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Projection Offset Problem

Joshua Eirman · 2019-05-10T21:17:21

I ham having problems understanding a projection and have attached an image to illustrate. The point can be found by: Zfar / (Zfar-Znear) and subtracting (Zfar * Znear) / (Zfar-Znear) The subtracted fraction is what I don't understand. It is an offset of the transformed point and is a discrepancy. Apparently it is pretty easily understood, but I don't understand it. Could somebody please explain? I have a feeling that I still won't understand it, so easy does it, please! Thank you, Josheir

Math and Physics Programming C++

Started by Josheir May 09, 2019 06:08 PM

13 comments, last by ReaperSMS 5 years, 1 month ago

fleabay

1,327

May 10, 2019 07:21 PM

1 hour ago, Josheir said:

No, it's from a video that creates a 3d engine from scratch :

That doens't change the fact that it is very similar, if not exact, to a DirectX projection matrix.

🙂🙂🙂🙂🙂<←The tone posse, ready for action.

Josheir

489

Author

May 10, 2019 07:24 PM

1 minute ago, fleabay said:

That doens't change the fact that it is very similar, if not exact, to a DirectX projection matrix.

I misunderstood the point. Something else I may research than.

Josheir

489

Author

May 10, 2019 09:10 PM

I understand now, be happy!

On ‎5‎/‎9‎/‎2019 at 4:37 PM, ReaperSMS said:

If it is an orthographic projection, we're done. If it is a perspective projection, we must take into account the divide by Zin that will happen.

Why's that, why does orthographic projection have no division and perspective projection does have division?

Josheir