comparison projects/basic_analog_output/render.cpp @ 0:8a575ba3ab52

Initial commit.

+/*
+ * render.cpp
+ *
+ *  Created on: Oct 24, 2014
+ *      Author: parallels
+ */
+
+
+#include "../../include/render.h"
+#include "../../include/Utilities.h"
+#include <rtdk.h>
+#include <cmath>
+
+// Set range for analog outputs designed for driving LEDs
+const float kMinimumAmplitude = (1.5 / 5.0) * MATRIX_MAX;
+const float kAmplitudeRange = MATRIX_MAX - kMinimumAmplitude;
+
+float gFrequency;
+float gPhase;
+float gInverseSampleRate;
+
+// initialise_render() 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 initialise_render(int numChannels, int numMatrixFramesPerPeriod,
+					   int numAudioFramesPerPeriod, float matrixSampleRate,
+					   float audioSampleRate, void *userData)
+{
+	// Retrieve a parameter passed in from the initAudio() call
+	gFrequency = *(float *)userData;
+
+	if(numMatrixFramesPerPeriod*2 != numAudioFramesPerPeriod) {
+		rt_printf("Error: this example needs the matrix enabled, running at half audio rate\n");
+		return false;
+	}
+
+	gInverseSampleRate = 1.0 / 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(int numMatrixFrames, int numAudioFrames, float *audioIn, float *audioOut,
+			uint16_t *matrixIn, uint16_t *matrixOut)
+{
+	for(int n = 0; n < numMatrixFrames; n++) {
+		// Set LED to different phase for each matrix channel
+		float relativePhase = 0.0;
+		for(int channel = 0; channel < 8; channel++) {
+			float out = kMinimumAmplitude + kAmplitudeRange * 0.5f * (1.0f + sinf(gPhase + relativePhase));
+			if(out > MATRIX_MAX)
+				out = MATRIX_MAX;
+
+			matrixOut[n * 8 + channel] = (uint16_t)out;
+
+			// Advance by pi/4 (1/8 of a full rotation) for each channel
+			relativePhase += M_PI * 0.25;
+		}
+
+		gPhase += 2.0 * M_PI * gFrequency * gInverseSampleRate;
+		if(gPhase > 2.0 * M_PI)
+			gPhase -= 2.0 * M_PI;
+	}
+}
+
+// cleanup_render() is called once at the end, after the audio has stopped.
+// Release any resources that were allocated in initialise_render().
+
+void cleanup_render()
+{
+
+}