MIDITapTempo.csd Written by Iain McCurdy 2008. Updated 2011. -iadc -odac -Ma -dm0 sr = 44100 ksmps = 8 nchnls = 1 0dbfs = 1 ;FLTK INTERFACE CODE;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; FLcolor 255, 255, 255, 50, 0, 0 ; LABEL | WIDTH | HEIGHT | X | Y FLpanel "MIDI Tap Tempo", 300, 125, 0, 0 ;KOUT | HANDLE FLTEXT "LABEL" | MIN | MAX | STEP | TYPE | WIDTH | HEIGHT | X | Y gkBeatDur, gihBeatDur FLtext "Beat Duration", 0, 20, 0, 1, 100, 25, 25, 25 gkTempo, gihTempo FLtext "Tempo", 0, 10000, 0.01, 1, 100, 25, 175, 25 ;BUTTONS ON | OFF | TYPE | WIDTH | HEIGHT | X | Y | OPCODE | I | STARTTIM | IDUR gkMetronome,ihMetronome FLbutton "Metronome", 1, 0, 22, 100, 25, 25, 75, 0, 3, 0, -1 gkDelay,ihDelay FLbutton "Delay", 1, 0, 22, 100, 25, 175, 75, 0, 5, 0, -1 FLsetColor2 255, 255, 50, ihMetronome ;SET SECONDARY COLOUR TO YELLOW FLsetColor2 255, 255, 50, ihDelay ;SET SECONDARY COLOUR TO YELLOW FLsetVal_i 60,gihTempo FLsetVal_i 1,gihBeatDur FLpanel_end ;INSTRUCTIONS AND INFO PANEL WIDTH | HEIGHT | X | Y FLpanel "info", 500, 220, 312, 0 ;TEXT BOXES TYPE | FONT | SIZE | WIDTH | HEIGHT | X | Y ih FLbox " MIDI Tap Tempo ", 1, 5, 14, 490, 20, 5, 0 ih FLbox "-------------------------------------------------------------", 1, 5, 14, 490, 20, 5, 20 ih FLbox "This example demonstrates a method for defining a tempo by ", 1, 5, 14, 490, 20, 5, 40 ih FLbox "tapping notes on a MIDI keyboard. The time gap between notes ", 1, 5, 14, 490, 20, 5, 60 ih FLbox "is averaged across a number of taps, from this a tempo value ", 1, 5, 14, 490, 20, 5, 80 ih FLbox "is derived and this result can be used to define the tempo of", 1, 5, 14, 490, 20, 5, 100 ih FLbox "a metronome or the delay time of a simple delay effect that ", 1, 5, 14, 490, 20, 5, 120 ih FLbox "is applied to the live audio input of the computer. ", 1, 5, 14, 490, 20, 5, 140 ih FLbox "The average of the previous two time gap readings is taken, ", 1, 5, 14, 490, 20, 5, 160 ih FLbox "A minimum of four note taps will normally be required to ", 1, 5, 14, 490, 20, 5, 180 ih FLbox "derive an accurate tempo. ", 1, 5, 14, 490, 20, 5, 200 FLpanel_end FLrun gisine ftgen 0,0,4096,10,1 ;A SINE WAVE gkDlyTim init 1 ;INITIALISE DELAY TIME VARIABLE USED IN THE DELAY EFFECT IN INSTR 4 gkTimer init 1 ;TIMER THAT MEASURES THE TIME GAP BETWEEN ADJACENT NOTES giTimeGap init 1 ;MOST RECENT TIME GAP gkBeatDur init 1 ;AVERAGE OF ALL TIME GAPS STORED IN TABLE gkTempo init 60 ;CURRENT TEMPO giTimes ftgen 0,0,-2,-2,1,1 ;TABLE TO STORE TIME GAPS giTabLoc init 0 ;TABLE LOCATION COUNTER gkNoteOnFlag init 0 ;TRIGGER IMPULSE WHENEVER A MIDI NOTE IS PLAYED (USED IN METRONOME INSTRUMENT) instr timer ;RUNS TIMER gkTimer timeinsts ;TIMER READS THE TIME SINCE THIS NOTE BEGAN endin instr 1 ;MIDI TRIGGERED INSTRUMENT - RECEIVES 'TAPS' ;SENSE TEMPO iTimeGap init i(gkTimer) ;READ TIME GAP BETWEEN PREVIOUS NOTE AND THIS ONE iTimeGap = (iTimeGap>2?i(gkBeatDur):iTimeGap);DON'T ALLOW