/*************************************************************************/
/*  audio_effect_pitch_shift.h                                           */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
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/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
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#ifndef AUDIO_EFFECT_PITCH_SHIFT_H
#define AUDIO_EFFECT_PITCH_SHIFT_H

#include "servers/audio/audio_effect.h"

class SMBPitchShift {
	enum {
		MAX_FRAME_LENGTH = 8192
	};

	float gInFIFO[MAX_FRAME_LENGTH];
	float gOutFIFO[MAX_FRAME_LENGTH];
	double gFFTworksp[2 * MAX_FRAME_LENGTH];
	double gLastPhase[MAX_FRAME_LENGTH / 2 + 1];
	double gSumPhase[MAX_FRAME_LENGTH / 2 + 1];
	double gOutputAccum[2 * MAX_FRAME_LENGTH];
	double gAnaFreq[MAX_FRAME_LENGTH];
	double gAnaMagn[MAX_FRAME_LENGTH];
	double gSynFreq[MAX_FRAME_LENGTH];
	double gSynMagn[MAX_FRAME_LENGTH];
	int64_t gRover;
	float lastPitchShift;

	void smbFft(double *fftBuffer, int64_t fftFrameSize, int64_t sign);

public:
	void PitchShift(float pitchShift, int64_t numSampsToProcess, int64_t fftFrameSize, int64_t osamp, float sampleRate, float *indata, float *outdata, int stride);

	SMBPitchShift() {
		gRover = 0;
		memset(gInFIFO, 0, MAX_FRAME_LENGTH * sizeof(float));
		memset(gOutFIFO, 0, MAX_FRAME_LENGTH * sizeof(float));
		memset(gFFTworksp, 0, 2 * MAX_FRAME_LENGTH * sizeof(double));
		memset(gLastPhase, 0, (MAX_FRAME_LENGTH / 2 + 1) * sizeof(double));
		memset(gSumPhase, 0, (MAX_FRAME_LENGTH / 2 + 1) * sizeof(double));
		memset(gOutputAccum, 0, 2 * MAX_FRAME_LENGTH * sizeof(double));
		memset(gAnaFreq, 0, MAX_FRAME_LENGTH * sizeof(double));
		memset(gAnaMagn, 0, MAX_FRAME_LENGTH * sizeof(double));
		lastPitchShift = 1.0;
	}
};

class AudioEffectPitchShift;

class AudioEffectPitchShiftInstance : public AudioEffectInstance {
	GDCLASS(AudioEffectPitchShiftInstance, AudioEffectInstance);
	friend class AudioEffectPitchShift;
	Ref<AudioEffectPitchShift> base;

	int fft_size;
	SMBPitchShift shift_l;
	SMBPitchShift shift_r;

public:
	virtual void process(const AudioFrame *p_src_frames, AudioFrame *p_dst_frames, int p_frame_count) override;
};

class AudioEffectPitchShift : public AudioEffect {
	GDCLASS(AudioEffectPitchShift, AudioEffect);

public:
	friend class AudioEffectPitchShiftInstance;

	enum FFTSize {
		FFT_SIZE_256,
		FFT_SIZE_512,
		FFT_SIZE_1024,
		FFT_SIZE_2048,
		FFT_SIZE_4096,
		FFT_SIZE_MAX
	};

	float pitch_scale;
	int oversampling;
	FFTSize fft_size;

protected:
	static void _bind_methods();

public:
	Ref<AudioEffectInstance> instantiate() override;

	void set_pitch_scale(float p_pitch_scale);
	float get_pitch_scale() const;

	void set_oversampling(int p_oversampling);
	int get_oversampling() const;

	void set_fft_size(FFTSize);
	FFTSize get_fft_size() const;

	AudioEffectPitchShift();
};

VARIANT_ENUM_CAST(AudioEffectPitchShift::FFTSize);

#endif // AUDIO_EFFECT_PITCH_SHIFT_H