diff examples/basic_analog_input/render.cpp @ 300:dbeed520b014 prerelease

Renamed projects to examples

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/basic_analog_input/render.cpp	Fri May 27 13:58:20 2016 +0100
@@ -0,0 +1,85 @@
+/*
+ * render.cpp
+ *
+ *  Created on: Oct 24, 2014
+ *      Author: parallels
+ */
+
+
+#include <BeagleRT.h>
+#include <Utilities.h>
+#include <rtdk.h>
+#include <cmath>
+
+float gPhase;
+float gInverseSampleRate;
+int gAudioFramesPerAnalogFrame;
+
+// These settings are carried over from main.cpp
+// Setting global variables is an alternative approach
+// to passing a structure to userData in setup()
+
+extern int gSensorInputFrequency;
+extern int gSensorInputAmplitude;
+
+// setup() is called once before the audio rendering starts.
+// Use it to perform any initialisation and allocation which is dependent
+// on the period size or sample rate.
+//
+// userData holds an opaque pointer to a data structure that was passed
+// in from the call to initAudio().
+//
+// Return true on success; returning false halts the program.
+
+bool setup(BeagleRTContext *context, void *userData)
+{
+	if(context->analogFrames == 0 || context->analogFrames > context->audioFrames) {
+		rt_printf("Error: this example needs analog enabled, with 4 or 8 channels\n");
+		return false;
+	}
+
+	gAudioFramesPerAnalogFrame = context->audioFrames / context->analogFrames;
+	gInverseSampleRate = 1.0 / context->audioSampleRate;
+	gPhase = 0.0;
+
+	return true;
+}
+
+// render() is called regularly at the highest priority by the audio engine.
+// Input and output are given from the audio hardware and the other
+// ADCs and DACs (if available). If only audio is available, numMatrixFrames
+// will be 0.
+
+void render(BeagleRTContext *context, void *userData)
+{
+	float frequency = 440.0;
+	float amplitude = 0.8;
+
+	// There are twice as many audio frames as matrix frames since audio sample rate
+	// is twice as high
+
+	for(unsigned int n = 0; n < context->audioFrames; n++) {
+		if(!(n % gAudioFramesPerAnalogFrame)) {
+			// Even audio samples: update frequency and amplitude from the matrix
+			frequency = map(analogReadFrame(context, n/gAudioFramesPerAnalogFrame, gSensorInputFrequency), 0, 1, 100, 1000);
+			amplitude = analogReadFrame(context, n/gAudioFramesPerAnalogFrame, gSensorInputAmplitude);
+		}
+
+		float out = amplitude * sinf(gPhase);
+
+		for(unsigned int channel = 0; channel < context->audioChannels; channel++)
+			context->audioOut[n * context->audioChannels + channel] = out;
+
+		gPhase += 2.0 * M_PI * frequency * gInverseSampleRate;
+		if(gPhase > 2.0 * M_PI)
+			gPhase -= 2.0 * M_PI;
+	}
+}
+
+// cleanup() is called once at the end, after the audio has stopped.
+// Release any resources that were allocated in setup().
+
+void cleanup(BeagleRTContext *context, void *userData)
+{
+
+}