comparison examples/11-Extras/userdata/render.cpp @ 543:8f8809c77dda prerelease

updated basics, digital, instruments, extras examples

+/*
+ ____  _____ _        _    
+| __ )| ____| |      / \   
+|  _ \|  _| | |     / _ \  
+| |_) | |___| |___ / ___ \ 
+|____/|_____|_____/_/   \_\
+
+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>
+
+float gFrequency = 440.0;
+float gPhase;
+float gInverseSampleRate;
+
+bool setup(BelaContext *context, void *userData)
+{
+	/*
+	 *  Retrieve the parameter passed in from the Bela_initAudio() call in main.cpp
+	 */
+	if(userData != 0)
+		gFrequency = *(float *)userData;
+
+	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++) {
+		float out = 0.8f * sinf(gPhase);
+		gPhase += 2.0 * M_PI * gFrequency * gInverseSampleRate;
+		if(gPhase > 2.0 * M_PI)
+			gPhase -= 2.0 * M_PI;
+
+		for(unsigned int channel = 0; channel < context->audioOutChannels; channel++) {
+			// Two equivalent ways to write this code
+
+			// The long way, using the buffers directly:
+			// context->audioOut[n * context->audioOutChannels + channel] = out;
+
+			// Or using the macros:
+			audioWrite(context, n, channel, out);
+		}
+	}
+}
+
+void cleanup(BelaContext *context, void *userData)
+{
+
+}
+
+
+/**
+\example userdata/render.cpp
+
+Passing parameters using the `*userData` argument
+-------------------------------------------------
+
+This sketch demonstrates how to pass command line arguments using the `*userData` argument inside the `setup()` function.
+
+In main.cpp we first parse a command line argument `-f` and allocate its value to the variable `frequency`.
+We then pass the address of this variable when we call `Bela_initAudio()`. The variable can now be accessed from the
+`setup()` and `render()` functions inside render.cpp.
+
+*/