git.gag.com Git - sw/motorsim/blob - src/com/billkuker/rocketry/motorsim/grain/BurningShape.java

   1 package com.billkuker.rocketry.motorsim.grain;\r
   2 \r
   3 import java.awt.Shape;\r
   4 import java.awt.geom.Area;\r
   5 import java.awt.geom.Ellipse2D;\r
   6 import java.awt.geom.Rectangle2D;\r
   7 import java.awt.geom.RoundRectangle2D;\r
   8 import java.util.HashSet;\r
   9 import java.util.Set;\r
  10 \r
  11 import javax.measure.quantity.Length;\r
  12 import javax.measure.unit.SI;\r
  13 \r
  14 import org.jscience.physics.amount.Amount;\r
  15 \r
  16 public class BurningShape {\r
  17         Set<Shape> plus = new HashSet<Shape>();\r
  18         Set<Shape> minus = new HashSet<Shape>();\r
  19         Set<Shape> inhibited = new HashSet<Shape>();\r
  20         \r
  21         public void add(Shape s){\r
  22                 plus.add(s);\r
  23         }\r
  24         \r
  25         public void subtract(Shape s){\r
  26                 minus.add(s);\r
  27         }\r
  28         \r
  29         public void inhibit(Shape s){\r
  30                 inhibited.add(s);\r
  31         }\r
  32 \r
  33         /*\r
  34          * 9 times out of 10 we get asked for the same thing\r
  35          * 2x in a row, for volume and for area\r
  36          */\r
  37         private Amount<Length> lastRegression = null;\r
  38         private Area lastArea = null;\r
  39         \r
  40         public java.awt.geom.Area getShape(Amount<Length> regression) {\r
  41                 if ( regression.equals(lastRegression) ){\r
  42                         return lastArea;\r
  43                 }\r
  44                 lastRegression = regression;\r
  45 \r
  46                 java.awt.geom.Area a = new java.awt.geom.Area();\r
  47                 for (Shape s : plus)\r
  48                         a.add(new java.awt.geom.Area(regress(s, regression\r
  49                                         .doubleValue(SI.MILLIMETER), true)));\r
  50                 for (Shape s : minus)\r
  51                         a.subtract(new java.awt.geom.Area(regress(s, regression\r
  52                                         .doubleValue(SI.MILLIMETER), false)));\r
  53                 \r
  54                 return lastArea = a;\r
  55         }\r
  56         \r
  57         private Shape regress(Shape s, double mm, boolean plus) {\r
  58                 if (inhibited.contains(s))\r
  59                         return s;\r
  60                 if (s instanceof Ellipse2D) {\r
  61                         Ellipse2D e = (Ellipse2D) s;\r
  62 \r
  63                         double d = plus ? -2 * mm : 2 * mm;\r
  64 \r
  65                         double w = e.getWidth() + d;\r
  66                         double h = e.getHeight() + d;\r
  67                         double x = e.getX() - d / 2;\r
  68                         double y = e.getY() - d / 2;\r
  69 \r
  70                         return new Ellipse2D.Double(x, y, w, h);\r
  71                 } else if (s instanceof Rectangle2D) {\r
  72                         Rectangle2D r = (Rectangle2D) s;\r
  73                         \r
  74                         if ( plus ){\r
  75                                 double d = -2 * mm;\r
  76                                 double w = r.getWidth() + d;\r
  77                                 double h = r.getHeight() + d;\r
  78                                 double x = r.getX() - d / 2;\r
  79                                 double y = r.getY() - d / 2;\r
  80                                 return new Rectangle2D.Double(x, y, w, h);\r
  81                         } else {\r
  82                                 //A rectangular hole gets rounded corners as it grows\r
  83                                 java.awt.geom.Area a = new java.awt.geom.Area();\r
  84                                 double d = 2 * mm;\r
  85                                 \r
  86                                 a.add(new Area(new RoundRectangle2D.Double(\r
  87                                                 r.getX() - d / 2,\r
  88                                                 r.getY() - d / 2,\r
  89                                                 r.getWidth() + d,\r
  90                                                 r.getHeight() + d,\r
  91                                                 d,\r
  92                                                 d\r
  93                                                 )));\r
  94 \r
  95                                 return a;\r
  96                         }\r
  97 \r
  98                 }\r
  99                 return null;\r
 100         }\r
 101 \r
 102         \r
 103 }\r