godot/servers/audio/effects/audio_effect_amplify.cpp

#include "audio_effect_amplify.h"


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


	//multiply volume interpolating to avoid clicks if this changes
	float volume_db = base->volume_db;
	float vol = Math::db2linear(mix_volume_db);
	float vol_inc = (Math::db2linear(volume_db) - vol)/float(p_frame_count);

	for(int i=0;i<p_frame_count;i++) {
		p_dst_frames[i]=p_src_frames[i]*vol;
		vol+=vol_inc;
	}
	//set volume for next mix
	mix_volume_db = volume_db;

}


Ref<AudioEffectInstance> AudioEffectAmplify::instance() {
	Ref<AudioEffectAmplifyInstance> ins;
	ins.instance();
	ins->base=Ref<AudioEffectAmplify>(this);
	ins->mix_volume_db=volume_db;
	return ins;
}

void AudioEffectAmplify::set_volume_db(float p_volume) {
	volume_db=p_volume;
}

float AudioEffectAmplify::get_volume_db() const {

	return volume_db;
}

void AudioEffectAmplify::_bind_methods() {

	ClassDB::bind_method(D_METHOD("set_volume_db","volume"),&AudioEffectAmplify::set_volume_db);
	ClassDB::bind_method(D_METHOD("get_volume_db"),&AudioEffectAmplify::get_volume_db);

	ADD_PROPERTY(PropertyInfo(Variant::REAL,"volume_db",PROPERTY_HINT_RANGE,"-80,24,0.01"),"set_volume_db","get_volume_db");
}

AudioEffectAmplify::AudioEffectAmplify()
{
	volume_db=0;
}