git.gag.com Git - debian/openrocket/blob - src/net/sf/openrocket/rocketcomponent/TrapezoidFinSet.java

   1 package net.sf.openrocket.rocketcomponent;
   2
   3 import net.sf.openrocket.util.Coordinate;
   4
   5 /**
   6  * A set of trapezoidal fins.  The root and tip chords are perpendicular to the rocket
   7  * base line, while the leading and aft edges may be slanted.
   8  *
   9  * @author Sampo Niskanen <sampo.niskanen@iki.fi>
  10  */
  11
  12 public class TrapezoidFinSet extends FinSet {
  13         public static final double MAX_SWEEP_ANGLE=(89*Math.PI/180.0);
  14
  15         /*
  16          *           sweep   tipChord
  17          *           |    |___________
  18          *           |   /            |
  19          *           |  /             |
  20          *           | /              |  height
  21          *            /               |
  22          * __________/________________|_____________
  23          *                length
  24          *              == rootChord
  25          */
  26
  27         // rootChord == length
  28         private double tipChord = 0;
  29         private double height = 0;
  30         private double sweep = 0;
  31
  32
  33         public TrapezoidFinSet() {
  34                 this (3, 0.05, 0.05, 0.025, 0.05);
  35         }
  36
  37         // TODO: HIGH:  height=0 -> CP = NaN
  38         public TrapezoidFinSet(int fins, double rootChord, double tipChord, double sweep,
  39                         double height) {
  40                 super();
  41
  42                 this.setFinCount(fins);
  43                 this.length = rootChord;
  44                 this.tipChord = tipChord;
  45                 this.sweep = sweep;
  46                 this.height = height;
  47         }
  48
  49
  50         public void setFinShape(double rootChord, double tipChord, double sweep, double height,
  51                         double thickness) {
  52                 if (this.length==rootChord && this.tipChord==tipChord && this.sweep==sweep &&
  53                                 this.height==height && this.thickness==thickness)
  54                         return;
  55                 this.length=rootChord;
  56                 this.tipChord=tipChord;
  57                 this.sweep=sweep;
  58                 this.height=height;
  59                 this.thickness=thickness;
  60                 fireComponentChangeEvent(ComponentChangeEvent.BOTH_CHANGE);
  61         }
  62
  63         public double getRootChord() {
  64                 return length;
  65         }
  66         public void setRootChord(double r) {
  67                 if (length == r)
  68                         return;
  69                 length = Math.max(r,0);
  70                 fireComponentChangeEvent(ComponentChangeEvent.BOTH_CHANGE);
  71         }
  72
  73         public double getTipChord() {
  74                 return tipChord;
  75         }
  76         public void setTipChord(double r) {
  77                 if (tipChord == r)
  78                         return;
  79                 tipChord = Math.max(r,0);
  80                 fireComponentChangeEvent(ComponentChangeEvent.BOTH_CHANGE);
  81         }
  82
  83         /**
  84          * Get the sweep length.
  85          */
  86         public double getSweep() {
  87                 return sweep;
  88         }
  89         /**
  90          * Set the sweep length.
  91          */
  92         public void setSweep(double r) {
  93                 if (sweep == r)
  94                         return;
  95                 sweep = r;
  96                 fireComponentChangeEvent(ComponentChangeEvent.BOTH_CHANGE);
  97         }
  98
  99         /**
 100          * Get the sweep angle.  This is calculated from the true sweep and height, and is not
 101          * stored separetely.
 102          */
 103         public double getSweepAngle() {
 104                 if (height == 0) {
 105                         if (sweep > 0)
 106                                 return Math.PI/2;
 107                         if (sweep < 0)
 108                                 return -Math.PI/2;
 109                         return 0;
 110                 }
 111                 return Math.atan(sweep/height);
 112         }
 113         /**
 114          * Sets the sweep by the sweep angle.  The sweep is calculated and set by this method,
 115          * and the angle itself is not stored.
 116          */
 117         public void setSweepAngle(double r) {
 118                 if (r > MAX_SWEEP_ANGLE)
 119                         r = MAX_SWEEP_ANGLE;
 120                 if (r < -MAX_SWEEP_ANGLE)
 121                         r = -MAX_SWEEP_ANGLE;
 122                 double sweep = Math.tan(r) * height;
 123                 if (Double.isNaN(sweep) || Double.isInfinite(sweep))
 124                         return;
 125                 setSweep(sweep);
 126         }
 127
 128         public double getHeight() {
 129                 return height;
 130         }
 131         public void setHeight(double r) {
 132                 if (height == r)
 133                         return;
 134                 height = Math.max(r,0);
 135                 fireComponentChangeEvent(ComponentChangeEvent.BOTH_CHANGE);
 136         }
 137
 138
 139
 140         /**
 141          * Returns the geometry of a trapezoidal fin.
 142          */
 143         @Override
 144         public Coordinate[] getFinPoints() {
 145                 Coordinate[] c = new Coordinate[4];
 146
 147                 c[0] = Coordinate.NUL;
 148                 c[1] = new Coordinate(sweep,height);
 149                 c[2] = new Coordinate(sweep+tipChord,height);
 150                 c[3] = new Coordinate(length,0);
 151
 152                 return c;
 153         }
 154
 155         /**
 156          * Returns the span of a trapezoidal fin.
 157          */
 158         @Override
 159         public double getSpan() {
 160                 return height;
 161         }
 162
 163
 164         @Override
 165         public String getComponentName() {
 166                 return "Trapezoidal fin set";
 167         }
 168
 169 }