * SN76489.ToneFreqPos[i]) - SN76489.ChanOut[i][1];
blip_add_delta(snd.blips[0], time, delta_l, delta_r);
SN76489.ChanOut[i][0] += delta_l;
SN76489.ChanOut[i][1] += delta_r;
}
/* Updates noise amplitude in delta buffer. Call whenever amplitude might have changed. */
INLINE void UpdateNoiseAmplitude(int time)
{
int delta;
/* left output */
delta = (SN76489.Channel[3][0] * ( SN76489.NoiseShiftRegister & 0x1 )) - SN76489.ChanOut[3][0];
if (delta != 0)
{
SN76489.ChanOut[3][0] += delta;
blip_add_delta(snd.blips[0][0], time, delta);
}
/* right output */
delta = (SN76489.Channel[3][1] * ( SN76489.NoiseShiftRegister & 0x1 )) - SN76489.ChanOut[3][1];
if (delta != 0)
{
SN76489.ChanOut[3][1] += delta;
blip_add_delta(snd.blips[0][1], time, delta);
}
/* left & right output */
int delta_l = (SN76489.Channel[3][0] * ( SN76489.NoiseShiftRegister & 0x1 )) - SN76489.ChanOut[3][0];
int delta_r = (SN76489.Channel[3][1] * ( SN76489.NoiseShiftRegister & 0x1 )) - SN76489.ChanOut[3][1];
blip_add_delta(snd.blips[0], time, delta_l, delta_r);
SN76489.ChanOut[3][0] += delta_l;
SN76489.ChanOut[3][1] += delta_r;
}
/* Runs tone channel for clock_length clocks */