text: /*************************************************************************/
  /*  audio_effect_phaser.h                                                */
  /*************************************************************************/
  /*                       This file is part of:                           */
  /*                           GODOT ENGINE                                */
  /*                      https://godotengine.org                          */
  /*************************************************************************/
  /* Copyright (c) 2007-2019 Juan Linietsky, Ariel Manzur.                 */
  /* Copyright (c) 2014-2019 Godot Engine contributors (cf. AUTHORS.md)    */
  /*                                                                       */
  /* Permission is hereby granted, free of charge, to any person obtaining */
  /* a copy of this software and associated documentation files (the       */
  /* "Software"), to deal in the Software without restriction, including   */
  /* without limitation the rights to use, copy, modify, merge, publish,   */
  /* distribute, sublicense, and/or sell copies of the Software, and to    */
  /* permit persons to whom the Software is furnished to do so, subject to */
  /* the following conditions:                                             */
  /*                                                                       */
  /* The above copyright notice and this permission notice shall be        */
  /* included in all copies or substantial portions of the Software.       */
  /*                                                                       */
  /* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
  /* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
  /* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
  /* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
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  /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
  /*************************************************************************/
  
  #ifndef AUDIO_EFFECT_PHASER_H
  #define AUDIO_EFFECT_PHASER_H
  
  #include "servers/audio/audio_effect.h"
  
  class AudioEffectPhaser;
  
  class AudioEffectPhaserInstance : public AudioEffectInstance {
  	GDCLASS(AudioEffectPhaserInstance, AudioEffectInstance);
  	friend class AudioEffectPhaser;
  	Ref<AudioEffectPhaser> base;
  
  	float phase;
  	AudioFrame h;
  
  	class AllpassDelay {
  		float a, h;
  
  	public:
  		_ALWAYS_INLINE_ void delay(float d) {
  			a = (1.f - d) / (1.f + d);
  		}
  
  		_ALWAYS_INLINE_ float update(float s) {
  			float y = s * -a + h;
  			h = y * a + s;
  			return y;
  		}
  
  		AllpassDelay() {
  			a = 0;
  			h = 0;
  		}
  	};
  
  	AllpassDelay allpass[2][6];
  
  public:
  	virtual void process(const AudioFrame *p_src_frames, AudioFrame *p_dst_frames, int p_frame_count);
  };
  
  class AudioEffectPhaser : public AudioEffect {
  	GDCLASS(AudioEffectPhaser, AudioEffect);
  
  	friend class AudioEffectPhaserInstance;
  	float range_min;
  	float range_max;
  	float rate;
  	float feedback;
  	float depth;
  
  protected:
  	static void _bind_methods();
  
  public:
  	Ref<AudioEffectInstance> instance();
  
  	void set_range_min_hz(float p_hz);
  	float get_range_min_hz() const;
  
  	void set_range_max_hz(float p_hz);
  	float get_range_max_hz() const;
  
  	void set_rate_hz(float p_hz);
  	float get_rate_hz() const;
  
  	void set_feedback(float p_fbk);
  	float get_feedback() const;
  
  	void set_depth(float p_depth);
  	float get_depth() const;
  
  	AudioEffectPhaser();
  };
  
  #endif // AUDIO_EFFECT_PHASER_H
  