llRot2Up
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Summary
Function: vector llRot2Up( rotation q );20 | Function ID |
0.0 | Forced Delay |
10.0 | Energy |
Computes the orientation of the local z-axis relative to the parent (i.e. the root prim or the world).
Returns a vector that is the up vector defined by q, i.e. a unit vector pointing in the positive Z direction
• rotation | q |
Specification
Mathematically equivalent to:
ret = llVecNorm(<0., 0., 1.> * q);
If q is known to be a unit quaternion then it can be simplified as:
ret = <0., 0., 1.> * q;
Keep in mind that object and agent rotations will always be unit quaternions. For example, <0.0, 0.0, 1.0>*llGetRot() is about 25-30% faster than llRot2Up(llGetRot()) depending on the VM used. If done often and at extremely fast rates, it can be advantageous to even save <0.0, 0.0, 1.0> to a local/global variable and reuse it.
Caveats
Examples
// Move a prim 5 metres forwards along its own z axis, when touched, no matter how the object is oriented in world.
// Works for a root or child prim
default
{
touch_start(integer total_number)
{
vector v = llRot2Up( llGetLocalRot() );
llSetPos( llGetLocalPos() + v * 5 );
}
}
Notes
Can be useful to identify the orientation of the local horizontal-plane of the prim, since it's z-axis is always perpendicular to this local horizontal plane.
See Also
Functions
• | llRot2Left | |||
• | llRot2Fwd | |||
• | llRot2Axis | |||
• | llRot2Angle |