ACE3/addons/weather/functions/fnc_calculateWindSpeed.sqf

93 lines
3.2 KiB
Plaintext
Raw Normal View History

/*
* Author: Ruthberg
*
* Calculates the true wind speed at a given world position
*
* Arguments:
* 0: world position - posASL <POSTION>
* 1: Account for wind gradient <BOOL>
* 2: Account for terrain <BOOL>
* 3: Account for obstacles <BOOL>
*
* Return Value:
* wind speed - m/s <NUMBER>
*
* Public: No
*/
#include "script_component.hpp"
private ["_fnc_polar2vect", "_windSpeed", "_windDir", "_windDirAdjusted", "_height", "_newWindSpeed", "_windSource", "_roughnessLength"];
params ["_position", "_windGradientEnabled", "_terrainEffectEnabled", "_obstacleEffectEnabled"];
_fnc_polar2vect = {
private ["_mag2D"];
params ["_x", "_y", "_z"];
_mag2D = _x * cos(_z);
[_mag2D * sin(_y), _mag2D * cos(_y), _x * sin(_z)];
};
_windSpeed = vectorMagnitude ACE_wind;
_windDir = (ACE_wind select 0) atan2 (ACE_wind select 1);
_windDirAdjusted = _windDir + 180;
// Wind gradient
if (_windGradientEnabled) then {
if (_windSpeed > 0.05) then {
_height = (ASLToATL _position) select 2;
_height = 0 max _height min 20;
if (_height < 20) then {
_roughnessLength = _position call FUNC(calculateRoughnessLength);
_windSpeed = _windSpeed * abs(ln(_height / _roughnessLength) / ln(20 / _roughnessLength));
};
};
};
// Terrain effect on wind
if (_terrainEffectEnabled) then {
if (_windSpeed > 0.05) then {
_newWindSpeed = 0;
{
_windSource = [100, _windDirAdjusted, _x] call _fnc_polar2vect;
if (!(terrainIntersectASL [_position, _position vectorAdd _windSource])) exitWith {
_newWindSpeed = cos(_x * 9) * _windSpeed;
};
_windSource = [100, _windDirAdjusted + _x, 0] call _fnc_polar2vect;
if (!(terrainIntersectASL [_position, _position vectorAdd _windSource])) exitWith {
_newWindSpeed = cos(_x * 9) * _windSpeed;
};
_windSource = [100, _windDirAdjusted - _x, 0] call _fnc_polar2vect;
if (!(terrainIntersectASL [_position, _position vectorAdd _windSource])) exitWith {
_newWindSpeed = cos(_x * 9) * _windSpeed;
};
} count [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
_windSpeed = _newWindSpeed;
};
};
// Obstacle effect on wind
if (_obstacleEffectEnabled) then {
if (_windSpeed > 0.05) then {
_newWindSpeed = 0;
{
_windSource = [20, _windDirAdjusted, _x] call _fnc_polar2vect;
if (!(lineIntersects [_position, _position vectorAdd _windSource])) exitWith {
_newWindSpeed = cos(_x * 2) * _windSpeed;
};
_windSource = [20, _windDirAdjusted + _x, 0] call _fnc_polar2vect;
if (!(lineIntersects [_position, _position vectorAdd _windSource])) exitWith {
_newWindSpeed = cos(_x * 2) * _windSpeed;
};
_windSource = [20, _windDirAdjusted - _x, 0] call _fnc_polar2vect;
if (!(lineIntersects [_position, _position vectorAdd _windSource])) exitWith {
_newWindSpeed = cos(_x * 2) * _windSpeed;
};
} count [0, 5, 10, 15, 20, 25, 30, 35, 40, 45];
_windSpeed = _newWindSpeed;
};
};
_windSpeed = 0 max _windSpeed;
_windSpeed