hello people outthere,
I´ve tried a function with "atan2()" to rotate objects (in this case "rects") 3-dimensional in positioning to the mouse (but it could be any other position as well). First I thought that could work, but as I made a test by drawing a "box" on the "rects", that have always the same height as the distance from the position of the rect to the position of the mouse, I saw it doesnt: when it would be right, the top of the boxes should all meet at the position of the mouse (ellipse).

Is there a way to handle it with "atan2()"? What do you suggest?

have a look! Thanks!!

1. import processing.opengl.*;
   
       ArrayList<myRect> rectlist = new ArrayList<myRect>();
       int rectsize = 100;
       int myBorder = 6;
       int myDepth = -100;
   
       void setup(){
           size(300,300, OPENGL);
           smooth();
           rectMode(CENTER);
           ellipseMode(CENTER);
           for(int i = rectsize; i<width; i+=rectsize){
               for(int e = rectsize; e<height; e+=rectsize){
                   rectlist.add(new myRect(i, e));  
               }
           }
       }
     
       void draw(){
           background(255);
         
           for (int i = 0; i<rectlist.size(); i++){
               rectlist.get(i).display();
           }
         
           ellipse(mouseX, mouseY, 10,10);
       }
   
   /*class of rotating objects*/
   class myRect {
       float x,y,z, mySize,xR, yR, zR, myDist;
     
       myRect(float _x, float _y){
           x = _x;
           y = _y;
           z = myDepth;
           mySize = rectsize-myBorder;
       }
     
       void display(){
         
           myDist = dist(x,y,z,mouseX, mouseY,0);
         
           xR = func_rotateX(y, z)+HALF_PI;
           yR = func_rotateY(x, z)+HALF_PI;
         
           stroke(0);
           strokeWeight(2);
   
           pushMatrix();
           translate(x,y,z);
           rotateX(xR);
           rotateY(yR);
         
           noFill();
           rect(0,0,mySize, mySize);
         
           fill(0);
           strokeWeight(1);
           stroke(0,100);
           ellipse(0, 0, 10, 10);
         
           fill(255,0,0);
           ellipse(-mySize/2, -mySize/2, 10, 10);
           ellipse(mySize/2, mySize/2, 10, 10);
           ellipse(-mySize/2, mySize/2, 10, 10);
           ellipse(mySize/2, -mySize/2, 10, 10);
         
           noStroke();
           translate(0,0,myDist/2);
                   /*testbox: to check if the 3D orientation works, the boxes should meet at the mouse*/
           box(2, 2, myDist);
         
           popMatrix();
   
       }
   
          /*important functions for the orientation*/
       float func_rotateX(float _y, float _z) {
           return atan2(0-_z,mouseY-_y);
       }
   
       float func_rotateY(float _x, float _z) {
               return atan2(0-_z,mouseX-_x);
       }
         
   }