distortion effect

servers/audio/effects/audio_effect_distortion.cpp

@@ -0,0 +1,170 @@
+#include "audio_effect_distortion.h"
+#include "servers/audio_server.h"
+
+
+
+void AudioEffectDistortionInstance::process(const AudioFrame *p_src_frames,AudioFrame *p_dst_frames,int p_frame_count) {
+
+	const float *src = (const float*)p_src_frames;
+	float *dst = (float*)p_dst_frames;
+
+	//float lpf_c=expf(-2.0*M_PI*keep_hf_hz.get()/(mix_rate*(float)OVERSAMPLE));
+	float lpf_c=expf(-2.0*M_PI*base->keep_hf_hz/(AudioServer::get_singleton()->get_mix_rate()));
+	float lpf_ic=1.0-lpf_c;
+
+	float drive_f=base->drive;
+	float pregain_f=Math::db2linear(base->pre_gain);
+	float postgain_f=Math::db2linear(base->post_gain);
+
+	float atan_mult=pow(10,drive_f*drive_f*3.0)-1.0+0.001;
+	float atan_div=1.0/(atanf(atan_mult)*(1.0+drive_f*8));
+
+	float lofi_mult=powf(2.0,2.0+(1.0-drive_f)*14); //goes from 16 to 2 bits
+
+	for (int i=0;i<p_frame_count*2;i++) {
+
+		float out=undenormalise(src[i]*lpf_ic+lpf_c*h[i&1]);
+		h[i&1]=out;
+		float a=out;
+		float ha=src[i]-out; //high freqs
+		a*=pregain_f;
+
+		switch (base->mode) {
+
+			case AudioEffectDistortion::MODE_CLIP: {
+
+				a=powf(a,1.0001-drive_f);
+				if (a>1.0)
+					a=1.0;
+				else if (a<(-1.0))
+					a=-1.0;
+
+			} break;
+			case AudioEffectDistortion::MODE_ATAN: {
+
+
+				a=atanf(a*atan_mult)*atan_div;
+
+			} break;
+			case AudioEffectDistortion::MODE_LOFI: {
+
+				a = floorf(a*lofi_mult+0.5)/lofi_mult;
+
+			} break;
+			case AudioEffectDistortion::MODE_OVERDRIVE: {
+
+
+				const double x = a * 0.686306;
+				const double z = 1 + exp (sqrt (fabs (x)) * -0.75);
+				a = (expf(x) - expf(-x * z)) / (expf(x) + expf(-x));
+			} break;
+			case AudioEffectDistortion::MODE_WAVESHAPE: {
+				float x = a;
+				float k= 2*drive_f/(1.00001-drive_f);
+
+				a = (1.0+k)*x/(1.0+k*fabsf(x));
+
+
+			} break;
+		}
+
+		dst[i]=a*postgain_f+ha;
+
+	}
+
+
+}
+
+
+Ref<AudioEffectInstance> AudioEffectDistortion::instance() {
+	Ref<AudioEffectDistortionInstance> ins;
+	ins.instance();
+	ins->base=Ref<AudioEffectDistortion>(this);
+	ins->h[0]=0;
+	ins->h[1]=0;
+
+	return ins;
+}
+
+
+void AudioEffectDistortion::set_mode(Mode p_mode) {
+
+	mode=p_mode;
+}
+
+AudioEffectDistortion::Mode AudioEffectDistortion::get_mode() const{
+
+	return mode;
+}
+
+void AudioEffectDistortion::set_pre_gain(float p_pre_gain){
+
+	pre_gain=p_pre_gain;
+}
+float AudioEffectDistortion::get_pre_gain() const{
+
+	return pre_gain;
+}
+
+void AudioEffectDistortion::set_keep_hf_hz(float p_keep_hf_hz){
+
+	keep_hf_hz=p_keep_hf_hz;
+}
+float AudioEffectDistortion::get_keep_hf_hz() const{
+
+	return keep_hf_hz;
+}
+
+void AudioEffectDistortion::set_drive(float p_drive){
+
+	drive=p_drive;
+}
+float AudioEffectDistortion::get_drive() const{
+
+	return drive;
+}
+
+void AudioEffectDistortion::set_post_gain(float p_post_gain){
+
+	post_gain=p_post_gain;
+}
+float AudioEffectDistortion::get_post_gain() const{
+
+	return post_gain;
+}
+
+
+void AudioEffectDistortion::_bind_methods() {
+
+	ClassDB::bind_method(_MD("set_mode","mode"),&AudioEffectDistortion::set_mode);
+	ClassDB::bind_method(_MD("get_mode"),&AudioEffectDistortion::get_mode);
+
+	ClassDB::bind_method(_MD("set_pre_gain","pre_gain"),&AudioEffectDistortion::set_pre_gain);
+	ClassDB::bind_method(_MD("get_pre_gain"),&AudioEffectDistortion::get_pre_gain);
+
+	ClassDB::bind_method(_MD("set_keep_hf_hz","keep_hf_hz"),&AudioEffectDistortion::set_keep_hf_hz);
+	ClassDB::bind_method(_MD("get_keep_hf_hz"),&AudioEffectDistortion::get_keep_hf_hz);
+
+	ClassDB::bind_method(_MD("set_drive","drive"),&AudioEffectDistortion::set_drive);
+	ClassDB::bind_method(_MD("get_drive"),&AudioEffectDistortion::get_drive);
+
+
+	ClassDB::bind_method(_MD("set_post_gain","post_gain"),&AudioEffectDistortion::set_post_gain);
+	ClassDB::bind_method(_MD("get_post_gain"),&AudioEffectDistortion::get_post_gain);
+
+	ADD_PROPERTY(PropertyInfo(Variant::INT,"mode",PROPERTY_HINT_ENUM,"Clip,ATan,LoFi,Overdrive,WaveShape"),_SCS("set_mode"),_SCS("get_mode"));
+	ADD_PROPERTY(PropertyInfo(Variant::REAL,"pre_gain",PROPERTY_HINT_RANGE,"-60,60,0.01"),_SCS("set_pre_gain"),_SCS("get_pre_gain"));
+	ADD_PROPERTY(PropertyInfo(Variant::REAL,"keep_hf_hz",PROPERTY_HINT_RANGE,"1,20000,1"),_SCS("set_keep_hf_hz"),_SCS("get_keep_hf_hz"));
+	ADD_PROPERTY(PropertyInfo(Variant::REAL,"drive",PROPERTY_HINT_RANGE,"0,1,0.01"),_SCS("set_drive"),_SCS("get_drive"));
+	ADD_PROPERTY(PropertyInfo(Variant::REAL,"post_gain",PROPERTY_HINT_RANGE,"-80,24,0.01"),_SCS("set_post_gain"),_SCS("get_post_gain"));
+}
+
+AudioEffectDistortion::AudioEffectDistortion()
+{
+	mode=MODE_CLIP;
+	pre_gain=0;
+	post_gain=0;
+	keep_hf_hz=16000;
+	drive=0;
+}
+

