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

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

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



	float main_level_f=base->dry;


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

	float tap_1_level_f=base->tap_1_active?Math::db2linear(base->tap_1_level):0.0;
	int tap_1_delay_frames=int((base->tap_1_delay_ms/1000.0)*mix_rate);;

	float tap_2_level_f=base->tap_2_active?Math::db2linear(base->tap_2_level):0.0;
	int tap_2_delay_frames=int((base->tap_2_delay_ms/1000.0)*mix_rate);;

	float feedback_level_f=base->feedback_active?Math::db2linear(base->feedback_level):0.0;
	unsigned int feedback_delay_frames=int((base->feedback_delay_ms/1000.0)*mix_rate);;


	AudioFrame tap1_vol=AudioFrame(tap_1_level_f,tap_1_level_f);

	tap1_vol.l*=CLAMP( 1.0 - base->tap_1_pan, 0, 1);
	tap1_vol.r*=CLAMP( 1.0 + base->tap_1_pan, 0, 1);

	AudioFrame tap2_vol=AudioFrame(tap_2_level_f,tap_2_level_f);

	tap2_vol.l*=CLAMP( 1.0 - base->tap_2_pan, 0, 1);
	tap2_vol.r*=CLAMP( 1.0 + base->tap_2_pan, 0, 1);

	// feedback lowpass here
	float lpf_c=expf(-2.0*Math_PI*base->feedback_lowpass/mix_rate); // 0 .. 10khz
	float lpf_ic=1.0-lpf_c;

	const AudioFrame *src=p_src_frames;
	AudioFrame *dst=p_dst_frames;
	AudioFrame *rb_buf=ring_buffer.ptr();
	AudioFrame *fb_buf=feedback_buffer.ptr();


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


		rb_buf[ring_buffer_pos&ring_buffer_mask]=src[i];

		AudioFrame main_val=src[i]*main_level_f;
		AudioFrame tap_1_val=rb_buf[(ring_buffer_pos-tap_1_delay_frames)&ring_buffer_mask]*tap1_vol;
		AudioFrame tap_2_val=rb_buf[(ring_buffer_pos-tap_2_delay_frames)&ring_buffer_mask]*tap2_vol;

		AudioFrame out=main_val+tap_1_val+tap_2_val;

		out+=fb_buf[ feedback_buffer_pos ];

		//apply lowpass and feedback gain
		AudioFrame fb_in=out*feedback_level_f*lpf_ic+h*lpf_c;
		fb_in.undenormalise(); //avoid denormals

		h=fb_in;
		fb_buf[ feedback_buffer_pos ]=fb_in;

		dst[i]=out;

		ring_buffer_pos++;

		if ( (++feedback_buffer_pos) >= feedback_delay_frames )
			feedback_buffer_pos=0;
	}
}



Ref<AudioEffectInstance> AudioEffectDelay::instance() {
	Ref<AudioEffectDelayInstance> ins;
	ins.instance();
	ins->base=Ref<AudioEffectDelay>(this);

	float ring_buffer_max_size=MAX_DELAY_MS+100; //add 100ms of extra room, just in case
	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->ring_buffer_mask=ringbuff_size-1;
	ins->ring_buffer_pos=0;

	ins->ring_buffer.resize( ringbuff_size );
	ins->feedback_buffer.resize( ringbuff_size );

	ins->feedback_buffer_pos=0;

	ins->h=AudioFrame(0,0);

