I'm playing around with moving particles, which are drawn as lines from the previous position to the new one. The problem comes when I zoom in, getting too close to these lines, as the turn from small lines moving inside a 3D space to lines crossing the display from one side to the other, and thus looking like lines in a 2D plane.

After looking into the forum, I thought it would be related to the near z plane clipping distance, so I tried setting a higher distance with perspective(). But it doesnt matter how high I set this distance, it is always looking the same, even setting a near plane distance very close to the far plane distance, all the particles are drawn.

I was using scale() for zooming, so I decided trying camera() instead (just trying here), but Im getting the same problem.

I have created a simple code to show this:

2. firefly[] fireflies = new firefly[20];
3. int lastX=0;
4. int lastY=0;
5. float zoom=1.0;
6. 
   
7. void setup()
8. {
9.   size(300,300, P3D);
10.   smooth();
11.   background(0);
12.   for(int i =0; i< fireflies.length;i++)
13.   {
14.         fireflies[i] = new firefly();
15.   }
16.   float cameraZ =((height/2.0) / tan(PI*60.0/360.0));
17.   perspective(PI/3.0, width/height, cameraZ*9.5, cameraZ*10.0);// ridiculously high near z plane 
18. }
19. 
    
20. void draw(){  
21.  
22.   background(0);
23.   stroke(247,247,82);
24.   //
25.   camera(width/2.0, height/2.0, zoom * (height/2.0) / tan(PI*60.0 / 360.0) , width/2.0, height/2.0, 0, 0, 1, 0);
26.  
27.  //translation for rotating around the centre of the sketch
28.   pushMatrix();
29.   translate(width/2,height/2,0);
30.   rotateX(radians(mouseY%360));
31.   rotateY(radians(mouseX%360));
32.   translate(-width/2, -height/2,0);
33. //  scale(zoom);
34. 
    
35.   for(int i =0; i< fireflies.length;i++)
36.   {
37.         fireflies[i].update(); //update position and draw
38.   }
39.   popMatrix();
40.   println(zoom);
41. }
42. 
    
43. void keyPressed()
44. {
45.   if (key=='a')
46.     zoom+=0.1;
47.   else if (key == 'z')
48.     zoom-=0.1;
49. }
50. class firefly
51. {
52.     int lastX;
53.     int lastY;
54.     int lastZ;
55.     
56.     firefly()
57.     {
58.         lastX=(int)random(0, width);
59.         lastY=(int)random(0, height);
60.         lastZ=(int)random(0, -100);
61.     }
62.     
63.     void update()
64.     {
65.          int newX=(int)(lastX + random(-5,5));
66.          int newY=(int)(lastY + random(-5,5));
67.          int newZ=(int)(lastZ + random(-5,5));
68.          
69.          line(this.lastX,this.lastY, this.lastZ, newX, newY, newZ );
70.          this.lastX=newX;this.lastY=newY;this.lastZ=newZ;
71.     }
72. }

Just move the mouse and press 'z' to zoom in toward the particles to see what I mean. Pardon my rudimentary zoom method.

Any help would be highly appreciated! Thanks!