Difference between revisions of "LlRot2Up"
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(Added a note to remind people that they can use <0.0, 0.0, 1.0>*rot instead of llRot2Up(rot) with unit quaternions. I always see people using llRot2* in fast-running code when it can be simplified.) |
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|func=llRot2Up|sort=Rot2Up | |func=llRot2Up|sort=Rot2Up | ||
|return_type=vector|p1_type=rotation|p1_name=q | |return_type=vector|p1_type=rotation|p1_name=q | ||
|func_desc=Computes the orientation of the {{HoverText|local z-axis|up-direction of prim}} relative to | |func_desc=Computes the orientation of the {{HoverText|local z-axis|up-direction of prim}} relative to the parent (i.e. the root prim or the world). | ||
|return_text=that is the up vector defined by {{LSLP|q}}, i.e. a unit vector pointing in the positive Z direction | |return_text=that is the up vector defined by {{LSLP|q}}, i.e. a unit vector pointing in the positive Z direction | ||
|spec=Mathematically equivalent to: | |spec=Mathematically equivalent to: | ||
< | <source lang="lsl2">ret = llVecNorm(<0., 0., 1.> * q);</source> | ||
If {{LSLP|q}} is known to be a unit quaternion then it can be simplified as: | If {{LSLP|q}} is known to be a unit quaternion then it can be simplified as: | ||
< | <source lang="lsl2">ret = <0., 0., 1.> * q;</source> | ||
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. | 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 | |caveats | ||
|constants | |constants | ||
|examples | |examples= | ||
<source lang="lsl2"> | |||
// 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 ); | |||
} | |||
} | |||
</source> | |||
|helpers | |helpers | ||
|also_functions= | |also_functions= | ||
| Line 23: | Line 34: | ||
|also_events | |also_events | ||
|also_articles | |also_articles | ||
|notes | |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. | ||
|permission | |permission | ||
|inventory | |inventory | ||
Latest revision as of 13:37, 22 January 2015
| LSL Portal | Functions | Events | Types | Operators | Constants | Flow Control | Script Library | Categorized Library | Tutorials |
Summary
Function: vector llRot2Up( rotation q );| 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.
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 |
Deep Notes
Signature |
|---|
function vector llRot2Up( rotation q ); |