robert@464: /*
robert@464: ____ _____ _ _
robert@464: | __ )| ____| | / \
robert@464: | _ \| _| | | / _ \
robert@464: | |_) | |___| |___ / ___ \
robert@464: |____/|_____|_____/_/ \_\
robert@464:
robert@464: The platform for ultra-low latency audio and sensor processing
robert@464:
robert@464: http://bela.io
robert@464:
robert@464: A project of the Augmented Instruments Laboratory within the
robert@464: Centre for Digital Music at Queen Mary University of London.
robert@464: http://www.eecs.qmul.ac.uk/~andrewm
robert@464:
robert@464: (c) 2016 Augmented Instruments Laboratory: Andrew McPherson,
robert@464: Astrid Bin, Liam Donovan, Christian Heinrichs, Robert Jack,
robert@464: Giulio Moro, Laurel Pardue, Victor Zappi. All rights reserved.
robert@464:
robert@464: The Bela software is distributed under the GNU Lesser General Public License
robert@464: (LGPL 3.0), available here: https://www.gnu.org/licenses/lgpl-3.0.txt
robert@464: */
robert@464:
robert@464:
robert@464: #include <Bela.h>
robert@464: #include <rtdk.h>
robert@464: #include <cstdlib>
robert@464: #include <cmath>
robert@464: #include <cstring>
robert@464: #include <time.h>
robert@464:
robert@464: const float kMinimumFrequency = 20.0f;
robert@464: const float kMaximumFrequency = 8000.0f;
robert@464:
robert@464: float *gWavetable; // Buffer holding the precalculated sine lookup table
robert@464: float *gPhases; // Buffer holding the phase of each oscillator
robert@464: float *gFrequencies; // Buffer holding the frequencies of each oscillator
robert@464: float *gAmplitudes; // Buffer holding the amplitudes of each oscillator
robert@464: float *gDFrequencies; // Buffer holding the derivatives of frequency
robert@464: float *gDAmplitudes; // Buffer holding the derivatives of amplitude
robert@464:
robert@464: float gAudioSampleRate;
robert@464: int gSampleCount; // Sample counter for indicating when to update frequencies
robert@464: float gNewMinFrequency;
robert@464: float gNewMaxFrequency;
robert@464:
robert@464: // Task for handling the update of the frequencies using the matrix
robert@464: AuxiliaryTask gFrequencyUpdateTask;
robert@464:
robert@464: // These settings are carried over from main.cpp
robert@464: // Setting global variables is an alternative approach
robert@464: // to passing a structure to userData in setup()
robert@464:
robert@464: extern int gNumOscillators;
robert@464: extern int gWavetableLength;
robert@464:
robert@464: void recalculate_frequencies();
robert@464:
robert@464: extern "C" {
robert@464: // Function prototype for ARM assembly implementation of oscillator bank
robert@464: void oscillator_bank_neon(int numAudioFrames, float *audioOut,
robert@464: int activePartialNum, int lookupTableSize,
robert@464: float *phases, float *frequencies, float *amplitudes,
robert@464: float *freqDerivatives, float *ampDerivatives,
robert@464: float *lookupTable);
robert@464: }
robert@464:
robert@464: // setup() is called once before the audio rendering starts.
robert@464: // Use it to perform any initialisation and allocation which is dependent
robert@464: // on the period size or sample rate.
robert@464: //
robert@464: // userData holds an opaque pointer to a data structure that was passed
robert@464: // in from the call to initAudio().
robert@464: //
robert@464: // Return true on success; returning false halts the program.
