Difference between revisions of "LlRotBetween"
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m (Noted bug in llRotBetween and added caveat that the rotations returned range from -PI to +PI around each axis.) |
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|spec='''start''' and '''end''' are directions and are relative to the origin <0.0, 0.0, 0.0>. If you have coordinates relative to a different origin, subtract that origin from the input vectors. | |spec='''start''' and '''end''' are directions and are relative to the origin <0.0, 0.0, 0.0>. If you have coordinates relative to a different origin, subtract that origin from the input vectors. | ||
|caveats=*<code>start * llRotBetween(start, end) == end</code> is only true if '''start''' and '''end''' have the same magnitude and neither have a magnitude of zero (see [[#Notes]] for a workaround). | |caveats=*<code>start * llRotBetween(start, end) == end</code> is only true if '''start''' and '''end''' have the same magnitude and neither have a magnitude of zero (see [[#Notes]] for a workaround). | ||
* Rotations are from -PI to +PI around each axis. | |||
|constants | |constants | ||
|examples= | |examples= | ||
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return rot; | return rot; | ||
}//Strife Onizuka</lsl> | }//Strife Onizuka</lsl> | ||
Vectors that are near opposite each other in direction may lead to erroneous results. | |||
<lsl> | |||
// First Vector is due north second vector is ALMOST due south. | |||
rotation lRotation = llRotBetween( <0., 1., 0.>, <-0.001, -.1, 0.> ); | |||
llSay(0, lRotation ); | |||
// Provides a result of <1.00000, 0.00000, 0.00000, 0.00000>. | |||
</lsl> | |||
|deprecated | |deprecated | ||
|cat1=Math/3D | |cat1=Math/3D | ||
Revision as of 11:44, 20 June 2009
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Summary
Function: rotation llRotBetween( vector start, vector end );| 21 | Function ID |
| 0.0 | Forced Delay |
| 10.0 | Energy |
Returns a rotation that is the rotation between the direction start and the direction end
| • vector | start | |||
| • vector | end |
Specification
start and end are directions and are relative to the origin <0.0, 0.0, 0.0>. If you have coordinates relative to a different origin, subtract that origin from the input vectors.
Caveats
start * llRotBetween(start, end) == endis only true if start and end have the same magnitude and neither have a magnitude of zero (see #Notes for a workaround).- Rotations are from -PI to +PI around each axis.
Examples
<lsl>llRotBetween(<1.0, 0.0, 0.0>, <0.0, -1.0, 0.0>) // will return <0.00000, 0.00000, -0.70711, 0.70711> (which represents -45 degrees on the z axis)
llRotBetween(<0.0, 0.0, 0.0>, <0.0, -1.0, 0.0>) // will return <0.00000, 0.00000, 0.00000, 1.00000> (which represents a zero angle on all axis)
// because <0.0, 0.0, 0.0> does not convey a direction.</lsl>Notes
This function adjusts the magnitude of the quaternion so start * llRotBetween(start, end) == end is true as long as neither have a magnitude of zero. They don't have to have the same magnitude.
<lsl>rotation RotBetween(vector start, vector end) //adjusts quaternion magnitude so (start * return == end)
{//Authors note: I have never had a use for this but it's good to know how to do it if I did.
rotation rot = llRotBetween(start, end);
if(start)
{
if(end)
{
float d = llSqrt(llVecMag(end) / llVecMag(start));
return <rot.x * d, rot.y * d, rot.z * d, rot.s * d>;
}
}
return rot;
}//Strife Onizuka</lsl> Vectors that are near opposite each other in direction may lead to erroneous results. <lsl> // First Vector is due north second vector is ALMOST due south. rotation lRotation = llRotBetween( <0., 1., 0.>, <-0.001, -.1, 0.> ); llSay(0, lRotation ); // Provides a result of <1.00000, 0.00000, 0.00000, 0.00000>. </lsl>
See Also
Functions
| • | llAngleBetween |
Deep Notes
Search JIRA for related Issues
Signature |
|---|
function rotation llRotBetween( vector start, vector end ); |