changeset 269:ac8eb07afcf5

Oxygen text added to each render.cpp file for the default projects. Text includes project explanation from Wiki, edited in places.

Empty project added as a default project.

Doxyfile updated. Each of the project locations added to INPUT configuration option. Consider just watching the whole project file so all new projects are automatically pulled through.

--- a/Doxyfile	Wed May 11 10:29:23 2016 +0100
+++ b/Doxyfile	Tue May 17 15:40:16 2016 +0100
@@ -648,7 +648,7 @@
 # directories like "/usr/src/myproject". Separate the files or directories
 # with spaces.
 
-INPUT                  =	include/BeagleRT.h include/Utilities.h include/digital_gpio_mapping.h include/PulseIn.h include/Scope.h include/Midi.h include/UdpClient.h include/WriteFile.h
+INPUT                  =	include/BeagleRT.h include/Utilities.h include/digital_gpio_mapping.h include/PulseIn.h include/Scope.h include/Midi.h include/UdpClient.h include/WriteFile.h projects/basic/render.cpp projects/basic_analog_input/render.cpp projects/basic_passthru/render.cpp projects/basic_blink/render.cpp projects/basic_button/render.cpp projects/basic_analog_output/render.cpp projects/samples/render.cpp projects/audio_in_FFT/render.cpp projects/basic_FFT_phase_vocoder/render.cpp projects/oscillator_bank/render.cpp projects/empty_project/render.cpp projects/analogDigitalDemo/render.cpp projects/basic_network/render.cpp
 
 # This tag can be used to specify the character encoding of the source files
 # that doxygen parses. Internally doxygen uses the UTF-8 encoding, which is
@@ -715,7 +715,7 @@
 # and *.h) to filter out the source-files in the directories. If left
 # blank all files are included.
 
-EXAMPLE_PATTERNS       =
+EXAMPLE_PATTERNS       = 
 
 # If the EXAMPLE_RECURSIVE tag is set to YES then subdirectories will be
 # searched for input files to be used with the \include or \dontinclude

--- a/projects/analogDigitalDemo/render.cpp	Wed May 11 10:29:23 2016 +0100
+++ b/projects/analogDigitalDemo/render.cpp	Tue May 17 15:40:16 2016 +0100
@@ -1,9 +1,35 @@
-    /*
+/*
+ ____  _____ _        _    
+| __ )| ____| |      / \   
+|  _ \|  _| | |     / _ \  
+| |_) | |___| |___ / ___ \ 
+|____/|_____|_____/_/   \_\.io
+
+ */
+
+/*
  *
  * Andrew McPherson and Victor Zappi
  * Queen Mary, University of London
  */
 
+/**
+\example 3_analogDigitalDemo
+
+Analog digital workout
+----------------------
+
+This sketch showcases many different ways to write and read digital pins, 
+including generating clocks and creating binary counters.
+
+The code as it is will not work properly, as the direction of the pins is not 
+set. As an exercise, you will need to set the pin mode before writing or reading 
+the digital pins. 
+
+This is for advanced users only.
+
+*/
+
 #include <BeagleRT.h>
 #include <Utilities.h>
 #include <cmath>

--- a/projects/audio_in_FFT/render.cpp	Wed May 11 10:29:23 2016 +0100
+++ b/projects/audio_in_FFT/render.cpp	Tue May 17 15:40:16 2016 +0100
@@ -1,3 +1,12 @@
+/*
+ ____  _____ _        _    
+| __ )| ____| |      / \   
+|  _ \|  _| | |     / _ \  
+| |_) | |___| |___ / ___ \ 
+|____/|_____|_____/_/   \_\.io
+
+ */
+
 /*
  * render.cpp
  *
@@ -5,6 +14,31 @@
  *      Author: parallels
  */
 
+/**
+\example 4_audio_FFT
+
+Fast Fourier Transform
+----------------------
+
+This sketch performs an FFT (Fast Fourier Transform) on incoming audio. It uses 
+the NE10 library, included at the top of the file (line 11).
+
+Read the documentation on the NE10 library [here](http://projectne10.github.io/Ne10/doc/annotated.html).
+
+The variables `timeDomainIn`, `timeDomainOut` and `frequencyDomain` are 
+variables of the struct `ne10_fft_cpx_float32_t` [http://projectne10.github.io/Ne10/doc/structne10__fft__cpx__float32__t.html](http://projectne10.github.io/Ne10/doc/structne10__fft__cpx__float32__t.html). 
+These are declared at the top of the file (line 21), and memory is allocated 
+for them in `setup()` (line 41).
+
+In `render()` a `for` loop performs the FFT which is performed on each sample, 
+and the resulting output is placed on each channel.
+
+*/
+
+
+
+
+
 
