206 lines
6.7 KiB
C++
Executable file
206 lines
6.7 KiB
C++
Executable file
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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Module: FGAngles.cpp
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Author: Jon S. Berndt
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Date started: 6/2013
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------------- Copyright (C) 2013 Jon S. Berndt (jon@jsbsim.org) -------------
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This program is free software; you can redistribute it and/or modify it under
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the terms of the GNU Lesser General Public License as published by the Free Software
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Foundation; either version 2 of the License, or (at your option) any later
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version.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
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details.
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You should have received a copy of the GNU Lesser General Public License along with
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this program; if not, write to the Free Software Foundation, Inc., 59 Temple
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Place - Suite 330, Boston, MA 02111-1307, USA.
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Further information about the GNU Lesser General Public License can also be found on
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the world wide web at http://www.gnu.org.
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FUNCTIONAL DESCRIPTION
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--------------------------------------------------------------------------------
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HISTORY
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--------------------------------------------------------------------------------
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Created: 6/2013 Jon S. Berndt
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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COMMENTS, REFERENCES, and NOTES
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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The Included Angle to Heading algorithm is used to find the smallest included angle
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(the angle less than or equal to 180 degrees) to a specified heading from
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the current heading. The sense of the rotation to get to that angle is also
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calculated (positive 1 for a clockwise rotation, negative 1 for counter-
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clockwise).
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The angle to the heading is calculated as follows:
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Given an angle phi:
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V = cos(phi)i + sin(phi)j (this is a unit vector)
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The dot product for two, 2D vectors is written:
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V1*V2 = |V1||V2|cos(phi)
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Since the magnitude of a unit vector is 1, we can write the equation as follows:
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V1*V2 = cos(phi)
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or,
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phi = acos(V1*V2)
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or,
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phi = acos[ cos(phi1)cos(phi2) + sin(phi1)sin(phi2) ]
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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INCLUDES
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
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#include "FGAngles.h"
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#include "input_output/FGXMLElement.h"
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#include "input_output/FGPropertyManager.h"
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using namespace std;
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namespace JSBSim {
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IDENT(IdSrc,"$Id: FGAngles.cpp,v 1.5 2016/07/27 22:42:47 andgi Exp $");
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IDENT(IdHdr,ID_ANGLES);
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/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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CLASS IMPLEMENTATION
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
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//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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FGAngles::FGAngles(FGFCS* fcs, Element* element) : FGFCSComponent(fcs, element)
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{
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source_angle = 0.0;
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target_angle = 0.0;
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source_angle_unit = 1.0;
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target_angle_unit = 1.0;
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output_unit = 1.0;
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if (element->FindElement("target_angle") ) {
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target_angle_pNode = PropertyManager->GetNode(element->FindElementValue("target_angle"));
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if (element->FindElement("target_angle")->HasAttribute("unit")) {
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if (element->FindElement("target_angle")->GetAttributeValue("unit") == "DEG") {
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target_angle_unit = 0.017453293;
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}
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}
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} else {
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throw("Target angle is required for component: "+Name);
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}
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if (element->FindElement("source_angle") ) {
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source_angle_pNode = PropertyManager->GetNode(element->FindElementValue("source_angle"));
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if (element->FindElement("source_angle")->HasAttribute("unit")) {
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if (element->FindElement("source_angle")->GetAttributeValue("unit") == "DEG") {
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source_angle_unit = 0.017453293;
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}
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}
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} else {
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throw("Source latitude is required for Angles component: "+Name);
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}
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unit = element->GetAttributeValue("unit");
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if (!unit.empty()) {
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if (unit == "DEG") output_unit = 180.0/M_PI;
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else if (unit == "RAD") output_unit = 1.0;
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else throw("Unknown unit "+unit+" in angle component, "+Name);
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} else {
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output_unit = 1.0; // Default is radians (1.0) if unspecified
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}
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FGFCSComponent::bind();
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Debug(0);
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}
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//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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FGAngles::~FGAngles()
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{
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Debug(1);
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}
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//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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bool FGAngles::Run(void )
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{
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source_angle = source_angle_pNode->getDoubleValue() * source_angle_unit;
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target_angle = target_angle_pNode->getDoubleValue() * target_angle_unit;
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double x1 = cos(source_angle);
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double y1 = sin(source_angle);
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double x2 = cos(target_angle);
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double y2 = sin(target_angle);
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double x1x2_y1y2 = max(-1.0, min(x1*x2 + y1*y2, 1.0));
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double angle_to_heading_rad = acos(x1x2_y1y2);
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double x1y2 = x1*y2;
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double x2y1 = x2*y1;
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if (x1y2 >= x2y1) Output = angle_to_heading_rad * output_unit;
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else Output = -angle_to_heading_rad * output_unit;
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Clip();
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if (IsOutput) SetOutput();
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return true;
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}
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//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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// The bitmasked value choices are as follows:
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// unset: In this case (the default) JSBSim would only print
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// out the normally expected messages, essentially echoing
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// the config files as they are read. If the environment
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// variable is not set, debug_lvl is set to 1 internally
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// 0: This requests JSBSim not to output any messages
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// whatsoever.
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// 1: This value explicity requests the normal JSBSim
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// startup messages
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// 2: This value asks for a message to be printed out when
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// a class is instantiated
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// 4: When this value is set, a message is displayed when a
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// FGModel object executes its Run() method
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// 8: When this value is set, various runtime state variables
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// are printed out periodically
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// 16: When set various parameters are sanity checked and
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// a message is printed out when they go out of bounds
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void FGAngles::Debug(int from)
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{
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if (debug_lvl <= 0) return;
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if (debug_lvl & 1) { // Standard console startup message output
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if (from == 0) { // Constructor
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}
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}
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if (debug_lvl & 2 ) { // Instantiation/Destruction notification
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if (from == 0) cout << "Instantiated: FGAngles" << endl;
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if (from == 1) cout << "Destroyed: FGAngles" << endl;
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}
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if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
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}
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if (debug_lvl & 8 ) { // Runtime state variables
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}
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if (debug_lvl & 16) { // Sanity checking
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}
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if (debug_lvl & 64) {
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if (from == 0) { // Constructor
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cout << IdSrc << endl;
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cout << IdHdr << endl;
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}
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}
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}
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}
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