Mercurial > hg > beaglert
diff examples/01-Basics/minimal/render.cpp @ 464:8fcfbfb32aa0 prerelease
Examples reorder with subdirectories. Added header to each project. Moved Doxygen to bottom of render.cpp.
author | Robert Jack <robert.h.jack@gmail.com> |
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date | Mon, 20 Jun 2016 16:20:38 +0100 |
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children | b935f890e512 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/examples/01-Basics/minimal/render.cpp Mon Jun 20 16:20:38 2016 +0100 @@ -0,0 +1,120 @@ +/* + ____ _____ _ _ +| __ )| ____| | / \ +| _ \| _| | | / _ \ +| |_) | |___| |___ / ___ \ +|____/|_____|_____/_/ \_\ + +The platform for ultra-low latency audio and sensor processing + +http://bela.io + +A project of the Augmented Instruments Laboratory within the +Centre for Digital Music at Queen Mary University of London. +http://www.eecs.qmul.ac.uk/~andrewm + +(c) 2016 Augmented Instruments Laboratory: Andrew McPherson, + Astrid Bin, Liam Donovan, Christian Heinrichs, Robert Jack, + Giulio Moro, Laurel Pardue, Victor Zappi. All rights reserved. + +The Bela software is distributed under the GNU Lesser General Public License +(LGPL 3.0), available here: https://www.gnu.org/licenses/lgpl-3.0.txt +*/ + +#include <Bela.h> + + +// 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(BelaContext *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(BelaContext *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(BelaContext *context, void *userData) +{ + +} + +/* ------------ Project Explantation ------------ */ + +/** + +\example 01-minimal + +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). + +*/ \ No newline at end of file