comparison examples/03-Analog/scope-analog/render.cpp @ 464:8fcfbfb32aa0 prerelease

Examples reorder with subdirectories. Added header to each project. Moved Doxygen to bottom of render.cpp.

+/*
+ ____  _____ _        _    
+| __ )| ____| |      / \   
+|  _ \|  _| | |     / _ \  
+| |_) | |___| |___ / ___ \ 
+|____/|_____|_____/_/   \_\
+
+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 <cmath>
+#include <Scope.h>
+
+Scope scope;
+
+float gInverseSampleRate;
+float gPhase;
+
+bool setup(BelaContext *context, void *userData)
+{
+
+    // setup the scope with 3 channels at the audio sample rate
+	scope.setup(3, context->audioSampleRate);
+	
+	gInverseSampleRate = 1.0 / context->audioSampleRate;
+	gPhase = 0.0;
+
+	return true;
+}
+
+void render(BelaContext *context, void *userData)
+{
+
+	for(unsigned int n = 0; n < context->audioFrames; n++) {
+	    
+	    // read analogIn channels 0 and 1
+	    float in1 = analogRead(context, n, 0);
+	    float in2 = analogRead(context, n, 1);
+	    
+	    // map in1 to amplitude and in2 to frequency
+	    float amplitude = in1 * 0.8f;
+	    float frequency = map(in2, 0, 1, 100, 1000);
+	    
+	    // generate a sine wave with the amplitude and frequency 
+	    float out = amplitude * sinf(gPhase);
+	    gPhase += 2.0 * M_PI * frequency * gInverseSampleRate;
+		if(gPhase > 2.0 * M_PI)
+			gPhase -= 2.0 * M_PI;
+	    
+	    // log the sine wave and sensor values on the scope
+	    scope.log(out, in1, in2);
+	    
+	    // pass the sine wave to the audio outputs
+	    for(unsigned int channel = 0; channel < context->audioChannels; channel++)
+			context->audioOut[n * context->audioChannels + channel] = out;
+
+	}
+}
+
+void cleanup(BelaContext *context, void *userData)
+{
+
+}
+
+/* ------------ Project Explantation ------------ */
+
+/**
+\example 03-scope-analog
+
+Connecting potentiometers
+-------------------------
+
+This example reads from analogue inputs 0 and 1 via `analogReadFrame()` and 
+generates a sine wave with amplitude and frequency determined by their values. 
+It's best to connect a 10K potentiometer to each of these analog inputs. Far 
+left and far right pins of the pot go to 3.3V and GND, the middle should be 
+connected to the analog in pins.
+
+The sine wave is then plotted on the oscilloscope. Click the Open Scope button to 
+view the results. As you turn the potentiometers you will see the amplitude and 
+frequency of the sine wave change.
+
+This project also shows as example of `map()` which allows you to re-scale a number 
+from one range to another. Note that `map()` does not constrain your variable 
+within the upper and lower limits. If you want to do this use the `constrain()`
+function.
+*/