Gui/ambient-ellipse/render.cpp

Visualising a Low Frequency Oscillator

Is this project you can find a sketch.js file which is a p5.js file that is rendered in a browser tab. Click the GUI button (next to the Scope button) in the IDE to see the rendering of this file.

This example sends a buffer of data from the Bela render to the browser via a web socket every few milliseconds containing the value of a sinewave LFO: gui.sendBuffer(0, sineValue);

The p5.js file displays the position of the sinewave in two different ways.

/*
 ____  _____ _        _
| __ )| ____| |      / \
|  _ \|  _| | |     / _ \
| |_) | |___| |___ / ___ \
|____/|_____|_____/_/   \_\
http://bela.io
*/
 
#include <Bela.h>
#include <cmath>
#include <libraries/Gui/Gui.h>
 
Gui gui;
 
// variable for the Low Frequency Oscillator
float gFrequency = 0.1;
float gPhase;
float gInverseSampleRate;
 
// Array for sending to the GUI
float sineValue[] = {0.0};
 
// Time period (in seconds) after which data will be sent to the GUI
float gTimePeriod = 0.04;
 
bool setup(BelaContext *context, void *userData)
{
        gInverseSampleRate = 1.0 / context->audioSampleRate;
        gPhase = 0.0;
 
        gui.setup(context->projectName);
        return true;
}
 
void render(BelaContext *context, void *userData)
{
        for(unsigned int n = 0; n < context->audioFrames; n++) {
 
                float out = sinf(gPhase);
 
                gPhase += 2.0f * (float)M_PI * gFrequency * gInverseSampleRate;
                if(gPhase > M_PI)
                        gPhase -= 2.0f * (float)M_PI;
 
                static unsigned int count = 0;
                // After time period is elapsed send to GUI
                if (count >= gTimePeriod*context->audioSampleRate)
                {
                        count = 0;
                        // Update Array
                        sineValue[0] = out;
                        // Send to GUI
                        gui.sendBuffer(0, sineValue);
                }
                count++;
        }
}
 
 
void cleanup(BelaContext *context, void *userData)
{
 
}