	return ins;
}


void AudioEffectDelay::set_dry(float p_dry) {

	dry=p_dry;
}

float AudioEffectDelay::get_dry(){

	return dry;
}

void AudioEffectDelay::set_tap1_active(bool p_active){

	tap_1_active=p_active;
}
bool AudioEffectDelay::is_tap1_active() const{

	return tap_1_active;
}

void AudioEffectDelay::set_tap1_delay_ms(float p_delay_ms){

	tap_1_delay_ms=p_delay_ms;
}
float AudioEffectDelay::get_tap1_delay_ms() const{

	return tap_1_delay_ms;
}

void AudioEffectDelay::set_tap1_level_db(float p_level_db){

	tap_1_level=p_level_db;
}
float AudioEffectDelay::get_tap1_level_db() const{

	return tap_1_level;
}

void AudioEffectDelay::set_tap1_pan(float p_pan){

	tap_1_pan=p_pan;
}
float AudioEffectDelay::get_tap1_pan() const{

	return tap_1_pan;
}


void AudioEffectDelay::set_tap2_active(bool p_active){

	tap_2_active=p_active;
}
bool AudioEffectDelay::is_tap2_active() const{

	return tap_2_active;
}

void AudioEffectDelay::set_tap2_delay_ms(float p_delay_ms){

	tap_2_delay_ms=p_delay_ms;
}
float AudioEffectDelay::get_tap2_delay_ms() const{

	return tap_2_delay_ms;
}

void AudioEffectDelay::set_tap2_level_db(float p_level_db){

	tap_2_level=p_level_db;
}
float AudioEffectDelay::get_tap2_level_db() const{

	return tap_2_level;
}

void AudioEffectDelay::set_tap2_pan(float p_pan){

	tap_2_pan=p_pan;
}
float AudioEffectDelay::get_tap2_pan() const{

	return tap_2_pan;
}

void AudioEffectDelay::set_feedback_active(bool p_active){

	feedback_active=p_active;
}
bool AudioEffectDelay::is_feedback_active() const{

	return feedback_active;
}

void AudioEffectDelay::set_feedback_delay_ms(float p_delay_ms){

	feedback_delay_ms=p_delay_ms;
}
float AudioEffectDelay::get_feedback_delay_ms() const{

	return feedback_delay_ms;
}

void AudioEffectDelay::set_feedback_level_db(float p_level_db){

	feedback_level=p_level_db;
}
float AudioEffectDelay::get_feedback_level_db() const{

	return feedback_level;
}

void AudioEffectDelay::set_feedback_lowpass(float p_lowpass){

	feedback_lowpass=p_lowpass;
}
float AudioEffectDelay::get_feedback_lowpass() const{

	return feedback_lowpass;
}


void AudioEffectDelay::_bind_methods() {

	ClassDB::bind_method(_MD("set_dry","amount"),&AudioEffectDelay::set_dry);
	ClassDB::bind_method(_MD("get_dry"),&AudioEffectDelay::get_dry);

	ClassDB::bind_method(_MD("set_tap1_active","amount"),&AudioEffectDelay::set_tap1_active);
	ClassDB::bind_method(_MD("is_tap1_active"),&AudioEffectDelay::is_tap1_active);

	ClassDB::bind_method(_MD("set_tap1_delay_ms","amount"),&AudioEffectDelay::set_tap1_delay_ms);
	ClassDB::bind_method(_MD("get_tap1_delay_ms"),&AudioEffectDelay::get_tap1_delay_ms);

	ClassDB::bind_method(_MD("set_tap1_level_db","amount"),&AudioEffectDelay::set_tap1_level_db);
	ClassDB::bind_method(_MD("get_tap1_level_db"),&AudioEffectDelay::get_tap1_level_db);

	ClassDB::bind_method(_MD("set_tap1_pan","amount"),&AudioEffectDelay::set_tap1_pan);
	ClassDB::bind_method(_MD("get_tap1_pan"),&AudioEffectDelay::get_tap1_pan);

	ClassDB::bind_method(_MD("set_tap2_active","amount"),&AudioEffectDelay::set_tap2_active);
	ClassDB::bind_method(_MD("is_tap2_active"),&AudioEffectDelay::is_tap2_active);

	ClassDB::bind_method(_MD("set_tap2_delay_ms","amount"),&AudioEffectDelay::set_tap2_delay_ms);
	ClassDB::bind_method(_MD("get_tap2_delay_ms"),&AudioEffectDelay::get_tap2_delay_ms);

	ClassDB::bind_method(_MD("set_tap2_level_db","amount"),&AudioEffectDelay::set_tap2_level_db);
	ClassDB::bind_method(_MD("get_tap2_level_db"),&AudioEffectDelay::get_tap2_level_db);

	ClassDB::bind_method(_MD("set_tap2_pan","amount"),&AudioEffectDelay::set_tap2_pan);
	ClassDB::bind_method(_MD("get_tap2_pan"),&AudioEffectDelay::get_tap2_pan);