 #include <BeagleRT.h>
 #include <rtdk.h>

--- a/projects/basic/render.cpp	Wed May 11 10:29:23 2016 +0100
+++ b/projects/basic/render.cpp	Tue May 17 15:40:16 2016 +0100
@@ -1,3 +1,12 @@
+/*
+ ____  _____ _        _    
+| __ )| ____| |      / \   
+|  _ \|  _| | |     / _ \  
+| |_) | |___| |___ / ___ \ 
+|____/|_____|_____/_/   \_\.io
+
+ */
+
 /*
  * render.cpp
  *
@@ -5,6 +14,26 @@
  *      Author: parallels
  */
 
+/**
+\example 1_basic_helloworld
+
+Producing your first bleep!
+---------------------------
+
+This sketch is the hello world of embedded interactive audio. Better known as bleep, it 
+produces a sine tone.
+
+The frequency of the sine tone is determined by a global variable, `gFrequency` 
+(line 12). The sine tone is produced by incrementing the phase of a sin function 
+on every audio frame.
+
+The important thing to notice is the nested `for` loop structure. You will see 
+this in all Bela projects and in most digital audio applications. The first `for`
+loop cycles through the audio frames, the second through each of the audio
+channels (in this case left 0 and right 1). It is good to familiarise yourself
+with this structure as it is fundamental to producing sound with the system.
+*/
+
 
 #include <BeagleRT.h>
 #include <cmath>
@@ -22,7 +51,6 @@
 // in from the call to initAudio().
 //
 // Return true on success; returning false halts the program.
-
 bool setup(BeagleRTContext *context, void *userData)
 {
 	// Retrieve a parameter passed in from the initAudio() call

--- a/projects/basic_FFT_phase_vocoder/render.cpp	Wed May 11 10:29:23 2016 +0100
+++ b/projects/basic_FFT_phase_vocoder/render.cpp	Tue May 17 15:40:16 2016 +0100
@@ -1,3 +1,12 @@
+/*
+ ____  _____ _        _    
+| __ )| ____| |      / \   
+|  _ \|  _| | |     / _ \  
+| |_) | |___| |___ / ___ \ 
+|____/|_____|_____/_/   \_\.io
+
+ */
+
 /*
  * render.cpp
  *
@@ -5,6 +14,19 @@
  *      Author: parallels
  */
 
+/**
+\example 4_audio_FFT_phase_vocoder
+
+Phase Vocoder
+----------------------
+
+This sketch shows an implementation of a phase vocoder and builds on the previous FFT example.
+Again it uses the NE10 library, included at the top of the file (line 11).
+
+Read the documentation on the NE10 library [here](http://projectne10.github.io/Ne10/doc/annotated.html).
+
+*/
+
 
 #include <BeagleRT.h>
 #include <rtdk.h>

--- a/projects/basic_analog_input/render.cpp	Wed May 11 10:29:23 2016 +0100
+++ b/projects/basic_analog_input/render.cpp	Tue May 17 15:40:16 2016 +0100
@@ -1,3 +1,12 @@
+/*
+ ____  _____ _        _    
+| __ )| ____| |      / \   
+|  _ \|  _| | |     / _ \  
+| |_) | |___| |___ / ___ \ 
+|____/|_____|_____/_/   \_\.io
+
+ */
+
 /*
  * render.cpp
  *
@@ -5,6 +14,30 @@
  *      Author: parallels
  */
 
+/**
+\example 3_analog_input
+
+Connecting potentiometers
+-------------------------
+
+This sketch produces a sine tone, the frequency and amplitude of which are 
+affected by data received on the analog pins. Before looping through each audio 
+frame, we declare a value for the frequency and amplitude of our sine tone 
+(line 55); we adjust these values by taking in data from analog sensors 
+(for example, a potentiometer).
+
+The important thing to notice is that audio is sampled twice as often as analog 
+data. The audio sampling rate is 44.1kHz (44100 frames per second) and the 
+analog sampling rate is 22.05kHz (22050 frames per second). On line 62 you might 
+notice that we are processing the analog data and updating frequency and 
+amplitude only on every second audio sample, since the analog sampling rate is 
+half that of the audio.
+
+Note that the pin numbers are stored in the variables `gAnalogInputFrequency` and 
+`gAnalogInputAmplitude`. These are declared in the main.cpp file; if you look in 
+that file you will see that they have the values of 0 and 1. Bear in mind that 
+these are analog input pins which is a specific header!
+*/
 