EXCESSIVELY LONG TIME GAPS - I.E. AFTER A LONG WAIT WHICH IS PROBABLY NOT INTENDED AS AN INDICATION OF TEMPO - INSTEAD REPLACE READING WITH THE CURRENT TEMPO tablew iTimeGap,giTabLoc,giTimes ;WRITE TIME GAP READING TO FUNCTION TABLE iNumVals = ftlen(giTimes) ;DEDUCE NUMBER OF TIMER READING LOCATIONS IN THE TABLE giTabLoc wrap giTabLoc+1,0,iNumVals ;INCREMENT THE TABLE LOCATION COUNTER. WRAP AROUN BACK TO ZERO IF REQUIRED iSumVals init 0 ;INITIALISE AND CLEAR SUM OF ALL TIME GAP READINGS STORED IN giTimes TABLE iLoopCount init 0 ;INITIALISE LOOP COUNTER LOOP_BEGIN: ;LABEL. LOOP BEGINS HERE ival table iLoopCount,giTimes ;READ TIME GAP READING FROM TABLE iSumVals = iSumVals+ival ;ADD TIME GAP READING FROM TABLE TO THE ACCUMULATING VARIABLE iSumVals loop_lt iLoopCount, 1, iNumVals, LOOP_BEGIN ;LOOP BACK TO THE BEGINNING OF THE LOOP IF THERE ARE STILL MORE TIME GAP READINGS TO BE READ gkBeatDur init iSumVals/iNumVals ;FIND THE AVERAGE OF THE TABLE FLsetVal_i i(gkBeatDur),gihBeatDur ;WRITE THE AVERAGE TO FLTK NUMBER BOX gkTempo init 60/i(gkBeatDur) ;DEDUCE TEMPO FLsetVal_i i(gkTempo),gihTempo ;WRITE TEMPO VALUE TO FLTK NUMBER BO event_i "i","timer",0,-1 ;START TIMER TO READ TIME GAP UNTIL THE NEXT NOTE endin instr 3 ;METRONOME if gkMetronome=0 then ;IF METRONOME SWITCH IS OFF... turnoff ;...TURN THIS INSTRUMENT OFF endif ;END OF CONDITIONAL BRANCH if gkNoteOnFlag=1 then ;IF A MIDI NOTE HAS JUST BEEN STRUCK... reinit RESTART_METRO ;REINITIALISE THE METRONOME IN ORDER TO SYNC UP WITH MIDI KEY TAPS endif ;END OF CONDITIONAL BRANCH RESTART_METRO: ;A LABEL. REINTILISATION OF THE METRONOME BEGINS HERE. kmetro metro gkTempo/60 ;CREATE A TRAIN OF METRONOME TRIGGER ACCORDING TO CURRENT TEMPO rireturn ;RETURN FROM REINITIALISATION PASS if kmetro=1 then ;IF A METRONOME BEAT HAS BEEN RECEIVED reinit RESTART_CLICK ;RESTART THE METRONOME CLICK ENVELOPES endif ;END OF CONDITIONAL BRANCH RESTART_CLICK: ;A LABEL. REINTIALISATION OF THE METRONOME ENVELOPES (AMPLITUDE AND PITCH) BEGINS HERE. aenv linseg 0,0.001,1,0.005-0.001,0 ;PERCUSSIVE ENVELOPE afreq expseg 4000,0.005,200,1,200 ;PITCH OF TONE (VERY FAST GLISS) asig oscili 0.5*aenv,afreq,gisine ;CREATE AUDIO FOR METRONOME 'CLICK' rireturn ;RETURN FROM REINITIALISATION PASS out asig ;SEND AUDIO TO OUPUT gkNoteOnFlag = 0 ;CLEAR NOTE ON FLAG endin instr 5 ;DELAY if gkDelay=0 then turnoff endif ain inch 1 ;READ AUDIO FROM FIRST AUDIO INPUT CHANNEL kBeatDur limit gkBeatDur,0.001,8 ;LIMIT BEAT-DURATION VARIABLE TO BE WITHIN SENSIBLE LIMITS (NEEDED TO PROTECT AGAINST DELAY TIMES EXCEEDING BUFFER) aBeatDur interp kBeatDur ;CREATE A-RATE VERSION OF BEAT DURATION VARIABLE abuf delayr 8 ;DECLARE DELAY BUFFER aTap deltap3 aBeatDur ;READ AUDIO FROM A DELAY TAP WITHIN THE BUFFER delayw ain+(aTap*0.7) ;WRITE AUDIO INTO THE BUFFER (ADD A LITTLE BIT OF FEEDBACK FROM THE DELAY TAP ALSO) out ain+aTap ;SEND AUDIO TO OUTPUT (MIX OF DRY AND DELAYED AUDIO) endin f 0 3600