Mercurial > hg > beaglert
diff examples/01-Basics/passthrough/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/passthrough/render.cpp Mon Jun 20 16:20:38 2016 +0100 @@ -0,0 +1,119 @@ +/* + ____ _____ _ _ +| __ )| ____| | / \ +| _ \| _| | | / _ \ +| |_) | |___| |___ / ___ \ +|____/|_____|_____/_/ \_\ + +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> +#include <rtdk.h> + +bool setup(BelaContext *context, void *userData) +{ + // Nothing to do here... + return true; +} + +void render(BelaContext *context, void *userData) +{ + // Simplest possible case: pass inputs through to outputs + for(unsigned int n = 0; n < context->audioFrames; n++) { + for(unsigned int ch = 0; ch < context->audioChannels; ch++){ + // Two equivalent ways to write this code + + // The long way, using the buffers directly: + // context->audioOut[n * context->audioChannels + ch] = + // context->audioIn[n * context->audioChannels + ch]; + + // Or using the macros: + audioWrite(context, n, ch, audioRead(context, n, ch)); + } + } + + // Same with analog channelss + for(unsigned int n = 0; n < context->analogFrames; n++) { + for(unsigned int ch = 0; ch < context->analogChannels; ch++) { + // Two equivalent ways to write this code + + // The long way, using the buffers directly: + // context->analogOut[n * context->analogChannels + ch] = context->analogIn[n * context->analogChannels + ch]; + + // Or using the macros: + analogWrite(context, n, ch, analogRead(context, n, ch)); + } + } +} + +void cleanup(BelaContext *context, void *userData) +{ + +} + +/* ------------ Project Explantation ------------ */ + +/** +\example 01-passthrough + +Audio and analog passthrough: input to output +----------------------------------------- + +This sketch demonstrates how to read from and write to the audio and analog input and output buffers. + +In `render()` you'll see a nested for loop structure. You'll see this in all Bela projects. +The first for loop cycles through `audioFrames`, the second through +`audioChannels` (in this case left 0 and right 1). + +You can access any information about current audio and sensor settings you can do the following: +`context->name_of_item`. For example `context->audioChannels` returns current number of channels, +`context->audioFrames` returns the current number of audio frames, +`context->audioSampleRate` returns the audio sample rate. + +You can look at all the information you can access in ::BeagleRTContext. + +Reading and writing from the audio buffers +------------------------------------------ + +The simplest way to read samples from the audio input buffer is with +`audioRead()` which we pass three arguments: context, current audio +frame and current channel. In this example we have +`audioRead(context, n, ch)` where both `n` and `ch` are provided by +the nested for loop structure. + +We can write samples to the audio output buffer in a similar way using +`audioWrite()`. This has a fourth argument which is the value of the output. +For example `audioWrite(context, n, ch, value_to_output)`. + +Reading and writing from the analog buffers +------------------------------------------- + +The same is true for `analogRead()` and `analogWrite()`. + +Note that for the analog channels we write to and read from the buffers in a separate set +of nested for loops. This is because the they are sampled at half audio rate by default. +The first of these for loops cycles through `analogFrames`, the second through +`analogChannels`. + +By setting `audioWriteFrame(context, n, ch, audioReadFrame(context, n, ch))` and +`analogWrite(context, n, ch, analogReadFrame(context, n, ch))` we have a simple +passthrough of audio input to output and analog input to output. + + +It is also possible to address the buffers directly, for example: +`context->audioOut[n * context->audioChannels + ch]`. +*/