comparison 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>
date Mon, 20 Jun 2016 16:20:38 +0100
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children b935f890e512
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463:c47709e8b5c9 464:8fcfbfb32aa0
1 /*
2 ____ _____ _ _
3 | __ )| ____| | / \
4 | _ \| _| | | / _ \
5 | |_) | |___| |___ / ___ \
6 |____/|_____|_____/_/ \_\
7
8 The platform for ultra-low latency audio and sensor processing
9
10 http://bela.io
11
12 A project of the Augmented Instruments Laboratory within the
13 Centre for Digital Music at Queen Mary University of London.
14 http://www.eecs.qmul.ac.uk/~andrewm
15
16 (c) 2016 Augmented Instruments Laboratory: Andrew McPherson,
17 Astrid Bin, Liam Donovan, Christian Heinrichs, Robert Jack,
18 Giulio Moro, Laurel Pardue, Victor Zappi. All rights reserved.
19
20 The Bela software is distributed under the GNU Lesser General Public License
21 (LGPL 3.0), available here: https://www.gnu.org/licenses/lgpl-3.0.txt
22 */
23
24 #include <Bela.h>
25
26
27 // setup() is called once before the audio rendering starts.
28 // Use it to perform any initialisation and allocation which is dependent
29 // on the period size or sample rate.
30 //
31 // userData holds an opaque pointer to a data structure that was passed
32 // in from the call to initAudio().
33 //
34 // Return true on success; returning false halts the program.
35 bool setup(BelaContext *context, void *userData)
36 {
37 return true;
38 }
39
40 // render() is called regularly at the highest priority by the audio engine.
41 // Input and output are given from the audio hardware and the other
42 // ADCs and DACs (if available). If only audio is available, numMatrixFrames
43 // will be 0.
44 void render(BelaContext *context, void *userData)
45 {
46
47 }
48
49 // cleanup() is called once at the end, after the audio has stopped.
50 // Release any resources that were allocated in setup().
51 void cleanup(BelaContext *context, void *userData)
52 {
53
54 }
55
56 /* ------------ Project Explantation ------------ */
57
58 /**
59
60 \example 01-minimal
61
62 The bare bones
63 ----------------------
64
65 The structure of a render.cpp file
66 ----------------------------------
67 A render.cpp file has three functions: `setup()`, `render()` and `cleanup()`.
68
69 `setup()` is an initialisation function which runs before audio rendering begins.
70 It is called once when the project starts. Use it to prepare any memory or
71 resources that will be needed in `render()`.
72
73 `render()` is a function that is regularly called, over and over continuously, at
74 the highest priority by the audio engine. It is used to process audio and
75 sensor data. This function is called regularly by the system every time there
76 is a new block of audio and/or sensor data to process.
77
78 `cleanup()` is a function that is called when the program stops, to finish up any
79 processes that might still be running.
80
81 Here we will briefly explain each function and the structure of the render.cpp
82
83 Before any of the functions
84 ---------------------------
85 At the top of the file, include any libraries you might need.
86
87 Additionally, declare any global variables. In these tutorial sketches, all
88 global variables are preceded by a `g` so we always know which variables are
89 global - `gSampleData`, for example. It's not mandatory but is a really good way
90 of keeping track of what's global and what's not.
91
92 Sometimes it's necessary to access a variable from another file, such as
93 main.cpp. In this case, precede this variable with the keyword `extern`.
94
95 Function arguments
96 ------------------
97 `setup()`, `render()` and `cleanup()` each take the same arguments. These are:
98
99 `0ext *context`
100 `void *userData`
101
102 These arguments are pointers to data structures. The main one that's used is
103 `context`, which is a pointer to a data structure containing lots of information
104 you need.
105
106 Take a look at what's in the data structure [here]
107 (https://code.soundsoftware.ac.uk/projects/beaglert/embedded/structBeagleRTContext.html).
108
109 You can access any of these bits of information about current audio and sensor
110 settings and pointers to data buffers that are contained in the data structure
111 like this: `context->name_of_item`.
112
113 For example, `context->audioChannels` returns the number of audio channels.
114 `context->audioSampleRate` returns the audio sample rate.
115 `context->audioIn[n]` would give you the current input sample (assuming that
116 your input is mono - if it's not you will have to account for multiple channels).
117
118 Note that `audioIn`, `audioOut`, `analogIn`, `analogOut` are all arrays (buffers).
119
120 */