robert@464: /*
robert@464:  ____  _____ _        _    
robert@464: | __ )| ____| |      / \   
robert@464: |  _ \|  _| | |     / _ \  
robert@464: | |_) | |___| |___ / ___ \ 
robert@464: |____/|_____|_____/_/   \_\
robert@464: 
robert@464: The platform for ultra-low latency audio and sensor processing
robert@464: 
robert@464: http://bela.io
robert@464: 
robert@464: A project of the Augmented Instruments Laboratory within the
robert@464: Centre for Digital Music at Queen Mary University of London.
robert@464: http://www.eecs.qmul.ac.uk/~andrewm
robert@464: 
robert@464: (c) 2016 Augmented Instruments Laboratory: Andrew McPherson,
robert@464: 	Astrid Bin, Liam Donovan, Christian Heinrichs, Robert Jack,
robert@464: 	Giulio Moro, Laurel Pardue, Victor Zappi. All rights reserved.
robert@464: 
robert@464: The Bela software is distributed under the GNU Lesser General Public License
robert@464: (LGPL 3.0), available here: https://www.gnu.org/licenses/lgpl-3.0.txt
robert@464: */
robert@464: 
robert@464: #include <Bela.h>
robert@464: #include <cmath>
robert@464: 
robert@464: float gFrequency = 440.0;
robert@464: float gPhase;
robert@464: float gInverseSampleRate;
robert@464: 
robert@464: bool setup(BelaContext *context, void *userData)
robert@464: {
robert@464: 	gInverseSampleRate = 1.0 / context->audioSampleRate;
chris@546: 	gPhase = 0.0;
robert@464: 
robert@464: 	return true;
robert@464: }
robert@464: 
robert@464: void render(BelaContext *context, void *userData)
robert@464: {
robert@464: 	for(unsigned int n = 0; n < context->audioFrames; n++) {
robert@464: 		float out = 0.8f * sinf(gPhase);
robert@464: 		gPhase += 2.0 * M_PI * gFrequency * gInverseSampleRate;
robert@464: 		if(gPhase > 2.0 * M_PI)
robert@464: 			gPhase -= 2.0 * M_PI;
robert@464: 
chris@543: 		for(unsigned int channel = 0; channel < context->audioOutChannels; channel++) {
robert@464: 			// Two equivalent ways to write this code
robert@464: 
robert@464: 			// The long way, using the buffers directly:
chris@543: 			// context->audioOut[n * context->audioOutChannels + channel] = out;
robert@464: 
robert@464: 			// Or using the macros:
robert@464: 			audioWrite(context, n, channel, out);
robert@464: 		}
robert@464: 	}
robert@464: }
robert@464: 
robert@464: void cleanup(BelaContext *context, void *userData)
robert@464: {
robert@464: 
robert@464: }
robert@464: 
robert@464: 
robert@464: /**
robert@500: \example sinetone/render.cpp
robert@464: 
robert@464: Producing your first bleep!
robert@464: ---------------------------
robert@464: 
robert@464: This sketch is the hello world of embedded interactive audio. Better known as bleep, it 
robert@464: produces a sine tone.
robert@464: 
robert@464: The frequency of the sine tone is determined by a global variable, `gFrequency` 
robert@464: (line 12). The sine tone is produced by incrementing the phase of a sin function 
robert@464: on every audio frame.
robert@464: 
robert@464: In render() you'll see a nested for loop structure. You'll see this in all Bela projects. 
robert@464: The first for loop cycles through 'audioFrames', the second through 'audioChannels' (in this case left 0 and right 1). 
robert@464: It is good to familiarise yourself with this structure as it's fundamental to producing sound with the system.
robert@464: */