 #include <BeagleRT.h>
 #include <Utilities.h>
@@ -31,6 +64,7 @@
 //
 // Return true on success; returning false halts the program.
 
+
 bool setup(BeagleRTContext *context, void *userData)
 {
 	if(context->analogFrames == 0 || context->analogFrames > context->audioFrames) {

--- a/projects/basic_analog_output/render.cpp	Wed May 11 10:29:23 2016 +0100
+++ b/projects/basic_analog_output/render.cpp	Tue May 17 15:40:16 2016 +0100
@@ -1,10 +1,48 @@
 /*
- * render.cpp
+ ____  _____ _        _    
+| __ )| ____| |      / \   
+|  _ \|  _| | |     / _ \  
+| |_) | |___| |___ / ___ \ 
+|____/|_____|_____/_/   \_\.io
+
+ */
+
+/*
  *
- *  Created on: Oct 24, 2014
- *      Author: parallels
+ * Andrew McPherson and Victor Zappi
+ * Queen Mary, University of London
  */
 
+/**
+\example 3_analog_output
+
+Fading LEDs
+-----------
+
+This sketch uses a sine wave to drive the brightness of a series of LEDs 
+connected to the eight analog out pins. Again you can see the nested `for` loop 
+structure but this time for the analog output channels rather than the audio.
+
+Within the first `for` loop in render we cycle through each frame in the analog 
+output matrix. At each frame we then cycle through the analog output channels 
+with another `for` loop and set the output voltage according to the phase of a 
+sine tone that acts as an LFO. The analog output pins can provide a voltage of 
+~4.092V.
+
+The output on each pin is set with `analogWriteFrame` within the `for` loop that 
+cycles through the analog output channels. This needs to be provided with 
+arguments as follows `analogWriteFrame(context, n, channel, out)`. Channel is 
+where the you give the address of the analog output pin (in this case we cycle 
+through each pin address in the for loop), out is the variable that holds the 
+desired output (in this case set by the sine wave).
+
+Notice that the phase of the brightness cycle for each led is different. This 
+is achieved by updating a variable that stores a relative phase value. This 
+variable is advanced by pi/4 (1/8 of a full rotation) for each channel giving 
+each of the eight LEDs a different phase.
+
+*/
+
 
 #include <BeagleRT.h>
 #include <Utilities.h>

--- a/projects/basic_blink/render.cpp	Wed May 11 10:29:23 2016 +0100
+++ b/projects/basic_blink/render.cpp	Tue May 17 15:40:16 2016 +0100
@@ -1,3 +1,46 @@
+/*
+ ____  _____ _        _    
+| __ )| ____| |      / \   
+|  _ \|  _| | |     / _ \  
+| |_) | |___| |___ / ___ \ 
+|____/|_____|_____/_/   \_\.io
+
+ */
+
+/*
+ *
+ * Andrew McPherson and Victor Zappi
+ * Queen Mary, University of London
+ */
+
+/**
+\example 2_digital_blink
+
+Blinking an LED
+---------------
+
+This sketch shows the simplest case of digital out. Connect an LED in series with
+a 470ohm resistor between P8_07 and ground. The led is blinked on and off by 
+setting the digital pin `HIGH` and `LOW` every interval seconds (set it in the 
+`render()` function).
+
+Firstly the pin mode must be set to output mode: 
+`pinModeFrame(context, 0, P8_07, OUTPUT);` in the `setup()` function. The output 
+of the digital pins is set by the following code: 
+`digitalWriteFrame(context, n, P8_07, status);` where status can be equal to 
+either `HIGH` or `LOW`. When set `HIGH` the pin will give 3.3V, when set to 
+`LOW` 0V.
+
+To keep track of elapsed time we have a sample counter count. When count reaches 
+a certain limit it switches state to either `HIGH` or `LOW` depending on its current 
+value. In this case the limit is `context->digitalSampleRate*interval` which 
+allows us to write the desired interval in seconds, stored in `interval`.
+*/
+
+
+
+
+
 #include <BeagleRT.h>
 #include <Utilities.h>
 #include <cmath>

