Remove left-click requirement to move camera in PeasyCam

I am working on a Minecraft clone developed using Processing and PeasyCam. I will code the rest myself, with help from this forum. I need to know how to track mouse movement without having to left-click. That will be used for a first-person look-around feature. Here is the code right now:

import peasy.PeasyCam;

PeasyCam cam;

final float gravity = 1; //Inaccurate gravity simulation (impulse rather than force)

// ArrayLists for the class
//ArrayList<Box3D> boxes = new ArrayList(); 
//Box3D box;

// this is a very important size: size boxes
float sizeBox = 70.0;
float sizeLimit = 180;

float rotationX;
float rotationY;
float rotationZ;

float translatex=-sizeBox;
float translatey=-sizeBox;
float translatez=0;

float z = 1.0;

int objectNumber = 0;

// folded triangle 
PShape s; 

float offsetZ=400;

color colCurrent=color(0, 0, 255);

boolean showHelpText=true; 

void setup() {

  size(500, 500, P3D);
  background(0);
  sphereDetail(32);

  cam = new PeasyCam(this, 400); // new
  //box = new Box3D(0, 0, 0, 0, 0, color(255));

  s = createShape();
  s.beginShape();
  s.fill(255, 0, 0);
  s.stroke(177);
  s.vertex(100, 0, -100);
  s.vertex(-60, 0, 200);
  s.vertex(-50, 60, -30);
  s.vertex(110, 160, 40);
  s.scale(0.4);
  s.endShape(CLOSE);
}

void draw() {
  background(0);
  lights();

  //for (Box3D b : boxes ) {
   // box.display();
  //}

  noFill();
  box(sizeLimit*2+sizeBox); // ?

  showObject();

  cam.beginHUD(); 
  /**if (showHelpText) {
    fill(255); // white 
    text ("Use PeasyCam. Use wasd and pl; r/g/b for colors, space bar to toggle object, RETURN to enter object to list.\n\n"
      +"Use x to switch this text on and off. \n"
      +"Use Mousewheel to zoom, double click to reset view. The box you move has a white outline. An item that has been added to the list is marked with a gray box.\n"
      +"On adding to the list the placing box moves two units left. \n"
      +"Current: "
      +translatex
      +", "
      +translatey
      +", "
      +translatez, 
      19, 19);
  }*/ //HUD disabled

  if (keyPressed)
    keyPressed_ForContinuusKeyinput();

  cam.endHUD();
}

// -----------------------------------------------------------

void showObject() {

  // show object 

  pushMatrix();

  translatey+=gravity;

  translatex=constrain(translatex,-sizeLimit,sizeLimit);
  translatey=constrain(translatey,-sizeLimit,sizeLimit);
  translatez=constrain(translatez,-sizeLimit,sizeLimit);

  fill(colCurrent); // color
  //translate(width/3, height/2, 0);
  translate(translatex, translatey, translatez);
  //rotateZ(rotationZ);
  //rotateY(rotationY);
  //rotateX(rotationX);

  stroke(255); 

  if (objectNumber==0) {
    //stroke(111);
    box(sizeBox);
  } else if (objectNumber==1) {
    s.setFill(colCurrent);
    shape(s, 0, 0);
  } else if (objectNumber==2) {
    //noStroke();
    sphere(sizeBox);
  }//else 

  popMatrix();
}

// -----------------------------------------------------------

void keyPressed_ForContinuusKeyinput() {
  // keyPressed for registering a key throughout  

  float speed = 3.9; 

  //speed += gravity; //More accurate gravity simulation, may be removed

  switch(key) {

  case 'a':
    translatex-=speed;
    break; 

  case 'd':
    translatex+=speed;
    break;

  case 'w':
  case ' ':
    translatey-=speed; //Conflicting keypress info: change object
    break;

  case SHIFT:
  case 's':
    translatey+=speed;
    break;

    // --

  case 'p':
    translatez-=speed;
    break; //Unnecessary in 2D version, but useful

  case 'l':
    translatez+=speed;
    break; //Unnecessary in 2D version, but useful

    // -----

    //
  }//switch
  //
}//func

// ----------------------------

void keyPressed() {

  // keyPressed for registering a single key only 

  switch(key) {
    /**
  case ' ':
    objectNumber++;
    if (objectNumber>2)
      objectNumber=0;
    key=0;
    break;
    */ //Object switch disabled in favor of jumping

 /**
  case RETURN:
  case ENTER:
    Box3D newBox = new Box3D (
      translatex, 
      translatey, 
      translatez, 
      rotationY, 
      objectNumber, 
      colCurrent
      ); 
    boxes.add(newBox); 
    translatex-=sizeBox*2;
    break;
    */ //New object function disabled

    // ---
    //colors

  case 'r':
    colCurrent=color(255, 0, 0);
    break;

  case 'b':
    colCurrent=color(0, 0, 255);
    break;

  case 'g':
    colCurrent=color(0, 255, 0);
    break;

    // --

  case 'x':
    showHelpText = !showHelpText; 
    break;
  }//switch
  //
} //func

//=============================================================

class Box3D {

  float x=mouseX, y=410, z=mouseY;

  float offsetX=0; 
  float offsetZ2=0; 

  float rotateY=0;
  color colBox = color(255, 0, 0);

  // type
  final int boxTypeUndefined = -1;
  final int boxType0   = 0;
  final int boxType1   = 1; 
  final int boxType2   = 2; 
  // more needed !!!!! ???? 
  int type = boxTypeUndefined; 

  // constr - full
  Box3D(float x_, 
    float y_, 
    float z_, 
    float rotateY_, 
    int type_, 
    color col1_) {
    //

    x=x_;
    y=y_;
    z=z_;

    rotateY= rotateY_;
    type=type_;

    colBox=col1_;
  } // constr 2 

  void display() {
    pushMatrix();

    translate(x, y, z);
    //  rotateY(radians(rotateY)); 

    fill(colBox);
    noStroke(); 

    // depending on the current buttons tag 
    // 
    switch (type) {

    case boxTypeUndefined:
      // undefined 
      break; 

    case boxType0: 
      stroke(111);
      box(sizeBox);
      break; 

    case boxType1: 
      s.setFill(colBox);
      shape(s, 0, 0);
      break;

    case boxType2: 
      noStroke();
      sphere(sizeBox);
      break;

    default:
      // error 
      break;
    }//switch 

    if (showHelpText) {
      translate(sizeBox/2, -sizeBox/2, sizeBox/2);

      fill(111);
      stroke(0);
      box(sizeBox/6);
    }

    popMatrix();
  } // method 

  String toString() {
    return
      str(x) +","+ 
      str(y) +","+ 
      str(z) +","+ 
      str(rotateY) +","+ 
      str(type) +","+ 
      str(red(colBox)) +","+ 
      str(green(colBox)) +","+ 
      str(blue(colBox)) ;
  }
  //
} // class 
//

I understand there is a redundant class "Box3D", but I will handle that before implementing whatever solution you give me.