ACE3/addons/advanced_ballistics/functions/fnc_calculateWindSpeed.sqf

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/*
* Author: Ruthberg
*
* Calculates the true wind speed at a given world position
*
* Arguments:
* 0: _this - world position <posASL>
*
* Return Value:
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* 0: wind speed - m/s <NUMBER>
*
* Public: No
*/
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#include "script_component.hpp"
private ["_windSpeed", "_windDir", "_height", "_newWindSpeed", "_windSource", "_roughnessLength"];
fnc_polar2vect = {
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private ["_mag2D"];
_mag2D = (_this select 0) * cos((_this select 2));
[_mag2D * sin((_this select 1)), _mag2D * cos((_this select 1)), (_this select 0) * sin((_this select 2))];
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};
_windSpeed = vectorMagnitude ACE_wind;
_windDir = (ACE_wind select 0) atan2 (ACE_wind select 1);
// Wind gradient
if (_windSpeed > 0.05) then {
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_height = (ASLToATL _this) select 2;
_height = 0 max _height min 20;
if (_height < 20) then {
_roughnessLength = _this call FUNC(calculateRoughnessLength);
_windSpeed = _windSpeed * ln(_height / _roughnessLength) / ln(20 / _roughnessLength);
};
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};
// Terrain effect on wind
if (_windSpeed > 0.05) then {
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_newWindSpeed = 0;
{
_windSource = [100, _windDir + 180, _x] call fnc_polar2vect;
if (!(terrainIntersectASL [_this, _this vectorAdd _windSource])) exitWith {
_newWindSpeed = cos(_x * 9) * _windSpeed;
};
_windSource = [100, _windDir + 180 + _x, 0] call fnc_polar2vect;
if (!(terrainIntersectASL [_this, _this vectorAdd _windSource])) exitWith {
_newWindSpeed = cos(_x * 9) * _windSpeed;
};
_windSource = [100, _windDir + 180 - _x, 0] call fnc_polar2vect;
if (!(terrainIntersectASL [_this, _this vectorAdd _windSource])) exitWith {
_newWindSpeed = cos(_x * 9) * _windSpeed;
};
} forEach [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
_windSpeed = _newWindSpeed;
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};
// Obstacle effect on wind
if (_windSpeed > 0.05) then {
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_newWindSpeed = 0;
{
_windSource = [20, _windDir + 180, _x] call fnc_polar2vect;
if (!(lineIntersects [_this, _this vectorAdd _windSource])) exitWith {
_newWindSpeed = cos(_x * 2) * _windSpeed;
};
_windSource = [20, _windDir + 180 + _x, 0] call fnc_polar2vect;
if (!(lineIntersects [_this, _this vectorAdd _windSource])) exitWith {
_newWindSpeed = cos(_x * 2) * _windSpeed;
};
_windSource = [20, _windDir + 180 - _x, 0] call fnc_polar2vect;
if (!(lineIntersects [_this, _this vectorAdd _windSource])) exitWith {
_newWindSpeed = cos(_x * 2) * _windSpeed;
};
} forEach [0, 5, 10, 15, 20, 25, 30, 35, 40, 45];
_windSpeed = _newWindSpeed;
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};
_windSpeed = 0 max _windSpeed;
_windSpeed