Difference between revisions of "LlAngleBetween"
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{{Issues/SVC-2424}} | {{LSL_Function | ||
|inject-2={{Issues/SVC-2424}} | |||
|func_id=174|func_sleep=0.0|func_energy=10.0 | |func_id=174|func_sleep=0.0|func_energy=10.0 | ||
|func=llAngleBetween|sort=AngleBetween | |func=llAngleBetween|sort=AngleBetween | ||
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|p2_type=rotation|p2_name=b|p2_desc=end rotation | |p2_type=rotation|p2_name=b|p2_desc=end rotation | ||
|func_footnote | |func_footnote | ||
|return_text=that is the angle between rotation | |return_text=that is the angle between rotation {{LSLP|a}} and {{LSLP|b}}. | ||
|spec | |spec | ||
|caveats | |caveats | ||
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|also_articles | |also_articles | ||
|notes | |notes | ||
|deepnotes=<lsl>float AngleBetween(rotation a, rotation b) | |deepnotes= ===Reference=== | ||
<lsl>float AngleBetween(rotation a, rotation b)//simple but turns out to not be very accurate. | |||
{ | { | ||
return 2.0 * llAcos((a.x * b.x + a.y * b.y + a.z * b.z + a.s * b.s) | return 2.0 * llAcos((a.x * b.x + a.y * b.y + a.z * b.z + a.s * b.s) | ||
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* (b.x * b.x + b.y * b.y + b.z * b.z + b.s * b.s))); | * (b.x * b.x + b.y * b.y + b.z * b.z + b.s * b.s))); | ||
}</lsl> | }</lsl> | ||
<lsl>float AngleBetween(rotation a, rotation b)//more complex implementation but very accurate, and reasonably fast. | |||
{ | |||
rotation r = b / a; // calculate the rotation between the two arguments as quaternion | |||
float s2 = r.s * r.s; // square of the s-element | |||
float v2 = r.x * r.x + r.y * r.y + r.z * r.z; // sum of the squares of the v-elements | |||
if (s2 < v2) // compare the s-component to the v-component | |||
return 2 * llAcos(llSqrt(s2 / (s2 + v2))); // use arccos if the v-component is dominant | |||
else if (v2) | |||
return 2 * llAsin(llSqrt(v2 / (s2 + v2))); // use arcsin if the s-component is dominant | |||
return 0; // one or both arguments are scaled too small to be meaningful, or the values are the same, so return zero | |||
}//Written by Moon Metty, Miranda Umino. Minor optimizations by Strife Onizuka</lsl> | |||
Watch for developments on this function with {{Jira|SVC-2424}} | |||
|cat1=Math/3D | |cat1=Math/3D | ||
|cat2 | |cat2 | ||
Revision as of 09:25, 2 September 2012
| LSL Portal | Functions | Events | Types | Operators | Constants | Flow Control | Script Library | Categorized Library | Tutorials |
Summary
Function: float llAngleBetween( rotation a, rotation b );| 174 | Function ID |
| 0.0 | Forced Delay |
| 10.0 | Energy |
Returns a float that is the angle between rotation a and b.
| • rotation | a | – | start rotation | |
| • rotation | b | – | end rotation |
Caveats
Important Issues
~ All Issues ~ Search JIRA for related Bugs
|
|
SVC-2424 | A | llAngleBetween() is sometimes inaccurate |
Examples
See Also
Functions
| • | llRotBetween | |||
| • | llRot2Angle | – | Similar functionality used for the Axis-Angle format |
Deep Notes
Reference
<lsl>float AngleBetween(rotation a, rotation b)//simple but turns out to not be very accurate. {
return 2.0 * llAcos((a.x * b.x + a.y * b.y + a.z * b.z + a.s * b.s)
/ llSqrt((a.x * a.x + a.y * a.y + a.z * a.z + a.s * a.s)
* (b.x * b.x + b.y * b.y + b.z * b.z + b.s * b.s)));
}</lsl>
<lsl>float AngleBetween(rotation a, rotation b)//more complex implementation but very accurate, and reasonably fast. {
rotation r = b / a; // calculate the rotation between the two arguments as quaternion float s2 = r.s * r.s; // square of the s-element float v2 = r.x * r.x + r.y * r.y + r.z * r.z; // sum of the squares of the v-elements
if (s2 < v2) // compare the s-component to the v-component
return 2 * llAcos(llSqrt(s2 / (s2 + v2))); // use arccos if the v-component is dominant
else if (v2)
return 2 * llAsin(llSqrt(v2 / (s2 + v2))); // use arcsin if the s-component is dominant
return 0; // one or both arguments are scaled too small to be meaningful, or the values are the same, so return zero
}//Written by Moon Metty, Miranda Umino. Minor optimizations by Strife Onizuka</lsl>
Watch for developments on this function with SVC-2424
All Issues
~ Search JIRA for related Issues|
|
|
SVC-2424 | A | llAngleBetween() is sometimes inaccurate |
Signature |
|---|
function float llAngleBetween( rotation a, rotation b ); |