Re: [Plib-users] ssg camera woes / tranformation/coordsystem confusion

[Jakob G. <pi...@st...>]

Thank you very very much!
   This was the only thing I hadn't considered...
Considering the totally different directions I was looking for the =
problem in,
you've saved me very much frustration...
  ----- Original Message -----=20
  From: Eduardo Alberto Hern=E1ndez Mu=F1oz=20
  To: pli...@li...=20
  Sent: Sunday, February 12, 2006 9:48 PM
  Subject: Re: [Plib-users] ssg camera woes / tranformation/coordsystem =
confusion


    Hi. I have some pre-SSG/own code, I'm trying to migrate to SSG.=20
    However, my camera code screws up; it's as if the axes are switched, =
or
    worse.

    For example, my code has a direction/rotation matrix, that indicates
    the users' rotation around the y axis (it could be a rotation angle =
instead,=20
    but I'm exploiting that it's a matrix).

    However, when I multiply this matrix onto the ssg camera, it rotates =
around
    the _Z_ axis instead!
      Similar problems happen with other parts of the transform (which =
I've=20
    commented out to dissect the problem).


  This is a quote from a page at Steve Baker's tuxkart site at =
http://tuxkart.sourceforge.net/trackdesign.html :

  "I come from a flight-simulation background where we use the =
convention that Z-is-up - so all my software works like that. However, =
the PLIB loaders know that some modellers use Y-is-up and do the axis =
swap as needed. Hence, in AC3D, Y-is-up - but in the game, your models =
will be converted to Z-is-up. If you find this confusing, forget I =
mentioned it - everything comes out OK automagically."

  So I would beleive the Z axis is the Y axis are swapped in plib, so =
just swapping these values when you load models and in your coordinate =
handling code would do the trick.

  -Coz



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