Hi,

it's probably not too complicated but I can't find the solution. I'm looking for a quick way to fit a 3d object into the view.
I found a not so nice solution with the help of screenX etc, but I have to make a loop until I have the camera at the right z position.  I couldn't find the formula to directly calculate  the correct z distance. I would appreciate any help or ideas

phil

I have code that does this, but I'll have to dig it up.  Basically though, it's a two part process:

First, you need to figure out a bounding box around your object(s), this can be the hard part if the object is arbitrarily rotated.  But let's just assume that you have a "bbox" object with min/max/center/dimensions already calc'd and ready to go, so I can fake up some code for ya...

Second, fitting the bbox to the display is the easy part.  You know the field of view (g.cameraFOV = 60 degrees), and one side of the triangle (bbox width or height), and you're solving for the other side (z distance).  So you plug in twice for the x and y extents of the box and take the further distance.  (because aspect of bounding box may not match screen)

Off the top of my head, psuedocode, something like:

float zdistW = (bbox.width/2f) / tan(g.cameraFOV/2f);
float zdistH = (bbox.height/2f) / tan(g.cameraFOV/2f);
float zdist = max(zdistW, zdistH);

// then put your camera here:
float eyeX = bbox.centerX;
float eyeY = bbox.centerY;
float eyeZ = bbox.maxZ + zdist;

You might want to add a tiny bit of additional fudge factor and zoom out a bit further, otherwise any objects right at the near face of the bbox might be zoomed TOO tight to the screen edges.