Need some quick trig help, finding a point on a circle

I'm trying to add some orbiting functions to my camera code, and i need a little bit of math help.

The camera is at a fixed offset from the player, in terms of height and absolutedistance, those two variables will not change. So what i basically have is a circle, with the player/focal object in the centre, and my camera sitting at a point on the circumference of that circle.

What i'd like to do therefore, is move the camera along the circumference, by a given distance. And to do that, i need to be able to calculate a point on the circumference a certain distance (or angle?) from my current one. I'm not quite sure where to start there.

Here's a little pictoral example.


Point a is where i'd like to move the camera to. How do i calculate that location? assuming i have the current locations of player and camera.

 

look at the standard asset camera controller, specifically orbit

 

https://en.wikipedia.org/wiki/Polar_coordinate_system - or more specifically https://en.wikipedia.org/wiki/Polar...rting_between_polar_and_Cartesian_coordinates

 

Isnt there a rotatearound function?

 

Check the code in the Unity wiki : http://wiki.unity3d.com/index.php?title=MouseOrbitImproved

similar :
http://wiki.unity3d.com/index.php/MouseOrbitInfiteRotateZoom
http://wiki.unity3d.com/index.php?title=MouseOrbitZoom

 

Haven't done this in a while, but:

1. Take the difference from camera position to player position

Code (csharp):

1. Vector3 difference = player.position - camera.position;

2. Construct a rotation quaternion from the angle you want to rotate by:

Code (csharp):

1. Quaternion rot = Quaternion.Euler(0, angle, 0);  //will rotate around the y axis by angle degrees

3. Rotate your difference vector (multiplying a vector3 by a quaternion rotates it)

Code (csharp):

1. Vector3 rotatedCamPosition = rot * difference;

4. Add the player position back in:

Code (csharp):

1. camera.position = player.position + rotatedCamPosition;

Or, just camera.RotateAround(player.position, Vector3.up, angle);

 

hii x thanks everyone, i was monitoring this thread while doing another project. I've eventually opted for the RotateAround function, which accomplishes this task nicely and with minimal fuss. That's the kind of thing i was looking for,i usually prefer to go with prebuilt native solutions over reinventing the wheel <3