Austin Suszek / Mbed 2 deprecated MIDISynthesizer

A MIDI piano synthesizer that implements the Karplus Strong physical modeling algorithm.

Dependencies:   mbed USBDevice PinDetect

Audio/KarplusStrong.h@22:b800e1766647, 2016-04-25 (annotated)

Committer:
asuszek
Date:
Mon Apr 25 23:58:15 2016 +0000
Revision:
22:b800e1766647
Parent:
19:894c31ee9ad4 
Fixed LED bug

Who changed what in which revision?

UserRevisionLine numberNew contents of line
asuszek 13:bb0ec927e458 1
asuszek 13:bb0ec927e458 2 /**
asuszek 13:bb0ec927e458 3 * The processor used for teh implementation of Karplus strong.
asuszek 13:bb0ec927e458 4 *
asuszek 13:bb0ec927e458 5 * @author Austin Suszek
asuszek 13:bb0ec927e458 6 */
asuszek 13:bb0ec927e458 7
asuszek 13:bb0ec927e458 8 #ifndef AS_KARPLUS_STRONG_H
asuszek 13:bb0ec927e458 9 #define AS_KARPLUS_STRONG_H
asuszek 13:bb0ec927e458 10
asuszek 13:bb0ec927e458 11 #include <math.h>
asuszek 13:bb0ec927e458 12 #include <stdlib.h>
asuszek 13:bb0ec927e458 13 #include <time.h>
asuszek 13:bb0ec927e458 14
asuszek 13:bb0ec927e458 15 #include "../Constants.h"
asuszek 13:bb0ec927e458 16
asuszek 13:bb0ec927e458 17 class KarplusStrong {
asuszek 13:bb0ec927e458 18 public:
asuszek 13:bb0ec927e458 19
asuszek 13:bb0ec927e458 20 /**
asuszek 13:bb0ec927e458 21 * Constructor
asuszek 13:bb0ec927e458 22 */
asuszek 13:bb0ec927e458 23 KarplusStrong();
asuszek 13:bb0ec927e458 24
asuszek 13:bb0ec927e458 25 /**
asuszek 13:bb0ec927e458 26 * Signal the start of a new note.
asuszek 13:bb0ec927e458 27 *
asuszek 13:bb0ec927e458 28 * @param key The integer representation of the note
asuszek 13:bb0ec927e458 29 * @param velocity The float representation of the velocity (NOT int!)
asuszek 13:bb0ec927e458 30 */
asuszek 13:bb0ec927e458 31 void midiNoteOn(int key, float velocity);
asuszek 13:bb0ec927e458 32
asuszek 13:bb0ec927e458 33 /**
asuszek 13:bb0ec927e458 34 * Create the initial buffer sample for the specific index.
asuszek 13:bb0ec927e458 35 *
asuszek 13:bb0ec927e458 36 * @param bufferIndex The index to process
asuszek 13:bb0ec927e458 37 * @return The new sample to save in the buffer
asuszek 13:bb0ec927e458 38 */
asuszek 13:bb0ec927e458 39 float fillBuffer(const int bufferIndex);
asuszek 13:bb0ec927e458 40
asuszek 13:bb0ec927e458 41 /**
asuszek 13:bb0ec927e458 42 * Process the existing buffer for the specific index.
asuszek 13:bb0ec927e458 43 *
asuszek 13:bb0ec927e458 44 * @param inputSample The sample to process from the buffer
asuszek 13:bb0ec927e458 45 * @return The modified sample to save in the buffer
asuszek 13:bb0ec927e458 46 */
asuszek 13:bb0ec927e458 47 float processBuffer(const float inputSample);
asuszek 13:bb0ec927e458 48
asuszek 13:bb0ec927e458 49 private:
asuszek 13:bb0ec927e458 50
asuszek 13:bb0ec927e458 51 static void initializeNoiseSeed();
asuszek 13:bb0ec927e458 52 static float getRand() {
asuszek 13:bb0ec927e458 53 return float(rand()) / float(RAND_MAX);
asuszek 13:bb0ec927e458 54 };
asuszek 15:aa5a4c350251 55 static float getRandSample() {
asuszek 15:aa5a4c350251 56 return 1.0 - 2.0 * getRand();
asuszek 15:aa5a4c350251 57 };
asuszek 13:bb0ec927e458 58
asuszek 13:bb0ec927e458 59 float lastOutput;
asuszek 13:bb0ec927e458 60 float filterCoefficient;
asuszek 13:bb0ec927e458 61 float nextFilterCoefficient;
asuszek 13:bb0ec927e458 62
asuszek 16:b25ca34a705f 63 static const float pluckDampingVariationMin;
asuszek 16:b25ca34a705f 64 static const float pluckDampingVariationDifference;
asuszek 16:b25ca34a705f 65 float pluckDampingCoefficient;
asuszek 16:b25ca34a705f 66
asuszek 13:bb0ec927e458 67 float lowpassFilter(const float output, const float input, const float smoothingFactor);
asuszek 13:bb0ec927e458 68
asuszek 13:bb0ec927e458 69 };
asuszek 13:bb0ec927e458 70
asuszek 13:bb0ec927e458 71 #endif