Use the camera() method to change where you're looking from and what direction you're facing.

Still want to know whether it is possible to manipulate the perspective (as described above) or not? If so, what should I do???

Thank you.

i think you might need to draw us a picture...

Ok here is a picture...hope it visualizes my question in a better way. The left side shows the correct perspective like processing does normally...and the right side demonstrates what I want to get > manipulated perspective distortion.

Possible or not?






Thanks for any idea.

i'm wondering whether you can change the camera position and lookat for each box, to one that is centred on the box and looking along z.

1. // DOES NOT WORK 8)
   
2. void setup() {
3.   size(400, 400, P3D);
4.   noFill();
5.   noLoop();
6. }
7. void draw() {
8.   for (int i = 0 ; i < 5 ; i++) {
9.     float x = random(400);
10.     float y = random(400);
11.     stroke(random(128, 192));
12.     camera(x, y, 100, x, y, -100, 0, 1, 0);
13.     translate(x, y, 0);
14.     box(40);
15.   }
16. }

doesn't work - moving the camea the same amount as the box centres the box, so all boxes appear on top of each other...

you could write your own perspective transform, one that only uses y and not y and x, and apply that everywhere. depends on what you;re going to do with your boxes...

You can certainly do this if you've willing to make the camera relative to each object. So instead of the usual pattern

here i've completely faked the perspective, it's hard coded and will only work if everything's facing forwards. depends what you want...

1. void setup() {
2.   size(400, 400, P3D);
3.   noFill();
4.   noLoop();
5. }
6. void draw() {
7.   for (int i = 0 ; i < 5 ; i++) {
8.     float x = random(400);
9.     float y = random(400);
10.     stroke(random(128, 192));
11.     myBox(x, y, 40);
12.   }
13. }
14. void myBox(float x, float y, float sz) {
15.   float s1 = sz / 2;
16.   // front face
17.   line(x - s1, y - s1, x - s1, y + s1);
18.   line(x - s1, y + s1, x + s1, y + s1);
19.   line(x + s1, y + s1, x + s1, y - s1);
20.   line(x + s1, y - s1, x - s1, y - s1);
21.   // back face
22.   float s2 = sz * .4;
23.   line(x - s2, y - s2, x - s2, y + s2);
24.   line(x - s2, y + s2, x + s2, y + s2);
25.   line(x + s2, y + s2, x + s2, y - s2);
26.   line(x + s2, y - s2, x - s2, y - s2);
27.   // sides
28.   line(x - s1, y - s1, x - s2, y - s2);
29.   line(x - s1, y + s1, x - s2, y + s2);
30.   line(x + s1, y - s1, x + s2, y - s2);
31.   line(x + s1, y + s1, x + s2, y + s2);
32. }

> It should only demonstrate what I mean with “perspective distortion”.

then it wasn't a good demonstration 8)

i think you're going to need to write your own rotate routines (they are simple), then use something like the above. your problem is you are using P3D to get access to box and rotateX but that's going to insist on using the default perspective transform which isn't what you want.

there is a perspective() method but i couldn't get that to do what you want. ditto frustum() and ortho(). maybe applyMatrix() would work...

1. ortho(-width/2, width/2, -height/2, height/2, -10000, 10000);