Aug 19, 2011 at 5:31 PM
Edited Aug 19, 2011 at 5:39 PM

I'm working with the windows phone 7 sample, and I wanted to figure out where the center of the projected object is in screen coordinates (x,y). Its been a while since I've worked with linear algebra and any help would be much appreciated!
// Calculate the complete transformation matrix based on the first detection result
var world = centerAtOrigin * scale * randomizedTranslation * dr[0].Transformation;
// Calculate the final transformation matrix by using the camera projection matrix
var m = Matrix3DFactory.CreateViewportProjection(world, Matrix3D.Identity, arDetector.Projection, viewport);
Thanks in advance!
Urvish



The upper left corner of the marker in screen space is:
x = m.OffsetX / m.M44;
y = m.OffsetY / m.M44;
This formula will also give you the position of the marker's center, if you first remove the centerAtOrigin term from your world calculation.

