Capelets/audio-expander/render.cpp

This example shows you how to read from the extra audio channels of the audio expander capelet.

/*
 ____  _____ _        _
| __ )| ____| |      / \
|  _ \|  _| | |     / _ \
| |_) | |___| |___ / ___ \
|____/|_____|_____/_/   \_\
http://bela.io
*/
#include <Bela.h>
#include <cmath>

float gPhase[10] = {0};
float gFreq[10];
float inAcc[10] = {0};
unsigned int inAccCount[10] = {0};

bool setup(BelaContext *context, void *userData)
{
        float baseFreq = 123;
        for(unsigned int ch = 0; ch < context->audioOutChannels + context->analogOutChannels; ++ch)
                gFreq[ch] = baseFreq * (1 + ch);
        return true;
}

void render(BelaContext *context, void *userData)
{
        // process the audio channels
        for(unsigned int n = 0; n < context->audioFrames; ++n)
        {
                for(unsigned int ch = 0; ch < context->audioOutChannels; ++ch)
                {
                        float in = audioRead(context, n, ch);
                        inAcc[ch] += in;
                        ++inAccCount[ch];

                        float out = 0.4f * sinf(gPhase[ch]);
                        gPhase[ch] += 2.f * (float)M_PI * gFreq[ch] / context->audioSampleRate;
                        if(gPhase[ch] > M_PI)
                                gPhase[ch] -= 2.f * (float)M_PI;
                        audioWrite(context, n, ch, out);
                }
        }

        // process the analog channels
        for(unsigned int n = 0; n < context->analogFrames; ++n)
        {
                for(unsigned int ch = 0; ch < context->analogInChannels; ++ch)
                {
                        int idx = ch + context->audioOutChannels;
                        float in = analogRead(context, n, ch);
                        inAcc[idx] += in;
                        ++inAccCount[idx];

                        // when using the capelet, the analog output is AC-coupled,
                        // so we center it around 0, exactly the same as for the audio out
                        float out = 0.4f * sinf(gPhase[idx]);
                        // use the analogSampleRate instead
                        gPhase[idx] += 2.f * (float)M_PI * gFreq[idx] / context->analogSampleRate;
                        if(gPhase[idx] > (float)M_PI)
                                gPhase[idx] -= 2.f * (float)M_PI;
                        analogWriteOnce(context, n, ch, out);
                }
        }

        static int count = 0;
        for(unsigned int n = 0; n < context->audioFrames; ++n)
        {
                count += 1;
                if(count % (int)(context->audioSampleRate * 0.5f) == 0)
                {
                        rt_printf("Average input:\n");
                        for(unsigned int n = 0; n < 10; ++n)
                        {
                                rt_printf("[%d]:\t%.3f\t", n, inAcc[n]/inAccCount[n]);
                                if(n % 2 == 1)
                                        rt_printf("\n");
                        }
                }
        }

}

void cleanup(BelaContext *context, void *userData)
{

}