virtualx-engine/servers/audio/effects/audio_effect_chorus.cpp

#include "audio_effect_chorus.h"
#include "servers/audio_server.h"
#include "math_funcs.h"

void AudioEffectChorusInstance::process(const AudioFrame *p_src_frames,AudioFrame *p_dst_frames,int p_frame_count) {

	int todo = p_frame_count;

	while(todo) {

		int to_mix = MIN(todo,256); //can't mix too much

		_process_chunk(p_src_frames,p_dst_frames,to_mix);

		p_src_frames+=to_mix;
		p_dst_frames+=to_mix;

		todo-=to_mix;
	}
}

void AudioEffectChorusInstance::_process_chunk(const AudioFrame *p_src_frames,AudioFrame *p_dst_frames,int p_frame_count) {


	//fill ringbuffer
	for(int i=0;i<p_frame_count;i++) {
		audio_buffer[(buffer_pos+i)&buffer_mask]=p_src_frames[i];
		p_dst_frames[i]=p_src_frames[i]*base->dry;
	}

	float mix_rate = AudioServer::get_singleton()->get_mix_rate();

	/* process voices */
	for (int vc=0;vc<base->voice_count;vc++) {

		AudioEffectChorus::Voice &v=base->voice[vc];


		double time_to_mix=(float)p_frame_count/mix_rate;
		double cycles_to_mix=time_to_mix*v.rate;

		unsigned int local_rb_pos=buffer_pos;
		AudioFrame *dst_buff=p_dst_frames;
		AudioFrame *rb_buff=audio_buffer.ptr();

		double delay_msec=v.delay;
		unsigned int delay_frames=Math::fast_ftoi((delay_msec/1000.0)*mix_rate);
		float max_depth_frames=(v.depth/1000.0)*mix_rate;

		uint64_t local_cycles=cycles[vc];
		uint64_t increment=llrint(cycles_to_mix/(double)p_frame_count*(double)(1<<AudioEffectChorus::CYCLES_FRAC));

		//check the LFO doesnt read ahead of the write pos
		if ((((int)max_depth_frames)+10)>delay_frames) { //10 as some threshold to avoid precision stuff
			delay_frames+=(int)max_depth_frames-delay_frames;
			delay_frames+=10; //threshold to avoid precision stuff

		}



		//low pass filter
		if (v.cutoff==0)
			continue;
		float auxlp=expf(-2.0*Math_PI*v.cutoff/mix_rate);
		float c1=1.0-auxlp;
		float c2=auxlp;
		AudioFrame h=filter_h[vc];
		if (v.cutoff>=AudioEffectChorus::MS_CUTOFF_MAX) {
			c1=1.0; c2=0.0;
		}

		//vol modifier

		AudioFrame vol_modifier=AudioFrame(base->wet,base->wet) * Math::db2linear(v.level);
		vol_modifier.l*=CLAMP( 1.0 - v.pan, 0, 1);
		vol_modifier.r*=CLAMP( 1.0 + v.pan, 0, 1);



		for (int i=0;i<p_frame_count;i++) {

			/** COMPUTE WAVEFORM **/

			float phase=(float)(local_cycles&AudioEffectChorus::CYCLES_MASK)/(float)(1<<AudioEffectChorus::CYCLES_FRAC);

			float wave_delay=sinf(phase*2.0*Math_PI)*max_depth_frames;

			int wave_delay_frames=lrint(floor(wave_delay));
			float wave_delay_frac=wave_delay-(float)wave_delay_frames;

			/** COMPUTE RINGBUFFER POS**/

			unsigned int rb_source=local_rb_pos;
			rb_source-=delay_frames;

			rb_source-=wave_delay_frames;

			/** READ FROM RINGBUFFER, LINEARLY INTERPOLATE */

			AudioFrame val=rb_buff[rb_source&buffer_mask];
			AudioFrame val_next=rb_buff[(rb_source-1)&buffer_mask];

			val+=(val_next-val)*wave_delay_frac;

			val=val*c1+h*c2;
			h=val;

			/** MIX VALUE TO OUTPUT **/

			dst_buff[i]+=val*vol_modifier;

			local_cycles+=increment;
			local_rb_pos++;

