llRot2Left
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Summary
Function: vector llRot2Left( rotation q );19 | Function ID |
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 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.
Caveats
Examples
<lsl> // Move an object 5 metres forwards along its own y axis, when touched, no matter how the object is oriented in world. default {
touch_start(integer total_number) { vector v = llRot2Left( llGetRot() ); llSetPos( llGetPos() + v * 5.0 ); }
}
</lsl>See Also
Functions
• | llRot2Up | |||
• | llRot2Fwd | |||
• | llRot2Axis | |||
• | llRot2Angle |