servers/audio/effects/audio_effect_distortion.h

@@ -0,0 +1,69 @@
+#ifndef AUDIOEFFECTDISTORTION_H
+#define AUDIOEFFECTDISTORTION_H
+
+#include "servers/audio/audio_effect.h"
+
+class AudioEffectDistortion;
+
+class AudioEffectDistortionInstance : public AudioEffectInstance {
+	GDCLASS(AudioEffectDistortionInstance,AudioEffectInstance)
+friend class AudioEffectDistortion;
+	Ref<AudioEffectDistortion> base;
+	float h[2];
+public:
+
+	virtual void process(const AudioFrame *p_src_frames,AudioFrame *p_dst_frames,int p_frame_count);
+
+};
+
+
+class AudioEffectDistortion : public AudioEffect {
+	GDCLASS(AudioEffectDistortion,AudioEffect)
+public:
+	enum Mode {
+		MODE_CLIP,
+		MODE_ATAN,
+		MODE_LOFI,
+		MODE_OVERDRIVE,
+		MODE_WAVESHAPE,
+	};
+
+friend class AudioEffectDistortionInstance;
+	Mode mode;
+	float pre_gain;
+	float post_gain;
+	float keep_hf_hz;
+	float drive;
+
+protected:
+
+	static void _bind_methods();
+public:
+
+
+	Ref<AudioEffectInstance> instance();
+
+
+	void set_mode(Mode p_mode);
+	Mode get_mode() const;
+
+	void set_pre_gain(float pre_gain);
+	float get_pre_gain() const;
+
+	void set_keep_hf_hz(float keep_hf_hz);
+	float get_keep_hf_hz() const;
+
+	void set_drive(float drive);
+	float get_drive() const;
+
+	void set_post_gain(float post_gain);
+	float get_post_gain() const;
+
+
+
+	AudioEffectDistortion();
+};
+
+VARIANT_ENUM_CAST( AudioEffectDistortion::Mode )
+
+#endif // AUDIOEFFECTDISTORTION_H

servers/register_server_types.cpp

@@ -41,6 +41,7 @@
 #include "audio/effects/audio_effect_reverb.h"
 #include "audio/effects/audio_effect_filter.h"
 #include "audio/effects/audio_effect_eq.h"
+#include "audio/effects/audio_effect_distortion.h"
 
 static void _debugger_get_resource_usage(List<ScriptDebuggerRemote::ResourceUsage>* r_usage) {
 
@@ -93,6 +94,7 @@ void register_server_types() {
 	ClassDB::register_class<AudioEffectEQ10>();
 	ClassDB::register_class<AudioEffectEQ21>();
 
+	ClassDB::register_class<AudioEffectDistortion>();
 
 	ClassDB::register_virtual_class<Physics2DDirectBodyState>();
 	ClassDB::register_virtual_class<Physics2DDirectSpaceState>();