I'm setting up head tracking and want objects on the projection screen to appear the same size that they would be in the real world. I'm using this formula to do it:
- Code: Select all
d = tracked distance from head (eye) to screen
h = height of screen
fov = 2 * atan (h / 2d)
with a screen height of 7.5 and standing at 5 feet away, that gives me an FOV of 1.287 or around 73 degrees.
I place the camera at (0,0,0) and draw a 1-unit cube at (0,5,0). Now, I'm not sure if that should be a 1 foot, or 1 meter, or 1 what cube, but it's enormous and fills the whole screen. Do I need to set those camera parameters in millimeters instead? And if so, should I be positioning objects in millimeters as well?