--- a/projects/basic_button/render.cpp	Wed May 11 10:29:23 2016 +0100
+++ b/projects/basic_button/render.cpp	Tue May 17 15:40:16 2016 +0100
@@ -1,9 +1,43 @@
+/*
+ ____  _____ _        _    
+| __ )| ____| |      / \   
+|  _ \|  _| | |     / _ \  
+| |_) | |___| |___ / ___ \ 
+|____/|_____|_____/_/   \_\.io
+
+ */
+
 /*
  *
  * Andrew McPherson and Victor Zappi
  * Queen Mary, University of London
  */
 
+/**
+\example 2_digital_button
+
+Switching an LED on and off
+---------------------------
+
+This sketch brings together digital out with digital in. The program will read 
+a button and turn the LED on and off according to the state of the button.
+
+- connect an LED in series with a 470ohm resistor between P8_07 and ground.
+- connect a 1k resistor to P9_03 (+3.3V),
+- connect the other end of the resistor to both a button and P8_08
+- connect the other end of the button to ground.
+
+You will notice that the LED will normally stay on and will turn off as long as 
+the button is pressed. This is due to the fact that the LED is set to the same 
+value read at input P8_08. When the button is not pressed, P8_08 is `HIGH` and so 
+P8_07 is set to `HIGH` as well, so that the LED conducts and emits light. When 
+the button is pressed, P8_08 goes `LOW` and P8_07 is set to `LOW`, turning off the LED.
+
+As an exercise try and change the code so that the LED only turns on when 
+the button is pressed
+*/
+
+
 #include <BeagleRT.h>
 #include <Utilities.h>
 #include <cmath>

--- a/projects/basic_network/render.cpp	Wed May 11 10:29:23 2016 +0100
+++ b/projects/basic_network/render.cpp	Tue May 17 15:40:16 2016 +0100
@@ -1,3 +1,12 @@
+/*
+ ____  _____ _        _    
+| __ )| ____| |      / \   
+|  _ \|  _| | |     / _ \  
+| |_) | |___| |___ / ___ \ 
+|____/|_____|_____/_/   \_\.io
+
+*/
+
 /*
  * render.cpp
  *
@@ -5,6 +14,20 @@
  *      Author: parallels
  */
 
+/**
+\example 5_basic_network
+
+Networking 
+----------
+
+This sketch allows you to send audio and sensor data over UDP to a 
+DAW on the host. The host needs to run Udpioplugin which you can f
+ind [here](https://code.soundsoftware.ac.uk/projects/udpioplugin). 
+
+Note that this sketch and the accompanying plugin are still in testing.
+
+*/
+
 #include <BeagleRT.h>
 //#include <rtdk.h>
 #include <cmath>

--- a/projects/basic_passthru/render.cpp	Wed May 11 10:29:23 2016 +0100
+++ b/projects/basic_passthru/render.cpp	Tue May 17 15:40:16 2016 +0100
@@ -1,10 +1,50 @@
 /*
+ ____  _____ _        _    
+| __ )| ____| |      / \   
+|  _ \|  _| | |     / _ \  
+| |_) | |___| |___ / ___ \ 
+|____/|_____|_____/_/   \_\.io
+
+ */
+
+ /*
  * render.cpp
  *
  *  Created on: Oct 24, 2014
  *      Author: parallels
  */
 
+/**
+\example 1_basic_audio_passthrough
+
+Audio passthrough: input to output
+-----------------------------------------
+
+This sketch demonstrates the simplest possible case of using audio: it passes 
+audio input straight to audio output.
+
+Note the nested `for` loop structure. You will see this in all Bela projects. The 
+first `for` loop cycles through the audio frames, the second through each of the 
+audio channels (in this case left 0 and right 1).
+
+
+We write samples to the audio output buffer like this: 
+`context->audioOut[n * context->audioChannels + ch]` where `n` is the current audio 
+frame and `ch` is the current channel, both provided by the nested for loop structure.
+
+We can access samples in the audio input buffer in a similar way, like this: 
+`context->audioIn[n * context->audioChannels + ch]`.
+
+So a simple audio pass through is achieved by setting output buffer equal to 
+input buffer: 
+`context->audioOut[n * context->audioChannels + ch] = context->audioIn[n * context->audioChannels + ch]`.
+
+
+*/
+
+
+
+
 