robert@464: bool setup(BelaContext *context, void *userData)
robert@464: {
robert@464: srandom(time(NULL));
robert@464:
robert@464: if(context->audioChannels != 2) {
robert@464: rt_printf("Error: this example needs stereo audio enabled\n");
robert@464: return false;
robert@464: }
robert@464:
robert@464: // Initialise the sine wavetable
robert@464: if(posix_memalign((void **)&gWavetable, 8, (gWavetableLength + 1) * sizeof(float))) {
robert@464: rt_printf("Error allocating wavetable\n");
robert@464: return false;
robert@464: }
robert@464: for(int n = 0; n < gWavetableLength + 1; n++)
robert@464: gWavetable[n] = sinf(2.0 * M_PI * (float)n / (float)gWavetableLength);
robert@464:
robert@464: // Allocate the other buffers
robert@464: if(posix_memalign((void **)&gPhases, 16, gNumOscillators * sizeof(float))) {
robert@464: rt_printf("Error allocating phase buffer\n");
robert@464: return false;
robert@464: }
robert@464: if(posix_memalign((void **)&gFrequencies, 16, gNumOscillators * sizeof(float))) {
robert@464: rt_printf("Error allocating frequency buffer\n");
robert@464: return false;
robert@464: }
robert@464: if(posix_memalign((void **)&gAmplitudes, 16, gNumOscillators * sizeof(float))) {
robert@464: rt_printf("Error allocating amplitude buffer\n");
robert@464: return false;
robert@464: }
robert@464: if(posix_memalign((void **)&gDFrequencies, 16, gNumOscillators * sizeof(float))) {
robert@464: rt_printf("Error allocating frequency derivative buffer\n");
robert@464: return false;
robert@464: }
robert@464: if(posix_memalign((void **)&gDAmplitudes, 16, gNumOscillators * sizeof(float))) {
robert@464: rt_printf("Error allocating amplitude derivative buffer\n");
robert@464: return false;
robert@464: }
robert@464:
robert@464: // Initialise buffer contents
robert@464:
robert@464: float freq = kMinimumFrequency;
robert@464: float increment = (kMaximumFrequency - kMinimumFrequency) / (float)gNumOscillators;
robert@464:
robert@464: for(int n = 0; n < gNumOscillators; n++) {
robert@464: gPhases[n] = 0.0;
robert@464:
robert@464: if(context->analogFrames == 0) {
robert@464: // Random frequencies when used without matrix
robert@464: gFrequencies[n] = kMinimumFrequency + (kMaximumFrequency - kMinimumFrequency) * ((float)random() / (float)RAND_MAX);
robert@464: }
robert@464: else {
robert@464: // Constant spread of frequencies when used with matrix
robert@464: gFrequencies[n] = freq;
robert@464: freq += increment;
robert@464: }
robert@464:
robert@464: // For efficiency, frequency is expressed in change in wavetable position per sample, not Hz or radians
robert@464: gFrequencies[n] *= (float)gWavetableLength / context->audioSampleRate;
robert@464: gAmplitudes[n] = ((float)random() / (float)RAND_MAX) / (float)gNumOscillators;
robert@464: gDFrequencies[n] = gDAmplitudes[n] = 0.0;
robert@464: }
robert@464:
robert@464: increment = 0;
robert@464: freq = 440.0;
robert@464:
robert@464: for(int n = 0; n < gNumOscillators; n++) {
robert@464: // Update the frequencies to a regular spread, plus a small amount of randomness
robert@464: // to avoid weird phase effects
robert@464: float randScale = 0.99 + .02 * (float)random() / (float)RAND_MAX;
robert@464: float newFreq = freq * randScale;
robert@464:
robert@464: // For efficiency, frequency is expressed in change in wavetable position per sample, not Hz or radians
robert@464: gFrequencies[n] = newFreq * (float)gWavetableLength / context->audioSampleRate;
robert@464:
robert@464: freq += increment;
robert@464: }
robert@464:
robert@464: // Initialise auxiliary tasks
robert@464: if((gFrequencyUpdateTask = Bela_createAuxiliaryTask(&recalculate_frequencies, 85, "bela-update-frequencies")) == 0)
robert@464: return false;
robert@464:
robert@464: //for(int n = 0; n < gNumOscillators; n++)
robert@464: // rt_printf("%f\n", gFrequencies[n]);
robert@464:
robert@464: gAudioSampleRate = context->audioSampleRate;
robert@464: gSampleCount = 0;
robert@464:
robert@464: return true;
robert@464: }
robert@464:
robert@464: // render() is called regularly at the highest priority by the audio engine.
