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MiniDexed/src/effect_mixer.hpp

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// Taken from https://github.com/manicken/Audio/tree/templateMixer
// Adapted for MiniDexed by Holger Wirtz <dcoredump@googlemail.com>
#ifndef effect_mixer_h_
#define effect_mixer_h_
#include <cstdint>
#include <assert.h>
#include "arm_math.h"
#define UNITY_GAIN 1.0f
#define MAX_GAIN 1.0f
#define MIN_GAIN 0.0f
#define UNITY_PANORAMA 1.0f
#define MAX_PANORAMA 1.0f
#define MIN_PANORAMA 0.0f
template <int NN> class AudioMixer
{
public:
AudioMixer(uint16_t len)
{
buffer_length=len;
for (uint8_t i=0; i<NN; i++)
multiplier[i] = UNITY_GAIN;
sumbufL=new float32_t[buffer_length];
arm_fill_f32(0.0f, sumbufL, len);
}
~AudioMixer()
{
delete [] sumbufL;
}
void doAddMix(uint8_t channel, float32_t* in)
{
float32_t tmp[buffer_length];
assert(in);
if(multiplier[channel]!=UNITY_GAIN)
arm_scale_f32(in,multiplier[channel],tmp,buffer_length);
arm_add_f32(sumbufL, tmp, sumbufL, buffer_length);
}
void gain(uint8_t channel, float32_t gain)
{
if (channel >= NN) return;
if (gain > MAX_GAIN)
gain = MAX_GAIN;
else if (gain < MIN_GAIN)
gain = MIN_GAIN;
multiplier[channel] = powf(gain, 4); // see: https://www.dr-lex.be/info-stuff/volumecontrols.html#ideal2
}
void gain(float32_t gain)
{
for (uint8_t i = 0; i < NN; i++)
{
if (gain > MAX_GAIN)
gain = MAX_GAIN;
else if (gain < MIN_GAIN)
gain = MIN_GAIN;
multiplier[i] = powf(gain, 4); // see: https://www.dr-lex.be/info-stuff/volumecontrols.html#ideal2
}
}
void getMix(float32_t* buffer)
{
assert(buffer);
assert(sumbufL);
arm_copy_f32(sumbufL, buffer, buffer_length);
if(sumbufL)
arm_fill_f32(0.0f, sumbufL, buffer_length);
}
protected:
float32_t multiplier[NN];
float32_t* sumbufL;
uint16_t buffer_length;
};
template <int NN> class AudioStereoMixer : public AudioMixer<NN>
{
public:
AudioStereoMixer(uint16_t len) : AudioMixer<NN>(len)
{
for (uint8_t i=0; i<NN; i++)
panorama[i] = UNITY_PANORAMA;
sumbufR=new float32_t[buffer_length];
arm_fill_f32(0.0f, sumbufR, buffer_length);
}
~AudioStereoMixer()
{
delete [] sumbufR;
}
void pan(uint8_t channel, float32_t pan)
{
if (channel >= NN) return;
if (pan > MAX_PANORAMA)
pan = MAX_PANORAMA;
else if (pan < MIN_PANORAMA)
pan = MIN_PANORAMA;
panorama[channel] = pan;
}
void doAddMix(uint8_t channel, float32_t* in)
{
float32_t tmp[buffer_length];
float32_t sin_pan;
float32_t cos_pan;
assert(in);
// From: https://stackoverflow.com/questions/67062207/how-to-pan-audio-sample-data-naturally
sin_pan=arm_sin_f32(mapfloat(panorama[channel], MIN_PANORAMA, MAX_PANORAMA, 0.0, M_PI/2.0));
cos_pan=arm_cos_f32(mapfloat(panorama[channel], MIN_PANORAMA, MAX_PANORAMA, 0.0, M_PI/2.0));
// left
arm_scale_f32(in, sin_pan, tmp, buffer_length);
if(multiplier[channel]!=UNITY_GAIN)
arm_scale_f32(tmp,multiplier[channel],tmp,buffer_length);
arm_add_f32(sumbufL, tmp, sumbufL, buffer_length);
// right
arm_scale_f32(in, cos_pan, tmp, buffer_length);
if(multiplier[channel]!=UNITY_GAIN)
arm_scale_f32(tmp,multiplier[channel],tmp,buffer_length);
arm_add_f32(sumbufR, tmp, sumbufR, buffer_length);
}
void doAddMix(uint8_t channel, float32_t* inL, float32_t* inR)
{
float32_t tmp[buffer_length];
assert(inL);
assert(inR);
// left
if(multiplier[channel]!=UNITY_GAIN)
arm_scale_f32(inL,multiplier[channel],tmp,buffer_length);
arm_add_f32(sumbufL, tmp, sumbufL, buffer_length);
// right
if(multiplier[channel]!=UNITY_GAIN)
arm_scale_f32(inR,multiplier[channel],tmp,buffer_length);
arm_add_f32(sumbufR, tmp, sumbufR, buffer_length);
}
void getMix(float32_t* bufferL, float32_t* bufferR)
{
assert(bufferR);
assert(bufferL);
assert(sumbufL);
assert(sumbufR);
arm_copy_f32 (sumbufL, bufferL, buffer_length);
arm_copy_f32 (sumbufR, bufferR, buffer_length);
if(sumbufL)
arm_fill_f32(0.0f, sumbufL, buffer_length);
if(sumbufR)
arm_fill_f32(0.0f, sumbufR, buffer_length);
}
protected:
using AudioMixer<NN>::sumbufL;
using AudioMixer<NN>::multiplier;
using AudioMixer<NN>::buffer_length;
float32_t panorama[NN];
float32_t* sumbufR;
};
#endif