LlRot2Fwd
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Summary
Function: vector llRot2Fwd( rotation q );18 | Function ID |
0.0 | Forced Delay |
10.0 | Energy |
Computes the orientation of the local x-axis relative to the parent (i.e. the root prim or the world).
Returns a vector that is the forward vector defined by q, i.e. a unit vector pointing in the local positive X direction.
• rotation | q |
Specification
Mathematically equivalent to:
ret = llVecNorm(<1., 0., 0.> * q);
If q is known to be a unit quaternion then it can be simplified as:
ret = <1., 0., 0.> * q;
Keep in mind that object and agent rotations will always be unit quaternions. For example, <1.0, 0.0, 0.0>*llGetRot() is about 25-30% faster than llRot2Fwd(llGetRot()) depending on the VM used. If done often and at extremely fast rates, it can be advantageous to even save <1.0, 0.0, 0.0> to a local/global variable and reuse it.
Caveats
Examples
// Move an object 5 metres forwards along its x 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 = llRot2Fwd( llGetLocalRot() );
llSetPos( llGetLocalPos() + v * 5 );
}
}
Notes
Can be useful to identify the orientation of the local frontal-plane of the prim, since its x-axis is always perpendicular to this local frontal plane.
See Also
Functions
• | llRot2Left | |||
• | llRot2Up | |||
• | llRot2Axis | |||
• | llRot2Angle |