Camera zoom while keeping an off-center object at the same screen co-ordinates

Questions & Answers
1

Camera zoom whiloe keeping an offcenter object at the same screen co-ordinates.

Im doing a zoom by dragging on the highligted red ball below.

How do I get the ball to stay at it’s screen coords while the rest of the view zooms in?

Thanks in advance

James

7894-tabula.jpg
7894-tabula.jpg1656×551 185 KB

7897-tabula2.jpg
7897-tabula2.jpg831×551 146 KB

2

I’ve not got time right now to write the test code, but here is the idea:

  • Use Camera.main.WorldToViewportPoint() before making the move (or even in Start()) to get the position in viewport space of the object.
  • Move the camera in for the zoom.
  • Get the new Viewport coordinates for the new position of the object.
  • Using the new distance between the camera and the board, calculate the world positions for the two viewport positions using Camera.ViewportToWorldPoint();
  • Subtract the two to get how far to translate the board or the camera.