Difference between revisions of "LlRot2Left"
(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.) |
Omei Qunhua (talk | contribs) (Provide an example) |
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|caveats | |caveats | ||
|constants | |constants | ||
|examples | |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> | |||
|helpers | |helpers | ||
|also_functions={{LSL DefineRow||[[llRot2Up]]|}} | |also_functions={{LSL DefineRow||[[llRot2Up]]|}} | ||
Revision as of 07:57, 6 December 2013
| LSL Portal | Functions | Events | Types | Operators | Constants | Flow Control | Script Library | Categorized Library | Tutorials |
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 
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
<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 |
Deep Notes
Signature |
|---|
function vector llRot2Left( rotation q ); |