Difference between revisions of "LlAtan2"
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(Corrected the 'compass' function.) |
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//a string with the literal compass-direction of that target towards your position | //a string with the literal compass-direction of that target towards your position | ||
//by Ramana Sweetwater 2009/01, any use allowed license :-) | //by Ramana Sweetwater 2009/01, any use allowed license :-) | ||
// I found this list of DIRS to be more accurate: | |||
// list DIRS =["SW","W","NW","N","NE","E","SE","S","SW"]; | |||
// Inanna Fairlady | |||
string compass (vector target) | string compass (vector target) | ||
Revision as of 23:07, 3 June 2010
| LSL Portal | Functions | Events | Types | Operators | Constants | Flow Control | Script Library | Categorized Library | Tutorials |
Summary
Function: float llAtan2( float y, float x );| 3 | Function ID |
| 0.0 | Forced Delay |
| 10.0 | Energy |
Returns a float that is the 
arctangent2 of y, x.
| • float | y | |||
| • float | x |
Similar to the arctangent(y/x) except it utilizes the signs of x & y to determine the quadrant. Returns zero if x and y are zero.
The returned value is in the range [-PI, PI][1].
Caveats
Examples
<lsl>default {
state_entry()
{
float num1 = llFrand(100.0);
float num2 = llFrand(100.0);
llOwnerSay("y = " + (string)num1);
llOwnerSay("x = " + (string)num2);
llOwnerSay("The arctangent of y divided by x is " + (string)llAtan2(num1, num2));
}
}</lsl><lsl>//Function with input of a vector determining the position of a target and returning //a string with the literal compass-direction of that target towards your position //by Ramana Sweetwater 2009/01, any use allowed license :-)
// I found this list of DIRS to be more accurate: // list DIRS =["SW","W","NW","N","NE","E","SE","S","SW"]; // Inanna Fairlady
string compass (vector target) {
vector me = llGetPos(); float distance = llVecDist(me, target); list DIRS =["W","NW","N","NE","E","SE","S","SW","W"]; return llList2String(DIRS,llCeil(4.5-((4*llAtan2((target.y-me.y)/distance,(target.x-me.x)/distance))/PI)));}</lsl>
See Also
Deep Notes
Footnotes
- ^ The ranges in this article are written in Interval Notation.
Signature |
|---|
function float llAtan2( float y, float x ); |