		}

		filter_h[vc]=h;
		cycles[vc]+=Math::fast_ftoi(cycles_to_mix*(double)(1<<AudioEffectChorus::CYCLES_FRAC));
	}

	buffer_pos+=p_frame_count;
}


Ref<AudioEffectInstance> AudioEffectChorus::instance() {

	Ref<AudioEffectChorusInstance> ins;
	ins.instance();
	ins->base=Ref<AudioEffectChorus>(this);
	for(int i=0;i<4;i++) {
		ins->filter_h[i]=AudioFrame(0,0);
		ins->cycles[i]=0;
	}

	float ring_buffer_max_size=AudioEffectChorus::MAX_DELAY_MS+AudioEffectChorus::MAX_DEPTH_MS+AudioEffectChorus::MAX_WIDTH_MS;

	ring_buffer_max_size*=2; //just to avoid complications
	ring_buffer_max_size/=1000.0;//convert to seconds
	ring_buffer_max_size*=AudioServer::get_singleton()->get_mix_rate();

	int ringbuff_size=ring_buffer_max_size;

	int bits=0;

	while(ringbuff_size>0) {
		bits++;
		ringbuff_size/=2;
	}

	ringbuff_size=1<<bits;
	ins->buffer_mask=ringbuff_size-1;
	ins->buffer_pos=0;
	ins->audio_buffer.resize(ringbuff_size);
	for(int i=0;i<ringbuff_size;i++) {
		ins->audio_buffer[i]=AudioFrame(0,0);
	}

	return ins;
}

void AudioEffectChorus::set_voice_count(int p_voices) {

	ERR_FAIL_COND(p_voices<1 || p_voices>=MAX_VOICES);
	voice_count=p_voices;
	_change_notify();
}


int AudioEffectChorus::get_voice_count() const{

	return voice_count;
}

void AudioEffectChorus::set_voice_delay_ms(int p_voice,float p_delay_ms){

	ERR_FAIL_INDEX(p_voice,MAX_VOICES);

	voice[p_voice].delay=p_delay_ms;

}
float AudioEffectChorus::get_voice_delay_ms(int p_voice) const{

	ERR_FAIL_INDEX_V(p_voice,MAX_VOICES,0);
	return voice[p_voice].delay;
}

void AudioEffectChorus::set_voice_rate_hz(int p_voice,float p_rate_hz){
	ERR_FAIL_INDEX(p_voice,MAX_VOICES);

	voice[p_voice].rate=p_rate_hz;
}
float AudioEffectChorus::get_voice_rate_hz(int p_voice) const{

	ERR_FAIL_INDEX_V(p_voice,MAX_VOICES,0);

	return voice[p_voice].rate;
}

void AudioEffectChorus::set_voice_depth_ms(int p_voice,float p_depth_ms){

	ERR_FAIL_INDEX(p_voice,MAX_VOICES);

	voice[p_voice].depth=p_depth_ms;
}
float AudioEffectChorus::get_voice_depth_ms(int p_voice) const{

	ERR_FAIL_INDEX_V(p_voice,MAX_VOICES,0);

	return voice[p_voice].depth;
}

void AudioEffectChorus::set_voice_level_db(int p_voice,float p_level_db){

	ERR_FAIL_INDEX(p_voice,MAX_VOICES);

	voice[p_voice].level=p_level_db;
}
float AudioEffectChorus::get_voice_level_db(int p_voice) const{

	ERR_FAIL_INDEX_V(p_voice,MAX_VOICES,0);

	return voice[p_voice].level;
}


void AudioEffectChorus::set_voice_cutoff_hz(int p_voice,float p_cutoff_hz){

	ERR_FAIL_INDEX(p_voice,MAX_VOICES);

	voice[p_voice].cutoff=p_cutoff_hz;
}
float AudioEffectChorus::get_voice_cutoff_hz(int p_voice) const{

	ERR_FAIL_INDEX_V(p_voice,MAX_VOICES,0);

	return voice[p_voice].cutoff;
}

void AudioEffectChorus::set_voice_pan(int p_voice,float p_pan){

	ERR_FAIL_INDEX(p_voice,MAX_VOICES);

	voice[p_voice].pan=p_pan;
}
float AudioEffectChorus::get_voice_pan(int p_voice) const{

