hello,

i've got a problem that seems to be simple but its gonna drive me crazy. I want to use face-tracking to control the camera in a 3d-scene. that works quite fine except one thing. the face-tracking example simply draws a rectangle around my head. if i come closer to the monitor the rectangangle becomes bigger thats clear. to control the z-position of the camera i use the size of this rectangle. that works but is there a way to tell him, that the z-position decreases while the height of the rectangle increases? if i set the var negative, it just flips to the negative z-area. do you know what i mean. maybe you could try it yourself. the lib is installed in a minute   . this is my code, i know theres a lot to optimize and to clean up but i'm new with processing and still learning...

Code:

import hypermedia.video.*;
import processing.opengl.*;
import codeanticode.glgraphics.*;

OpenCV opencv;

PFont futura;
float z = 0;
float camX = 0;
float camY = 0;
float camZ = 1000.0;
float camCenterY = 0;
float camCenterX = 0;
float camCenterZ = 0;
float a = -500;
boolean changedir = false;
float linerotone = 0;
float linerottwo = 0;
int side = 0;
float tr;

void setup() {
  size(1024 , 768, OPENGL);
  opencv = new OpenCV( this );
  opencv.capture( width/4, height/4 );			 // open video stream
  opencv.cascade( OpenCV.CASCADE_FRONTALFACE_ALT_TREE );  // load detection description, here-> front face detection : "haarcascade_frontalface_alt.xml"
  futura = createFont("DIN-Bold", 48);
  fill(204);
  frameRate(30);
  smooth();
}

void draw() {
  background(0);
  opencv.read();
  opencv.convert( GRAY );

  Rectangle[] faces = opencv.detect( 1.2, 2, OpenCV.HAAR_DO_CANNY_PRUNING, 40, 40 );
  image( opencv.image(), 0, 0 );

  lights();
  noFill();
  stroke(0,0,255);
  strokeWeight(1);
    for( int i=0; i<faces.length; i++ ) {
	rect( faces[i].x, faces[i].y, faces[i].width, faces[i].height ); 
	camX = round(-(-width/2+faces[i].x*4)*HALF_PI);
	camCenterX = (faces[i].x);
	camY = round(((-height/2+faces[i].y*4)*HALF_PI)+200);
	camCenterY = round(faces[i].y);
	//z = faces[i].height*10;
	camCenterZ = -z;
	//camCenterZ = 0.0;
	//z = dist(camX,camY,faces[i].height*10,camCenterX,camCenterY,camCenterZ);
	z = mag(0,faces[i].height*10);
	float distance = z;
	println(z);
	camZ = distance;
    }

  perspective();

  // Change height of the camera with facedetect
  camera(camX , camY, camZ, // eyeX, eyeY, eyeZ
  camCenterX, camCenterY, camCenterZ, // centerX, centerY, centerZ
  0.0 , 1.0, 0.0); // upX, upY, upZ
  //ambientLight(100, 50, 50);
  directionalLight(255,255,255,-1,0.5,0);

  if(keyPressed){
    if(key == 's'){
	camZ+=10;
    }
    else if(key == 'w'){
	camZ-=10.0;
    }
  }
  noFill();
  pushMatrix();
  fill(255,50);
  pushMatrix();
  translate(2000,300,2000);
  rotateX(HALF_PI);
  rect(-4000,-4000,4000,4000);
  popMatrix();
  for(int side = 0; side<2000; side+=200){
    stroke(125);
    strokeWeight(2);
    line(-(side),100,-(side),side,100,-(side));
    line(side,100,-(side),side,100,side);
    line(side,100,side,-(side),100,side);
    line(-(side),100,side,-(side),100,-side);
  }
  popMatrix();
  pushMatrix();
  line(-2000,100,-2000,2000,100,2000);
  line(2000,100,-2000,-2000,100,2000);
  popMatrix();


  strokeWeight(6);
  linerotone+=0.01;
  pushMatrix();
  rotateZ(linerotone);
  stroke(200,0,0);
  line(10,10,0,0,180,0);
  pushMatrix();
  translate(0,180,0);
  noStroke();
  fill(255);
  sphere(20);
  popMatrix();
  stroke(200,0,0);
  line(-10,-10,0,0,-180,0);
  pushMatrix();
  translate(0,-180,0);
  noStroke();
  fill(255);
  sphere(20);
  popMatrix();
  popMatrix();
  pushMatrix();
  rotateZ(linerotone*(-PI/2));
  stroke(200,0,0);
  line(10,10,0,0,200,-200);
  pushMatrix();
  translate(0,200,-200);
  noStroke();
  fill(255);
  sphere(20);
  popMatrix();
  stroke(200,0,0);
  line(-10,-10,0,0,-200,200);
  pushMatrix();
  translate(0,-200,200);
  noStroke();
  fill(255);
  sphere(20);
  popMatrix();
  popMatrix();
  linerottwo-=0.01;
  pushMatrix();
  rotateZ(linerotone*(PI/8));
  stroke(200,0,0);
  line(10,10,0,0,200,-400);
  pushMatrix();
  translate(0,200,-400);
  noStroke();
  fill(255);
  sphere(20);
  popMatrix();
  stroke(200,0,0);
  line(-10,-10,0,0,-200,400);
  pushMatrix();
  translate(0,-200,400);
  noStroke();
  fill(255);
  sphere(20);
  popMatrix();
  popMatrix();
  pushMatrix();
  rotateZ(linerotone*(-PI/16));
  stroke(200,0,0);
  line(10,10,0,0,200,-600);
  pushMatrix();
  translate(0,200,-600);
  noStroke();
  fill(255);
  sphere(20);
  popMatrix();
  stroke(200,0,0);
  line(-10,-10,0,0,-200,600);
  pushMatrix();
  translate(0,-200,600);
  noStroke();
  fill(255);
  sphere(20);
  popMatrix();
  popMatrix();

  noStroke();
  fill(0,255,0);
  if(changedir == false){
    a+=5;
  }
  if(a>=500){
    changedir = true;
  }
  if(changedir == true){
    a-=5;
  }
  if(a<=-500){
    changedir = false;
  }
  tr+=0.005;
  rotateY(tr);
  textFont(futura);
  text("...wir sind im Besitz der Mittel, aber ohne Idee!",-400,0,a);
  //println(frameRate);

}