 #include <BeagleRT.h>
 #include <Utilities.h>

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/projects/empty_project/main.cpp	Tue May 17 15:40:16 2016 +0100
@@ -0,0 +1,96 @@
+/*
+ * default_main.cpp
+ *
+ *  Created on: Oct 24, 2014
+ *      Author: parallels
+ */
+//#include <unistd.h>
+#include <iostream>
+#include <cstdlib>
+#include <libgen.h>
+#include <signal.h>
+#include <getopt.h>
+#include "../include/BeagleRT.h"
+
+using namespace std;
+
+int returnCode = 0;
+
+// Handle Ctrl-C by requesting that the audio rendering stop
+void interrupt_handler(int var)
+{
+	gShouldStop = true;
+	// allows other process to monitor why beagleRT has exited
+	// var=15, returnCode = 143 if terminated with SIGTERM
+	returnCode = var + 128;
+}
+
+// Print usage information
+void usage(const char * processName)
+{
+	cerr << "Usage: " << processName << " [options]" << endl;
+
+	BeagleRT_usage();
+
+	cerr << "   --help [-h]:                Print this menu\n";
+}
+
+int main(int argc, char *argv[])
+{
+	BeagleRTInitSettings settings;	// Standard audio settings
+
+	struct option customOptions[] =
+	{
+		{"help", 0, NULL, 'h'},
+		{NULL, 0, NULL, 0}
+	};
+
+	// Set default settings
+	BeagleRT_defaultSettings(&settings);
+
+	// Parse command-line arguments
+	while (1) {
+		int c;
+		if ((c = BeagleRT_getopt_long(argc, argv, "h", customOptions, &settings)) < 0)
+				break;
+		switch (c) {
+		case 'h':
+				usage(basename(argv[0]));
+				exit(0);
+		case '?':
+		default:
+				usage(basename(argv[0]));
+				exit(1);
+		}
+	}
+
+	// Initialise the PRU audio device
+	if(BeagleRT_initAudio(&settings, 0) != 0) {
+		cout << "Error: unable to initialise audio" << endl;
+		return -1;
+	}
+
+	// Start the audio device running
+	if(BeagleRT_startAudio()) {
+		cout << "Error: unable to start real-time audio" << endl;
+		return -1;
+	}
+
+	// Set up interrupt handler to catch Control-C and SIGTERM
+	signal(SIGINT, interrupt_handler);
+	signal(SIGTERM, interrupt_handler);
+
+	// Run until told to stop
+	while(!gShouldStop) {
+		usleep(100000);
+	}
+
+	// Stop the audio device
+	BeagleRT_stopAudio();
+
+	// Clean up any resources allocated for audio
+	BeagleRT_cleanupAudio();
+
+	// All done!
+	return returnCode;
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/projects/empty_project/render.cpp	Tue May 17 15:40:16 2016 +0100
@@ -0,0 +1,112 @@
+/*
+ ____  _____ _        _    
+| __ )| ____| |      / \   
+|  _ \|  _| | |     / _ \  
+| |_) | |___| |___ / ___ \ 
+|____/|_____|_____/_/   \_\.io
+
+*/
+
+/**
+\example 1_empty_project
+
+The bare bones
+----------------------
+
+The structure of a render.cpp file
+----------------------------------
+A render.cpp file has three functions: `setup()`, `render()` and `cleanup()`.
+
+`setup()` is an initialisation function which runs before audio rendering begins. 
+It is called once when the project starts. Use it to prepare any memory or 
+resources that will be needed in `render()`.
+
+`render()` is a function that is regularly called, over and over continuously, at 
+the highest priority by the audio engine. It is used to process audio and 
+sensor data. This function is called regularly by the system every time there 
+is a new block of audio and/or sensor data to process.
+
+`cleanup()` is a function that is called when the program stops, to finish up any 
+processes that might still be running.
+
+Here we will briefly explain each function and the structure of the render.cpp 
+
+Before any of the functions
+---------------------------
+At the top of the file, include any libraries you might need.
+
+Additionally, declare any global variables. In these tutorial sketches, all 
+global variables are preceded by a `g` so we always know which variables are 
+global - `gSampleData`, for example. It's not mandatory but is a really good way 
+of keeping track of what's global and what's not.
+
+Sometimes it's necessary to access a variable from another file, such as 
+main.cpp. In this case, precede this variable with the keyword `extern`.
+
+Function arguments
+------------------
+`setup()`, `render()` and `cleanup()` each take the same arguments. These are:
+
+`0ext *context`
+`void *userData`
+
+These arguments are pointers to data structures. The main one that's used is 
+`context`, which is a pointer to a data structure containing lots of information 
+you need.
+
+Take a look at what's in the data structure [here]
+(https://code.soundsoftware.ac.uk/projects/beaglert/embedded/structBeagleRTContext.html).
+
+You can access any of these bits of information about current audio and sensor 
+settings and pointers to data buffers that are contained in the data structure 
+like this: `context->name_of_item`.
+
+For example, `context->audioChannels` returns the number of audio channels. 
+`context->audioSampleRate` returns the audio sample rate. 
+`context->audioIn[n]` would give you the current input sample (assuming that 
+your input is mono - if it's not you will have to account for multiple channels).
+
+Note that `audioIn`, `audioOut`, `analogIn`, `analogOut` are all arrays (buffers).
+
+*/
+
+
+
+
+#include <BeagleRT.h>
+#include <Utilities.h>
+#include <rtdk.h>
+#include <cmath>
+
+// setup() 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 setup(BeagleRTContext *context, void *userData)
+{
+
+	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(BeagleRTContext *context, void *userData)
+{
+
+}
+
+// cleanup() is called once at the end, after the audio has stopped.
+// Release any resources that were allocated in setup().
+
+void cleanup(BeagleRTContext *context, void *userData)
+{
+
+}

