annotate projects/audio_in_FFT/render.cpp @ 39:638bc1ae2500 staging

Improved readibility of the DIGITAL code in the PRU, using register names instead of aliases and expanding some of the macros, removing unused macros. Binaries were not modified

/*
 * render.cpp
 *
 *  Created on: Oct 24, 2014
 *      Author: parallels
 */


#include "../../include/render.h"
#include <rtdk.h>
#include <NE10.h>					// neon library
#include <cmath>

int gFFTSize;
float gFFTScaleFactor = 0;

int gReadPointer = 0;
int gWritePointer = 0;

// FFT vars
ne10_fft_cpx_float32_t* timeDomainIn;
ne10_fft_cpx_float32_t* timeDomainOut;
ne10_fft_cpx_float32_t* frequencyDomain;
ne10_fft_cfg_float32_t cfg;

// initialise_render() is called once before the audio rendering starts.
// Use it to perform any initialisation and allocation which is dependent
// on the period size or sample rate.
//
// userData holds an opaque pointer to a data structure that was passed
// in from the call to initAudio().
//
// Return true on success; returning false halts the program.

bool initialise_render(int numMatrixChannels, int numAudioChannels,
					   int numMatrixFramesPerPeriod,
					   int numAudioFramesPerPeriod,
					   float matrixSampleRate, float audioSampleRate,
					   void *userData)
{
	// Retrieve a parameter passed in from the initAudio() call
	gFFTSize = *(int *)userData;
	gFFTScaleFactor = 1.0f / (float)gFFTSize;

	timeDomainIn = (ne10_fft_cpx_float32_t*) NE10_MALLOC (gFFTSize * sizeof (ne10_fft_cpx_float32_t));
	timeDomainOut = (ne10_fft_cpx_float32_t*) NE10_MALLOC (gFFTSize * sizeof (ne10_fft_cpx_float32_t));
	frequencyDomain = (ne10_fft_cpx_float32_t*) NE10_MALLOC (gFFTSize * sizeof (ne10_fft_cpx_float32_t));
	cfg = ne10_fft_alloc_c2c_float32 (gFFTSize);

	memset(timeDomainOut, 0, gFFTSize * sizeof (ne10_fft_cpx_float32_t));

	return true;
}

// render() is called regularly at the highest priority by the audio engine.
// Input and output are given from the audio hardware and the other
// ADCs and DACs (if available). If only audio is available, numMatrixFrames
// will be 0.

void render(int numMatrixFrames, int numAudioFrames, float *audioIn, float *audioOut,
			uint16_t *matrixIn, uint16_t *matrixOut)
{
	for(int n = 0; n < numAudioFrames; n++) {
		timeDomainIn[gReadPointer].r = (ne10_float32_t) ((audioIn[n*gNumAudioChannels] + audioIn[n*gNumAudioChannels+1]) * 0.5);
		timeDomainIn[gReadPointer].i = 0;

		if(++gReadPointer >= gFFTSize)
		{
			//FFT
			ne10_fft_c2c_1d_float32_neon (frequencyDomain, timeDomainIn, cfg->twiddles, cfg->factors, gFFTSize, 0);

			//Do frequency domain stuff

			//IFFT
			ne10_fft_c2c_1d_float32_neon (timeDomainOut, frequencyDomain, cfg->twiddles, cfg->factors, gFFTSize, 1);

			gReadPointer = 0;
			gWritePointer = 0;
		}

		for(int channel = 0; channel < gNumAudioChannels; channel++)
			audioOut[n * gNumAudioChannels + channel] = (float) timeDomainOut[gWritePointer].r * gFFTScaleFactor;
		gWritePointer++;
	}
}

// cleanup_render() is called once at the end, after the audio has stopped.
// Release any resources that were allocated in initialise_render().

void cleanup_render()
{
	NE10_FREE(timeDomainIn);
	NE10_FREE(timeDomainOut);
	NE10_FREE(frequencyDomain);
	NE10_FREE(cfg);
}