	ClassDB::bind_method(_MD("set_feedback_active","amount"),&AudioEffectDelay::set_feedback_active);
	ClassDB::bind_method(_MD("is_feedback_active"),&AudioEffectDelay::is_feedback_active);

	ClassDB::bind_method(_MD("set_feedback_delay_ms","amount"),&AudioEffectDelay::set_feedback_delay_ms);
	ClassDB::bind_method(_MD("get_feedback_delay_ms"),&AudioEffectDelay::get_feedback_delay_ms);

	ClassDB::bind_method(_MD("set_feedback_level_db","amount"),&AudioEffectDelay::set_feedback_level_db);
	ClassDB::bind_method(_MD("get_feedback_level_db"),&AudioEffectDelay::get_feedback_level_db);

	ClassDB::bind_method(_MD("set_feedback_lowpass","amount"),&AudioEffectDelay::set_feedback_lowpass);
	ClassDB::bind_method(_MD("get_feedback_lowpass"),&AudioEffectDelay::get_feedback_lowpass);

	ADD_PROPERTY(PropertyInfo(Variant::REAL,"dry",PROPERTY_HINT_RANGE,"0,1,0.01"),"set_dry","get_dry");

	ADD_PROPERTY(PropertyInfo(Variant::BOOL,"tap1/active"),"set_tap1_active","is_tap1_active");
	ADD_PROPERTY(PropertyInfo(Variant::REAL,"tap1/delay_ms",PROPERTY_HINT_RANGE,"0,1500,1"),"set_tap1_delay_ms","get_tap1_delay_ms");
	ADD_PROPERTY(PropertyInfo(Variant::REAL,"tap1/level_db",PROPERTY_HINT_RANGE,"-60,0,0.01"),"set_tap1_level_db","get_tap1_level_db");
	ADD_PROPERTY(PropertyInfo(Variant::REAL,"tap1/pan",PROPERTY_HINT_RANGE,"-1,1,0.01"),"set_tap1_pan","get_tap1_pan");

	ADD_PROPERTY(PropertyInfo(Variant::BOOL,"tap2/active"),"set_tap2_active","is_tap2_active");
	ADD_PROPERTY(PropertyInfo(Variant::REAL,"tap2/delay_ms",PROPERTY_HINT_RANGE,"0,1500,1"),"set_tap2_delay_ms","get_tap2_delay_ms");
	ADD_PROPERTY(PropertyInfo(Variant::REAL,"tap2/level_db",PROPERTY_HINT_RANGE,"-60,0,0.01"),"set_tap2_level_db","get_tap2_level_db");
	ADD_PROPERTY(PropertyInfo(Variant::REAL,"tap2/pan",PROPERTY_HINT_RANGE,"-1,1,0.01"),"set_tap2_pan","get_tap2_pan");

	ADD_PROPERTY(PropertyInfo(Variant::BOOL,"feedback/active"),"set_feedback_active","is_feedback_active");
	ADD_PROPERTY(PropertyInfo(Variant::REAL,"feedback/delay_ms",PROPERTY_HINT_RANGE,"0,1500,1"),"set_feedback_delay_ms","get_feedback_delay_ms");
	ADD_PROPERTY(PropertyInfo(Variant::REAL,"feedback/level_db",PROPERTY_HINT_RANGE,"-60,0,0.01"),"set_feedback_level_db","get_feedback_level_db");
	ADD_PROPERTY(PropertyInfo(Variant::REAL,"feedback/lowpass",PROPERTY_HINT_RANGE,"1,16000,1"),"set_feedback_lowpass","get_feedback_lowpass");


}

AudioEffectDelay::AudioEffectDelay()
{
	tap_1_active=true;
	tap_1_delay_ms=250;
	tap_1_level=-6;
	tap_1_pan=0.2;

	tap_2_active=true;
	tap_2_delay_ms=500;
	tap_2_level=-12;
	tap_2_pan=-0.4;

	feedback_active=false;
	feedback_delay_ms=340;
	feedback_level=-6;
	feedback_lowpass=16000;

	dry=1.0;

}