Die Pips

OK, I'm feeling pretty dumb for asking this one, but.... What is the easiest way to determine the value of a physics die when it is rolled? I know it a question of final rotation. And I have the script to determine the rotation after it stops. But how do I turn that rotational value into "which side is up"?

Dont use physics. Anyone can llPushObject your die and mess with the result, or send it offworld.

Actually, you could use physics more safely as a graphical effect, if you pregenerate the random value. This would tamper-proof the result, but people could still orbit your die to the other side of the world, regardless of permissions.

Yup, Eggy's right. As to the maths... the easiest is AxisAngle2Rot, which is way more predictable and intuitive than Euler and also faster because Rots are almost axis/angle.

The way you could do this is:

- face 1 is zero rot: <0,0,0,1>

- faces 2 to 5 are: rotate around z-axis from 0 to 3 times then tilt to one side:

rot rFinalRot = ZERO_ROTATION;
for( int i = 0; i < iFace - 1; i++ )
{
   rFinalRot = llAxisAngle2Rot( <0,0,1>, 90 ) * rFinalRot;
}

rFinalRot = llAxisAngle2Rot( <0,1,0>,90) * rFinalRot;

(note: cant remember if you need to pre or postmultiply rots in SL, just swap the multiplications around if its wrong; ditto with degrees vs radians; just convert to radians if SL expects radians)

And then the last face is simple roatation about x or y axis by 180:

rFinalRot = llAxisAngle2Rot( <0,1,0>, 180 );

Azelda