robert@269: /*
robert@269:  ____  _____ _        _    
robert@269: | __ )| ____| |      / \   
robert@269: |  _ \|  _| | |     / _ \  
robert@269: | |_) | |___| |___ / ___ \ 
robert@269: |____/|_____|_____/_/   \_\.io
robert@269: 
robert@269: */
robert@269: 
robert@269: /**
robert@269: \example 1_empty_project
robert@269: 
robert@269: The bare bones
robert@269: ----------------------
robert@269: 
robert@269: The structure of a render.cpp file
robert@269: ----------------------------------
robert@269: A render.cpp file has three functions: `setup()`, `render()` and `cleanup()`.
robert@269: 
robert@269: `setup()` is an initialisation function which runs before audio rendering begins. 
robert@269: It is called once when the project starts. Use it to prepare any memory or 
robert@269: resources that will be needed in `render()`.
robert@269: 
robert@269: `render()` is a function that is regularly called, over and over continuously, at 
robert@269: the highest priority by the audio engine. It is used to process audio and 
robert@269: sensor data. This function is called regularly by the system every time there 
robert@269: is a new block of audio and/or sensor data to process.
robert@269: 
robert@269: `cleanup()` is a function that is called when the program stops, to finish up any 
robert@269: processes that might still be running.
robert@269: 
robert@269: Here we will briefly explain each function and the structure of the render.cpp 
robert@269: 
robert@269: Before any of the functions
robert@269: ---------------------------
robert@269: At the top of the file, include any libraries you might need.
robert@269: 
robert@269: Additionally, declare any global variables. In these tutorial sketches, all 
robert@269: global variables are preceded by a `g` so we always know which variables are 
robert@269: global - `gSampleData`, for example. It's not mandatory but is a really good way 
robert@269: of keeping track of what's global and what's not.
robert@269: 
robert@269: Sometimes it's necessary to access a variable from another file, such as 
robert@269: main.cpp. In this case, precede this variable with the keyword `extern`.
robert@269: 
robert@269: Function arguments
robert@269: ------------------
robert@269: `setup()`, `render()` and `cleanup()` each take the same arguments. These are:
robert@269: 
robert@269: `0ext *context`
robert@269: `void *userData`
robert@269: 
robert@269: These arguments are pointers to data structures. The main one that's used is 
robert@269: `context`, which is a pointer to a data structure containing lots of information 
robert@269: you need.
robert@269: 
robert@269: Take a look at what's in the data structure [here]
robert@269: (https://code.soundsoftware.ac.uk/projects/beaglert/embedded/structBeagleRTContext.html).
robert@269: 
robert@269: You can access any of these bits of information about current audio and sensor 
robert@269: settings and pointers to data buffers that are contained in the data structure 
robert@269: like this: `context->name_of_item`.
robert@269: 
robert@269: For example, `context->audioChannels` returns the number of audio channels. 
robert@269: `context->audioSampleRate` returns the audio sample rate. 
robert@269: `context->audioIn[n]` would give you the current input sample (assuming that 
robert@269: your input is mono - if it's not you will have to account for multiple channels).
robert@269: 
robert@269: Note that `audioIn`, `audioOut`, `analogIn`, `analogOut` are all arrays (buffers).
robert@269: 
robert@269: */
robert@269: 
robert@269: 
robert@269: 
robert@269: 
robert@269: #include <BeagleRT.h>
robert@269: #include <Utilities.h>
robert@269: #include <rtdk.h>
robert@269: #include <cmath>
robert@269: 
robert@269: // setup() is called once before the audio rendering starts.
robert@269: // Use it to perform any initialisation and allocation which is dependent
robert@269: // on the period size or sample rate.
robert@269: //
robert@269: // userData holds an opaque pointer to a data structure that was passed
robert@269: // in from the call to initAudio().
robert@269: //
robert@269: // Return true on success; returning false halts the program.
robert@269: 
robert@269: bool setup(BeagleRTContext *context, void *userData)
robert@269: {
robert@269: 
robert@269: 	return true;
robert@269: }
robert@269: 
robert@269: // render() is called regularly at the highest priority by the audio engine.
robert@269: // Input and output are given from the audio hardware and the other
robert@269: // ADCs and DACs (if available). If only audio is available, numMatrixFrames
robert@269: // will be 0.
robert@269: 
robert@269: void render(BeagleRTContext *context, void *userData)
robert@269: {
robert@269: 
robert@269: }
robert@269: 
robert@269: // cleanup() is called once at the end, after the audio has stopped.
robert@269: // Release any resources that were allocated in setup().
robert@269: 
robert@269: void cleanup(BeagleRTContext *context, void *userData)
robert@269: {
robert@269: 
robert@269: }