Re: [Algorithms] Rotating camera to look at a pixel

[Lennart D. <len...@ga...>]

A pixel is just a projected point on the nearplane of the camera,
so you'd just have to find the horizontal and vertical angle between the
camera's forward-vector and the <vector from the camera's origin to the
point-on-the-nearplane>.

I guess...

---

Lennart E. Denninger | Coder

Lost Boys Games | Herengracht 410 | Amsterdam The Netherlands
Tel: +31 (0)20 4272277 | Fax: +31 (0)20 4274040 | Le...@ga...
Amsterdam | Barcelona | Berlin | London | Madrid | Paris | San Francisco |
Warsaw | Zurich | www.games.lostboys.com

---

The most likely way for the world to be destroyed, most experts agree, is by
accident.
That's where we come in; we're computer professionals.
We cause accidents.
----- Original Message ----- 
From: "Josef Grahn" <d0...@na...>
To: <gda...@li...>
Sent: Tuesday, July 01, 2003 3:53 PM
Subject: RE: [Algorithms] Rotating camera to look at a pixel


> On Mon, 30 Jun 2003, Jon Watte wrote:
>
> [...]
> > The problem with making the camera face "a pixel on the screen" is that
> > you need the Z value at that point, else there's a whole (infinite) set
of
> > rotations that all face that pixel, depending on what the depth is
assumed
> > to be at that point.
>
> I am probably not following you right now, but what does the Z value
> has to do with it? A screen space point (the pixel) represents a line
> through that point in the image plane and the projection center of
> the camera. As long as the projection center coincides with the
> rotational center, which I assume it does, this line will always
> correspond to a point in the image plane under rotation. It should
> not be a problem to rotate the camera so that it faces the pixel,
> regardless of the depth value. Still there would be infinitely many
> such rotations since you can roll the camera, but not due to the fact
> the pixel represents a 1D space, right?
>
> Regards,
> Josef
>
>
> >
> > Cheers,
> >
> > / h+
> >
> >
> > > -----Original Message-----
> > > From: gda...@li...
> > > [mailto:gda...@li...]On Behalf Of
Jason
> > > Zisk
> > > Sent: Monday, June 30, 2003 12:17 PM
> > > To: gdalgo
> > > Subject: [Algorithms] Rotating camera to look at a pixel
> > >
> > >
> > > I'm having trouble coming up with a method to rotate the camera
> > > to look at a
> > > particular pixel on the screen.  Basically I have an x, y point in
screen
> > > coordinates (this point may or may not actually be on the screen, it
could
> > > be negative for instance), and I want to rotate the camera to ensure
that
> > > pixel is in the center of view.  Keep in mind I can only rotate
> > > the camera.
> > >
> > > I'm doing some work with imposters and this seems to be the best way
to go
> > > about capturing the imposter image.  I've got the screen-space
> > > bounding box
> > > around the object so its easy finding the center pixel, just the next
step
> > > of getting the camera to look at that pixel is eluding me.
> > >
> > > Thanks for any help,
> > >
> > > - Jason Zisk
> > > - nFusion Interactive LLC
> > >
> > >
> > >
> > >
> > >
> > > -------------------------------------------------------
> > > This SF.Net email sponsored by: Free pre-built ASP.NET sites including
> > > Data Reports, E-commerce, Portals, and Forums are available now.
> > > Download today and enter to win an XBOX or Visual Studio .NET.
> > >
http://aspnet.click-url.com/go/psa00100006ave/direct;at.asp_061203_01/01
> > > _______________________________________________
> > > GDAlgorithms-list mailing list
> > > GDA...@li...
> > > https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list
> > > Archives:
> > > http://sourceforge.net/mailarchive/forum.php?forum_id=6188
> > >
> >
> >
> >
> > -------------------------------------------------------
> > This SF.Net email sponsored by: Free pre-built ASP.NET sites including
> > Data Reports, E-commerce, Portals, and Forums are available now.
> > Download today and enter to win an XBOX or Visual Studio .NET.
> > http://aspnet.click-url.com/go/psa00100006ave/direct;at.asp_061203_01/01
> > _______________________________________________
> > GDAlgorithms-list mailing list
> > GDA...@li...
> > https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list
> > Archives:
> > http://sourceforge.net/mailarchive/forum.php?forum_ida88
> >
>
>
>
> -------------------------------------------------------
> This SF.Net email sponsored by: Free pre-built ASP.NET sites including
> Data Reports, E-commerce, Portals, and Forums are available now.
> Download today and enter to win an XBOX or Visual Studio .NET.
> http://aspnet.click-url.com/go/psa00100006ave/direct;at.asp_061203_01/01
> _______________________________________________
> GDAlgorithms-list mailing list
> GDA...@li...
> https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list
> Archives:
> http://sourceforge.net/mailarchive/forum.php?forum_id=6188