	ERR_FAIL_INDEX_V(p_voice,MAX_VOICES,0);

	return voice[p_voice].pan;
}


void AudioEffectChorus::set_wet(float amount){


	wet=amount;
}
float AudioEffectChorus::get_wet() const{

	return wet;
}

void AudioEffectChorus::set_dry(float amount){

	dry=amount;

}
float AudioEffectChorus::get_dry() const{

	return dry;
}

void AudioEffectChorus::_validate_property(PropertyInfo& property) const {

	if (property.name.begins_with("voice/")) {
		int voice_idx = property.name.get_slice("/",1).to_int();
		if (voice_idx>voice_count) {
			property.usage=0;
		}
	}
}


void AudioEffectChorus::_bind_methods() {

	ClassDB::bind_method(D_METHOD("set_voice_count","voices"),&AudioEffectChorus::set_voice_count);
	ClassDB::bind_method(D_METHOD("get_voice_count"),&AudioEffectChorus::get_voice_count);


	ClassDB::bind_method(D_METHOD("set_voice_delay_ms","voice_idx","delay_ms"),&AudioEffectChorus::set_voice_delay_ms);
	ClassDB::bind_method(D_METHOD("get_voice_delay_ms","voice_idx"),&AudioEffectChorus::get_voice_delay_ms);

	ClassDB::bind_method(D_METHOD("set_voice_rate_hz","voice_idx","rate_hz"),&AudioEffectChorus::set_voice_rate_hz);
	ClassDB::bind_method(D_METHOD("get_voice_rate_hz","voice_idx"),&AudioEffectChorus::get_voice_rate_hz);

	ClassDB::bind_method(D_METHOD("set_voice_depth_ms","voice_idx","depth_ms"),&AudioEffectChorus::set_voice_depth_ms);
	ClassDB::bind_method(D_METHOD("get_voice_depth_ms","voice_idx"),&AudioEffectChorus::get_voice_depth_ms);

	ClassDB::bind_method(D_METHOD("set_voice_level_db","voice_idx","level_db"),&AudioEffectChorus::set_voice_level_db);
	ClassDB::bind_method(D_METHOD("get_voice_level_db","voice_idx"),&AudioEffectChorus::get_voice_level_db);

	ClassDB::bind_method(D_METHOD("set_voice_cutoff_hz","voice_idx","cutoff_hz"),&AudioEffectChorus::set_voice_cutoff_hz);
	ClassDB::bind_method(D_METHOD("get_voice_cutoff_hz","voice_idx"),&AudioEffectChorus::get_voice_cutoff_hz);

	ClassDB::bind_method(D_METHOD("set_voice_pan","voice_idx","pan"),&AudioEffectChorus::set_voice_pan);
	ClassDB::bind_method(D_METHOD("get_voice_pan","voice_idx"),&AudioEffectChorus::get_voice_pan);

	ClassDB::bind_method(D_METHOD("set_wet","amount"),&AudioEffectChorus::set_wet);
	ClassDB::bind_method(D_METHOD("get_wet"),&AudioEffectChorus::get_wet);

	ClassDB::bind_method(D_METHOD("set_dry","amount"),&AudioEffectChorus::set_dry);
	ClassDB::bind_method(D_METHOD("get_dry"),&AudioEffectChorus::get_dry);

	ADD_PROPERTY(PropertyInfo(Variant::INT,"voice_count",PROPERTY_HINT_RANGE,"1,4,1"),"set_voice_count","get_voice_count");
	ADD_PROPERTY(PropertyInfo(Variant::REAL,"dry",PROPERTY_HINT_RANGE,"0,1,0.01"),"set_dry","get_dry");
	ADD_PROPERTY(PropertyInfo(Variant::REAL,"wet",PROPERTY_HINT_RANGE,"0,1,0.01"),"set_wet","get_wet");

