Initial commit

[debian/openrocket] / src / net / sf / openrocket / aerodynamics / AtmosphericModel.java

diff --git a/src/net/sf/openrocket/aerodynamics/AtmosphericModel.java b/src/net/sf/openrocket/aerodynamics/AtmosphericModel.java
new file mode 100644 (file)
index 0000000..ea2ead0
--- /dev/null
+++ b/src/net/sf/openrocket/aerodynamics/AtmosphericModel.java
@@ -0,0 +1,41 @@
+package net.sf.openrocket.aerodynamics;
+
+public abstract class AtmosphericModel {
+       /** Layer thickness of interpolated altitude. */
+       private static final double DELTA = 500;
+       
+       private AtmosphericConditions[] levels = null;
+       
+       
+       public AtmosphericConditions getConditions(double altitude) {
+               if (levels == null)
+                       computeLayers();
+               
+               if (altitude <= 0)
+                       return levels[0];
+               if (altitude >= DELTA*(levels.length-1))
+                       return levels[levels.length-1];
+               
+               int n = (int)(altitude/DELTA);
+               double d = (altitude - n*DELTA)/DELTA;
+               AtmosphericConditions c = new AtmosphericConditions();
+               c.temperature = levels[n].temperature * (1-d) + levels[n+1].temperature * d;
+               c.pressure = levels[n].pressure * (1-d) + levels[n+1].pressure * d;
+                       
+               return c;
+       }
+       
+       
+       private void computeLayers() {
+               double max = getMaxAltitude();
+               int n = (int)(max/DELTA) + 1;
+               levels = new AtmosphericConditions[n];
+               for (int i=0; i < n; i++) {
+                       levels[i] = getExactConditions(i*DELTA);
+               }
+       }
+
+       
+       public abstract double getMaxAltitude();
+       public abstract AtmosphericConditions getExactConditions(double altitude);
+}