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uwi2k2
08-10-2013, 08:14 AM
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 canīt figure out what to do ...
can someone complete the code ? or am i going the wrong way ?

thanx
uwi

GClements
08-10-2013, 07:09 PM
i guess its all about the up vector .. but i just canīt 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.