Difference between revisions of "LlVecDist"

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Revision as of 13:23, 4 April 2014

Summary

Function: float llVecDist( vector vec_a, vector vec_b );

Returns a float that is the undirected nonnegative distance between vec_a and vec_b.

• vector vec_a Any valid vector
• vector vec_b Any valid vector

Examples

<lsl> default {

   state_entry()
   {
       vector input_1 = <1.0,2.0,3.0>;
       vector input_2 = <3.0,2.0,1.0>;
       llOwnerSay("The distance between " + (string) input_1 +
           " and " + (string) input_2 + " is: "+(string)llVecDist(input_1, input_2) );
   }

} </lsl> <lsl> //To reset script on touch if the object has been rotated since the last script reset float gTolerance = 0.05; //This corresponds to about a 3 degree rotation default { state_entry() { llSetObjectDesc((string)llRot2Euler(llGetRot())); }

touch_start(integer total_number) { if (llVecDist(llRot2Euler(llGetRot()), (vector)llGetObjectDesc()) > gTolerance) { llSay(0,"This object has rotated. Automatic reset engaged."); llResetScript(); } } }</lsl>

Video Tutorial

Notes

  • Mathematically equivalent to:
    • llVecMag( vec_a - vec_b )
    • llSqrt( (vec_b.x - vec_a.x) * (vec_b.x - vec_a.x) + (vec_b.y - vec_a.y) * (vec_b.y - vec_a.y) + (vec_b.z - vec_a.z) * (vec_b.z - vec_a.z) )
  • Knowing this, there are ways to circumvent llVecDist for more efficient code.
    • For example, vector v3 = (v1-v2); v3*v3 < (f*f); is over twice as fast as llVecDist(v1,v2) < f;

See Also

Functions

•  llVecMag
•  llVecNorm

Deep Notes

Search JIRA for related Issues

Signature

function float llVecDist( vector vec_a, vector vec_b );

Haiku

Squirrel on a wire,
Skips from pole to distant pole.
One leap at a time.