	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/1/delay_ms",PROPERTY_HINT_RANGE,"0,50,0.01"),"set_voice_delay_ms","get_voice_delay_ms",0);
	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/1/rate_hz",PROPERTY_HINT_RANGE,"0.1,20,0.1"),"set_voice_rate_hz","get_voice_rate_hz",0);
	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/1/depth_ms",PROPERTY_HINT_RANGE,"0,20,0.01"),"set_voice_depth_ms","get_voice_depth_ms",0);
	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/1/level_db",PROPERTY_HINT_RANGE,"-60,24,0.1"),"set_voice_level_db","get_voice_level_db",0);
	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/1/cutoff_hz",PROPERTY_HINT_RANGE,"1,16000,1"),"set_voice_cutoff_hz","get_voice_cutoff_hz",0);
	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/1/pan",PROPERTY_HINT_RANGE,"-1,1,0.01"),"set_voice_pan","get_voice_pan",0);

	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/2/delay_ms",PROPERTY_HINT_RANGE,"0,50,0.01"),"set_voice_delay_ms","get_voice_delay_ms",1);
	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/2/rate_hz",PROPERTY_HINT_RANGE,"0.1,20,0.1"),"set_voice_rate_hz","get_voice_rate_hz",1);
	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/2/depth_ms",PROPERTY_HINT_RANGE,"0,20,0.01"),"set_voice_depth_ms","get_voice_depth_ms",1);
	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/2/level_db",PROPERTY_HINT_RANGE,"-60,24,0.1"),"set_voice_level_db","get_voice_level_db",1);
	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/2/cutoff_hz",PROPERTY_HINT_RANGE,"1,16000,1"),"set_voice_cutoff_hz","get_voice_cutoff_hz",1);
	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/2/pan",PROPERTY_HINT_RANGE,"-1,1,0.01"),"set_voice_pan","get_voice_pan",1);

	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/3/delay_ms",PROPERTY_HINT_RANGE,"0,50,0.01"),"set_voice_delay_ms","get_voice_delay_ms",2);
	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/3/rate_hz",PROPERTY_HINT_RANGE,"0.1,20,0.1"),"set_voice_rate_hz","get_voice_rate_hz",2);
	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/3/depth_ms",PROPERTY_HINT_RANGE,"0,20,0.01"),"set_voice_depth_ms","get_voice_depth_ms",2);
	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/3/level_db",PROPERTY_HINT_RANGE,"-60,24,0.1"),"set_voice_level_db","get_voice_level_db",2);
	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/3/cutoff_hz",PROPERTY_HINT_RANGE,"1,16000,1"),"set_voice_cutoff_hz","get_voice_cutoff_hz",2);
	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/3/pan",PROPERTY_HINT_RANGE,"-1,1,0.01"),"set_voice_pan","get_voice_pan",2);

	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/4/delay_ms",PROPERTY_HINT_RANGE,"0,50,0.01"),"set_voice_delay_ms","get_voice_delay_ms",3);
	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/4/rate_hz",PROPERTY_HINT_RANGE,"0.1,20,0.1"),"set_voice_rate_hz","get_voice_rate_hz",3);
	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/4/depth_ms",PROPERTY_HINT_RANGE,"0,20,0.01"),"set_voice_depth_ms","get_voice_depth_ms",3);
	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/4/level_db",PROPERTY_HINT_RANGE,"-60,24,0.1"),"set_voice_level_db","get_voice_level_db",3);
	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/4/cutoff_hz",PROPERTY_HINT_RANGE,"1,16000,1"),"set_voice_cutoff_hz","get_voice_cutoff_hz",3);
	ADD_PROPERTYI(PropertyInfo(Variant::REAL,"voice/4/pan",PROPERTY_HINT_RANGE,"-1,1,0.01"),"set_voice_pan","get_voice_pan",3);

}

AudioEffectChorus::AudioEffectChorus()
{
	voice_count=2;
	voice[0].delay=15;
	voice[1].delay=20;
	voice[0].rate=0.8;
	voice[1].rate=1.2;
	voice[0].depth=2;
	voice[1].depth=3;
	voice[0].cutoff=8000;
	voice[1].cutoff=8000;
	voice[0].pan=-0.5;
	voice[1].pan=0.5;

	wet=0.5;
	dry=1.0;
}