comparison examples/04-Audio/FFT-audio-in/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 <rtdk.h>
+#include <ne10/NE10.h>					// neon library
+#include <cmath>
+
+int gFFTSize;
+
+int gReadPointer = 0;
+int gWritePointer = 0;
+
+// FFT vars
+static ne10_fft_cpx_float32_t* timeDomainIn;
+static ne10_fft_cpx_float32_t* timeDomainOut;
+static ne10_fft_cpx_float32_t* frequencyDomain;
+static ne10_fft_cfg_float32_t cfg;
+
+bool setup(BelaContext *context, void *userData)
+{
+	// Retrieve a parameter passed in from the initAudio() call
+	gFFTSize = *(int *)userData;
+
+	timeDomainIn = (ne10_fft_cpx_float32_t*) NE10_MALLOC (gFFTSize * sizeof (ne10_fft_cpx_float32_t));
+	timeDomainOut = (ne10_fft_cpx_float32_t*) NE10_MALLOC (gFFTSize * sizeof (ne10_fft_cpx_float32_t));
+	frequencyDomain = (ne10_fft_cpx_float32_t*) NE10_MALLOC (gFFTSize * sizeof (ne10_fft_cpx_float32_t));
+	cfg = ne10_fft_alloc_c2c_float32_neon (gFFTSize);
+
+	memset(timeDomainOut, 0, gFFTSize * sizeof (ne10_fft_cpx_float32_t));
+
+	return true;
+}
+
+void render(BelaContext *context, void *userData)
+{
+	for(unsigned int n = 0; n < context->audioFrames; n++) {
+		timeDomainIn[gReadPointer].r = (ne10_float32_t) ((context->audioIn[n*context->audioChannels] +
+															context->audioIn[n*context->audioChannels+1]) * 0.5);
+		timeDomainIn[gReadPointer].i = 0;
+
+		if(++gReadPointer >= gFFTSize)
+		{
+			//FFT
+			ne10_fft_c2c_1d_float32_neon (frequencyDomain, timeDomainIn, cfg, 0);
+
+			//Do frequency domain stuff
+
+			//IFFT
+			ne10_fft_c2c_1d_float32_neon (timeDomainOut, frequencyDomain, cfg, 1);
+
+			gReadPointer = 0;
+			gWritePointer = 0;
+		}
+
+		for(unsigned int channel = 0; channel < context->audioChannels; channel++)
+			context->audioOut[n * context->audioChannels + channel] = (float) timeDomainOut[gWritePointer].r;
+		gWritePointer++;
+	}
+}
+
+void cleanup(BelaContext *context, void *userData)
+{
+	NE10_FREE(timeDomainIn);
+	NE10_FREE(timeDomainOut);
+	NE10_FREE(frequencyDomain);
+	NE10_FREE(cfg);
+}
+
+/* ------------ Project Explantation ------------ */
+
+/**
+\example 04-FFT-audio-in
+
+Fast Fourier Transform
+----------------------
+
+This sketch performs an FFT (Fast Fourier Transform) on incoming audio. It uses 
+the NE10 library, included at the top of the file.
+
+Read the documentation on the NE10 library [here](http://projectne10.github.io/Ne10/doc/annotated.html).
+
+The variables `timeDomainIn`, `timeDomainOut` and `frequencyDomain` are 
+variables of the struct `ne10_fft_cpx_float32_t` [http://projectne10.github.io/Ne10/doc/structne10__fft__cpx__float32__t.html](http://projectne10.github.io/Ne10/doc/structne10__fft__cpx__float32__t.html). 
+These are declared at the top of the file, and memory is allocated 
+for them in `setup()`.
+
+In `render()` a `for` loop performs the FFT which is performed on each sample, 
+and the resulting output is placed on each channel.
+*/