Difference between revisions of "LlRot2Fwd"

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|func=llRot2Fwd|sort=Rot2Fwd
 
|func=llRot2Fwd|sort=Rot2Fwd
 
|return_type=vector|p1_type=rotation|p1_name=q
 
|return_type=vector|p1_type=rotation|p1_name=q
|func_footnote
+
|func_desc=Computes the orientation of the {{HoverText|local x-axis|front-direction of prim}} relative to the parent (i.e. the root prim or the world).
|func_desc
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|return_text=that is the forward vector defined by {{LSLP|q}}, i.e. a unit vector pointing in the local positive X direction.
|return_text=that is the forward vector defined by '''q''', i.e. a unit vector pointing in the local positive X direction.
+
|spec=Mathematically equivalent to:
|spec
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<source lang="lsl2">ret = llVecNorm(<1., 0., 0.> * q);</source>
 +
If {{LSLP|q}} is known to be a unit quaternion then it can be simplified as:
 +
<source lang="lsl2">ret = <1., 0., 0.> * q;</source>
 +
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
 
|caveats
 
|constants
 
|constants
|examples
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|examples=
 +
<source lang="lsl2">
 +
// 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 );
 +
    }
 +
}
 +
</source>
 
|helpers
 
|helpers
|also_functions=*{{LSLG|llRot2Left}}
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|also_functions=
*{{LSLG|llRot2Up}}
+
{{LSL DefineRow||[[llRot2Left]]}}
*{{LSLG|llRot2Axis}}
+
{{LSL DefineRow||[[llRot2Up]]}}
*{{LSLG|llRot2Angle}}
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{{LSL DefineRow||[[llRot2Axis]]}}
 +
{{LSL DefineRow||[[llRot2Angle]]}}
 
|also_tests
 
|also_tests
 
|also_events
 
|also_events
 
|also_articles
 
|also_articles
|notes
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|notes=Can be useful to identify the orientation of the local {{HoverText|frontal-plane|coronal-plane}} of the prim, since its x-axis is always perpendicular to this local frontal plane.
|permission
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|inventory
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|negative_index
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|cat1=Rotation
 
|cat1=Rotation
 
|cat2
 
|cat2

Latest revision as of 14:35, 22 January 2015

Summary

Function: vector llRot2Fwd( rotation q );

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.

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

Deep Notes

Search JIRA for related Issues

Signature

function vector llRot2Fwd( rotation q );