--- a/projects/oscillator_bank/render.cpp	Wed May 11 10:29:23 2016 +0100
+++ b/projects/oscillator_bank/render.cpp	Tue May 17 15:40:16 2016 +0100
@@ -1,3 +1,12 @@
+/*
+ ____  _____ _        _    
+| __ )| ____| |      / \   
+|  _ \|  _| | |     / _ \  
+| |_) | |___| |___ / ___ \ 
+|____/|_____|_____/_/   \_\.io
+
+ */
+
 /*
  * render.cpp
  *
@@ -5,6 +14,18 @@
  *      Author: parallels
  */
 
+/**
+\example 4_oscillator_bank
+
+Oscillator Bank
+----------------------
+
+These files demonstrate an oscillator bank implemented in assembly code 
+that is used as part of the d-box project.
+
+
+*/
+
 
 #include <BeagleRT.h>
 #include <Utilities.h>

--- a/projects/samples/render.cpp	Wed May 11 10:29:23 2016 +0100
+++ b/projects/samples/render.cpp	Tue May 17 15:40:16 2016 +0100
@@ -1,10 +1,44 @@
 /*
- * render.cpp
+ ____  _____ _        _    
+| __ )| ____| |      / \   
+|  _ \|  _| | |     / _ \  
+| |_) | |___| |___ / ___ \ 
+|____/|_____|_____/_/   \_\.io
+
+ */
+
+/*
  *
- *  Created on: Oct 24, 2014
- *      Author: Andrew McPherson and Victor Zappi
+ * Andrew McPherson and Victor Zappi
+ * Queen Mary, University of London
  */
 
+/**
+\example 4_audio_samples
+
+Playback WAV files
+------------------
+
+This sketch shows how to playback audio samples from a buffer.
+
+An audio file is loaded into a buffer `SampleData` as `gSampleData`. This is 
+accessed with a read pointer that is incremented at audio rate within the render 
+function: `out += gSampleData.samples[gReadPtr++]`.
+
+Note that the read pointer is stopped from incrementing past the length of the 
+`gSampleData`. This is achieved by comparing the read pointer value against the 
+sample length which we can access as follows: `gSampleData.sampleLen`.
+
+The sample is triggered by keyboard input: (a) starts sample playback, (s) 
+stops sample playback. The triggering is treated as a lower priority task than 
+the audio. You can see this at the bottom of the render function: 
+`Bela_scheduleAuxiliaryTask(gTriggerSamplesTask)`;
+
+Edit
+
+*/
+
+
 
 #include <BeagleRT.h>
 #include <cmath>