If I have the view matrix, can I find the camera's target point?


#1

How do you find the point that camera is aiming at, if I have the view matrix? I have the eye position and the camera orientation but I need to know the ‘lookat’ point, if there is one?


#2

The camera doesn’t look at a point. The camera looks along a direction; there are infinitely many points along that direction that the camera could be looking at.

Look-at-style functions will generate the same matrix for any of the points in that direction. They only take a point because some people find that it’s easier to orient a camera to look at a position.


#3

Okay, thanks - I was afraid that was the answer.


#4

Invert the view matrix. Transform the points (0,0,0,1) and (0,0,-1,1) by the inverse of the view matrix. The first point gives you the eye position, the second gives you a point directly in front of the camera. The line through those two points is the centre line of the view.