Proyecting 3D point to camera (2D)

I have ported the Ogre wiki page with snippet to convert 3D points to 2D point proyected to camera.

http://www.ogre3d.org/wiki/index.php/MOGRE_Projecting_3D_position_to_2D


// using MOGRE;
// returns a vector with x,y with clamped screencoords in [-1;1]

public Vector2 ProjectPos (Camera cam, Vector3 pos)
{
Vector2 ret = new Vector2();

Vector3 eyeSpacePos = cam.GetViewMatrix(true) * pos;
if (eyeSpacePos.z < 0)
{
Vector3 screenSpacePos = cam.ProjectionMatrix * eyeSpacePos;
ret.x = screenSpacePos.x;
ret.y = screenSpacePos.y;
}
else
{
ret.x = (-eyeSpacePos.x > 0) ? -1 : 1;
ret.y = (-eyeSpacePos.y > 0) ? -1 : 1;
}

return ret;
}


Using Mogre 1.7

I used exactly this function and I am getting very strange results. I pass the camera object and the scene node position for the object I want to overlay. I am wondering though, since i don't fully understand what the function is doing yet, is the fact that my camera object is a child of a scene node possibly causing issues? The camera's position stays at 0,0,0 because of this, but I dont see it effecting the view matrix. The x and y values it remain at -1 and -1 when I'm looking right at the target. the eyeSpacePos.z is at -7687.49, I amm looking at it on the positive x side, the target has a higher x position value and I', looking close to down the x axis at the target.

I'll keep playing with it in the meantime.

FYI, I have it working, I'll post the changes I made to make it work for me, when I'm not so exausted. I'm prolly using it wrong, but it still works

Thanks for this useful code snippet and also for creating a related wiki page

Improvements by dannypb (or others) are welcome.
Please don't just the changes here, update the code in the wiki, too.