Using sound in processing?

So I'll admit I am a complete beginner when it comes to processing and the other day I was browsing some of the works on openprocessing.com and I came across an amazing program by Anton Pugh called Sound Waterfall (here is the link: http://openprocessing.org/sketch/46460) So I was wondering if it would be possible to somehow record myself playing my guitar and use that sound file in this program and have the program respond to the sound of my guitar instead of the song that playing.

Here's the code that I'm talking about

1. /* Created by Anton Pugh */

   /* Music Visualizer that samples the short-time fft of a song and */

   /* plots the sampled points (|fft| => brightness of point).       */

   // Note: If your machine has OpenGL capabilities, uncomment the

   // following line and change 'P3D' to 'OPENGL' on line 34

   //import processing.opengl.*;

   import ddf.minim.analysis.*;

   import ddf.minim.*;

   //import fullscreen.*;

   /* MAX_SPOTS is the maximum number of points the sketch can plot  */

   /* NUM_ITERATIONS determines how often fft is sampled into points */

   /*   - Higher number => less often

   /*   - 1 == as often as possible

   /* SPEED determines how fast points rotate                        */

   int MAX_SPOTS = 1000000;

   int NUM_ITERATIONS = 1;

   float SPEED = 4;

   // Declare a new Minim object which will allow us to play and

   // analyze music. If you want to use the computer sound card

   // output, leave code as is, otherwise comment out the AudioInput

   // line and uncomment the AudioPlayer line. Additionally, you

   // will need to change how the sketch gets data, so look in

   // the setup loop for song = minim.loadFile

   Minim minim;

   //AudioInput song;

   AudioPlayer song;

   FFT fft;

   //SoftFullScreen fs;

   Spot[] spots = new Spot[MAX_SPOTS];

   int numSpots, index, colorSwitch;

   color spotColor, barCol1, barCol2;

   float band, rBar, gBar, bBar;

   void setup() {

   // Set size of window and rendering mode

   // Note: If your machine has OpenGL capabilities, change

   // 'P3D' to 'OPENGL' and uncomment the first line

   size(800, 500, P3D);

   minim = new Minim(this);

   //fs = new SoftFullScreen(this);

   //fs.enter();

   //

   // MODIFY STRING TO CHANGE THE SONG THAT IS LOADED

   // (SONG MUST BE IN soundWaterfall/data/)

   song = minim.loadFile("annArborPart2.mp3", 512);

   song.loop();

   //song = minim.getLineIn(minim.MONO, 2048);

   fft = new FFT(song.bufferSize(), song.sampleRate());

   fft.window(FFT.HAMMING);

   numSpots = 0;

   barCol1 = color(0,0,128,255);

   barCol2 = color(0,0,128,150);

   index = 0;

   colorSwitch = 0;

   rBar = 0;

   gBar = 0;

   bBar = 0;

   }

   void draw() {

   smooth();

   background(0);

   fft.forward(song.mix);

   for(int i = 0; i < 150; i+=2) {

   // GET MAGNITUDE OF FFT AT BAND i

   band = fft.getBand(i);

   spotColor = color(0,0,min(100*band,255));

   // Draw a bar for FFT Band i as well as a reflection of the bar

   stroke(barCol1);

   strokeWeight(4);

   line(width/30 + 5*i, 23*height/26,-width/10, width/30 + 5*i, 23*height/26 - 5*band,-width/10);

   stroke(barCol2);

   strokeWeight(3);

   line(width/30 + 5*i, 93*height/104, -width/10, width/30 + 5*i - 2*band, 93*height/104 + 2*band, band/15 - width/10);

   // Make a spot if the magnitude of the band is big enough

   if((numSpots < MAX_SPOTS) && (index == NUM_ITERATIONS) && (band > 1)) {

   spots[numSpots] = new Spot(5  *width/61 + 5*i, max(2*height/7,103*height/168 - int(4*band)), spotColor);

   numSpots++;

   }

   }

   // RESET INDEX IF IT'S TIME TO GET ANOTHER FFT SAMPLE

   if(index == NUM_ITERATIONS) {

   index = 0;

   }

   else {

   index++;

   }

   // Update the color and position of all spots

   for(int i=0; i < numSpots; i++) {

   spots[i].update();

   if(index == NUM_ITERATIONS) {

   spots[i].colorChange();

   rBar += spots[i].r;

   gBar += spots[i].g;

   bBar += spots[i].b;

   }

   }

   // Update the color of the bars

   if(index == NUM_ITERATIONS) {

   rBar = rBar/(numSpots - 1);

   gBar = gBar/(numSpots - 1);

   bBar = bBar/(numSpots - 1);

   barCol1 = color(rBar,gBar,bBar,255);

   barCol2 = color(rBar,gBar,bBar,150);

   rBar = 0;

   gBar = 0;

   bBar = 0;

   }

   if(numSpots > 80000) {

   numSpots -= 500;

   for(int i=0; i < numSpots; i++) {

   spots[i] = spots[i+499];

   }

   }

   }

   void stop() {

   song.close();

   minim.stop();

   super.stop();

   }

   void mousePressed() {

   numSpots = 0;

   }

   class Spot {

   int x,y,z;

   color c;

   float r, g, b;

   Spot(int tempX, int tempY, color tempC) {

   c = tempC;

   x = tempX;

   y = tempY;

   z = width/15;

   r = red(tempC);

   g = green(tempC);

   b = blue(tempC);

   }

   void update() {

   z -= SPEED/2;

   y += SPEED/20;

   stroke(c);

   strokeWeight(1);

   point(x,y,z);

   //line(y,12*height/21,x,y,z,x);

   }

   void colorChange() {

   if(b > 0 && g == 0) {

   colorSwitch = 0;

   }

   else if(r > 0 && b == 0) {

   colorSwitch = 1;

   }

   else if(g > 0 && r == 0) {

   colorSwitch = 2;

   }

   if(colorSwitch == 0) {

   r++;

   b--;

   }

   else if(colorSwitch == 1) {

   g++;

   r--;

   }

   else if(colorSwitch == 2) {

   b++;

   g--;

   }

   c = color(r,g,b,255);

   }

   }