Simple camera look at point function

[Ywa]

Hi everyone,

 

I've been trying to get a simple camera look at point function working, but I ended up rewriting it 20 times or so. While it's a relatively easy-to-write function.

 

The problem is simple. I have my camera position, and a 3D point to look at. How do I calculate the rotation/angles for the camera? It would be awesome if someone could write an example function (in C++ or any other language), any help is welcome though.

 

Thanks in advance.

 

- Ywa

[Marleys Ghost]

The simplest way would be to create a pivot, move that to the x,y,z co-ordinate you want the camera to point at and then use PointEntity:

 

PointEntity(Camera, Pivot, 3, 1.0, 0.0)

[Ywa]

*slaps himself for never seeing PointEntity*

 

Thanks.

[Clackdor]

I used to need to know trigonometry to point my camera, but then I took a PointEntity() to the knee.

[Ywa]

Edit: Solved. I was so stupid for not calling the SetLookAtPoint function. Thanks guys!

 

I must be doing something wrong. I have this code in my SetLookAtPoint function.

 

procedure CCamera.SetLookAtPoint( vecLookAtPos : TVec3D );
var
 vPivot : TPivot;
begin
 //Hacky method (TODO: Make less hacky)
 vPivot := CreatePivot();
 PositionEntity(vPivot,vecLookAtPos);
 PointEntity(self.Entity,vPivot,3,1.0,0.0);
 FreeEntity(vPivot);
end;

self.Entity is the camera entity

 

The camera doesn't seem to rotate.

[Canardia]

Don't delete the pivot. The camera turns smoothly over many frames, so it needs the pivot for long time.

[Ywa]

Well deleting it seems to work fine, and I don't want it to turn smoothly (I'll do that on my own).