Changeset - r28190:29617a715136
[Not reviewed]
master
0 1 0
Peter Nelson - 12 months ago 2023-11-28 00:05:30
peter1138@openttd.org
Codechange: Template input buffer type in audio mixer. (#11505)

This reduces code duplication.
1 file changed with 12 insertions and 44 deletions:
0 comments (0 inline, 0 general)
src/mixer.cpp
Show inline comments
 
@@ -63,13 +63,17 @@ static int RateConversion(T *b, int frac
 
	return ((b[0] * ((1 << 16) - frac_pos)) + (b[1] * frac_pos)) >> 16;
 
}
 

	
 
template <typename T>
 
static void mix_int16(MixerChannel *sc, int16_t *buffer, uint samples, uint8_t effect_vol)
 
{
 
	/* Shift required to get sample value into range for the data type. */
 
	const uint SHIFT = sizeof(T) * CHAR_BIT;
 

	
 
	if (samples > sc->samples_left) samples = sc->samples_left;
 
	sc->samples_left -= samples;
 
	assert(samples > 0);
 

	
 
	const int16_t *b = (const int16_t *)sc->memory + sc->pos;
 
	const T *b = (const T *)sc->memory + sc->pos;
 
	uint32_t frac_pos = sc->frac_pos;
 
	uint32_t frac_speed = sc->frac_speed;
 
	int volume_left = sc->volume_left * effect_vol / 255;
 
@@ -78,16 +82,16 @@ static void mix_int16(MixerChannel *sc, 
 
	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);
 
			buffer[0] = Clamp(buffer[0] + (*b * volume_left  >> SHIFT), -MAX_VOLUME, MAX_VOLUME);
 
			buffer[1] = Clamp(buffer[1] + (*b * volume_right >> SHIFT), -MAX_VOLUME, MAX_VOLUME);
 
			b++;
 
			buffer += 2;
 
		} while (--samples > 0);
 
	} else {
 
		do {
 
			int data = RateConversion(b, frac_pos);
 
			buffer[0] = Clamp(buffer[0] + (data * volume_left  >> 16), -MAX_VOLUME, MAX_VOLUME);
 
			buffer[1] = Clamp(buffer[1] + (data * volume_right >> 16), -MAX_VOLUME, MAX_VOLUME);
 
			buffer[0] = Clamp(buffer[0] + (data * volume_left  >> SHIFT), -MAX_VOLUME, MAX_VOLUME);
 
			buffer[1] = Clamp(buffer[1] + (data * volume_right >> SHIFT), -MAX_VOLUME, MAX_VOLUME);
 
			buffer += 2;
 
			frac_pos += frac_speed;
 
			b += frac_pos >> 16;
 
@@ -96,43 +100,7 @@ static void mix_int16(MixerChannel *sc, 
 
	}
 

	
 
	sc->frac_pos = frac_pos;
 
	sc->pos = b - (const int16_t *)sc->memory;
 
}
 

	
 
static void mix_int8_to_int16(MixerChannel *sc, int16_t *buffer, uint samples, uint8_t effect_vol)
 
{
 
	if (samples > sc->samples_left) samples = sc->samples_left;
 
	sc->samples_left -= samples;
 
	assert(samples > 0);
 

	
 
	const int8_t *b = sc->memory + sc->pos;
 
	uint32_t frac_pos = sc->frac_pos;
 
	uint32_t frac_speed = sc->frac_speed;
 
	int volume_left = sc->volume_left * effect_vol / 255;
 
	int volume_right = sc->volume_right * effect_vol / 255;
 

	
 
	if (frac_speed == 0x10000) {
 
		/* Special case when frac_speed is 0x10000 */
 
		do {
 
			buffer[0] = Clamp(buffer[0] + (*b * volume_left  >> 8), -MAX_VOLUME, MAX_VOLUME);
 
			buffer[1] = Clamp(buffer[1] + (*b * volume_right >> 8), -MAX_VOLUME, MAX_VOLUME);
 
			b++;
 
			buffer += 2;
 
		} while (--samples > 0);
 
	} else {
 
		do {
 
			int data = RateConversion(b, frac_pos);
 
			buffer[0] = Clamp(buffer[0] + (data * volume_left  >> 8), -MAX_VOLUME, MAX_VOLUME);
 
			buffer[1] = Clamp(buffer[1] + (data * volume_right >> 8), -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 - sc->memory;
 
	sc->pos = b - (const T *)sc->memory;
 
}
 

	
 
static void MxCloseChannel(uint8_t channel_index)
 
@@ -172,9 +140,9 @@ void MxMixSamples(void *buffer, uint sam
 
	for (uint8_t idx : SetBitIterator(active)) {
 
		MixerChannel *mc = &_channels[idx];
 
		if (mc->is16bit) {
 
			mix_int16(mc, (int16_t*)buffer, samples, effect_vol);
 
			mix_int16<int16_t>(mc, (int16_t*)buffer, samples, effect_vol);
 
		} else {
 
			mix_int8_to_int16(mc, (int16_t*)buffer, samples, effect_vol);
 
			mix_int16<int8_t>(mc, (int16_t*)buffer, samples, effect_vol);
 
		}
 
		if (mc->samples_left == 0) MxCloseChannel(idx);
 
	}
0 comments (0 inline, 0 general)