llRot2Left

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Revision as of 17:35, 20 July 2012 by Acheron Gloom (talk | contribs) (Added a note to remind people that they can use <0.0, 1.0, 0.0>*rot instead of llRot2Left(rot) with unit quaternions. I always see people using llRot2* in fast-running code when it can be simplified.)
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Summary

Function: vector llRot2Left( rotation q );
0.0 Forced Delay
10.0 Energy

Computes the orientation of the local y-axis relative to the earth.
Returns a vector that is the left vector defined by q, i.e. a unit vector pointing in the local positive Y direction

• rotation q

Can be useful to identify the orientation of the local "Wikipedia logo"sagittal-plane of the prim, since it's y-axis is always perpendicular to this local sagittal-plane.

Specification

Mathematically equivalent to: <lsl>ret = llVecNorm(<0., 1., 0.> * q);</lsl> If q is known to be a unit quaternion then it can be simplified as: <lsl>ret = <0., 1., 0.> * q;</lsl> Keep in mind that object and agent rotations will always be unit quaternions. For example, <0.0, 1.0, 0.0>*llGetRot() is about 25-30% faster than llRot2Left(llGetRot()) depending on the VM used. If done often and at extremely fast rates, it can be advantageous to even save <0.0, 1.0, 0.0> to a local/global variable and reuse it.

Examples

See Also

Functions

•  llRot2Up
•  llRot2Fwd
•  llRot2Axis
•  llRot2Angle

Deep Notes

Signature

function vector llRot2Left( rotation q );