robert@464: // Input and output are given from the audio hardware and the other
robert@464: // ADCs and DACs (if available). If only audio is available, numMatrixFrames
robert@464: // will be 0.
robert@464:
robert@464: void render(BelaContext *context, void *userData)
robert@464: {
robert@464: // Initialise buffer to 0
robert@464: memset(context->audioOut, 0, 2 * context->audioFrames * sizeof(float));
robert@464:
robert@464: // Render audio frames
robert@464: oscillator_bank_neon(context->audioFrames, context->audioOut,
robert@464: gNumOscillators, gWavetableLength,
robert@464: gPhases, gFrequencies, gAmplitudes,
robert@464: gDFrequencies, gDAmplitudes,
robert@464: gWavetable);
robert@464:
robert@464: if(context->analogFrames != 0 && (gSampleCount += context->audioFrames) >= 128) {
robert@464: gSampleCount = 0;
robert@464: gNewMinFrequency = map(context->analogIn[0], 0, 1.0, 1000.0f, 8000.0f);
robert@464: gNewMaxFrequency = map(context->analogIn[1], 0, 1.0, 1000.0f, 8000.0f);
robert@464:
robert@464: // Make sure max >= min
robert@464: if(gNewMaxFrequency < gNewMinFrequency) {
robert@464: float temp = gNewMaxFrequency;
robert@464: gNewMaxFrequency = gNewMinFrequency;
robert@464: gNewMinFrequency = temp;
robert@464: }
robert@464:
robert@464: // Request that the lower-priority task run at next opportunity
robert@464: //Bela_scheduleAuxiliaryTask(gFrequencyUpdateTask);
robert@464: }
robert@464: }
robert@464:
robert@464: // This is a lower-priority call to update the frequencies which will happen
robert@464: // periodically when the matrix is enabled. By placing it at a lower priority,
robert@464: // it has minimal effect on the audio performance but it will take longer to
robert@464: // complete if the system is under heavy audio load.
robert@464:
robert@464: void recalculate_frequencies()
robert@464: {
robert@464: float freq = gNewMinFrequency;
robert@464: float increment = (gNewMaxFrequency - gNewMinFrequency) / (float)gNumOscillators;
robert@464:
robert@464: for(int n = 0; n < gNumOscillators; n++) {
robert@464: // Update the frequencies to a regular spread, plus a small amount of randomness
robert@464: // to avoid weird phase effects
robert@464: float randScale = 0.99 + .02 * (float)random() / (float)RAND_MAX;
robert@464: float newFreq = freq * randScale;
robert@464:
robert@464: // For efficiency, frequency is expressed in change in wavetable position per sample, not Hz or radians
robert@464: gFrequencies[n] = newFreq * (float)gWavetableLength / gAudioSampleRate;
robert@464:
robert@464: freq += increment;
robert@464: }
robert@464: }
robert@464:
robert@464:
robert@464: // cleanup() is called once at the end, after the audio has stopped.
robert@464: // Release any resources that were allocated in setup().
robert@464:
robert@464: void cleanup(BelaContext *context, void *userData)
robert@464: {
robert@464: free(gWavetable);
robert@464: free(gPhases);
robert@464: free(gFrequencies);
robert@464: free(gAmplitudes);
robert@464: free(gDFrequencies);
robert@464: free(gDAmplitudes);
robert@464: }
robert@464:
robert@464: /* ------------ Project Explantation ------------ */
robert@464:
robert@464: /**
robert@464: \example 04-oscillator-bank
robert@464:
robert@464: Oscillator Bank
robert@464: ----------------------
robert@464:
robert@464: These files demonstrate an oscillator bank implemented in assembly code
robert@464: that is used as part of the d-box project.
robert@464: */