stuck with 360 camera loop

[uwi2k2]

hi all,

sorry , but i just got stuck with a free 360 camera movement.
right now i can move left / right at full 360 .. but the up and down holds at -90 / + 90 degree.
here is what i do right now:

      this.Control.yrotrad = (this.Control.yrot / 180.0 * 3.141592654 );
      this.Control.xrotrad = (this.Control.xrot / 180.0 * 3.141592654 );
 
      // up vector
      this.up[0]    = 0.0;
      this.up[1]    = 1.0;
      this.up[2]    = 0.0;      
 
      // eye
      this.eye[0]    = this.Control.xpos;
      this.eye[1]    = this.Control.ypos;
      this.eye[2]    = this.Control.zpos ;  
 
      // center point
      this.center[0] =  this.Control.xpos+(Math.sin(this.Control.yrotrad)*1.0);
      this.center[1] =  (this.Control.ypos-(Math.sin(this.Control.xrotrad)*1.0));
      this.center[2] =  this.Control.zpos-(Math.cos(this.Control.yrotrad)*1.0) ;    
 
      this.myWGL.CameraView     = M4x4.makeLookAt ( this.eye,  this.center, this.up );

i guess its all about the up vector .. but i just can´t figure out what to do ...
can someone complete the code ? or am i going the wrong way ?

thanx
uwi

[GClements]

i guess its all about the up vector .. but i just can´t figure out what to do ...
can someone complete the code ? or am i going the wrong way ?

If you want direct control over the view direction, using a "look-at" function is probably the wrong way to go about it. It's simpler to concatenate a translation, a rotation about the vertical axis and a rotation about the left-right axis. Also, the look-at approach has undefined behaviour if you're looking directly up or down.

A pitch angle of more than +/- 90 degrees will make the view upside down, which is impossible to achieve with a fixed up vector (it will combine a 180-degree rotation about the vertical axis with a pitch wrapped to the -90..+90 range).

But if you're committed to the look-at approach, you can just invert the up vector when the pitch is outside of that range.