[#1315] Update auto length in MassObject

core/src/net/sf/openrocket/file/openrocket/savers/MassObjectSaver.java

@@ -13,7 +13,7 @@ public class MassObjectSaver extends InternalComponentSaver {
 
 		MassObject mass = (MassObject) c;
 
-		elements.add("<packedlength>" + mass.getLength() + "</packedlength>");
+		elements.add("<packedlength>" + mass.getLengthNoAuto() + "</packedlength>");
 		if (mass.isRadiusAutomatic()) {
 			elements.add("<packedradius>auto " + mass.getRadiusNoAuto() + "</packedradius>");
 		} else {

core/src/net/sf/openrocket/file/rocksim/export/BasePartDTO.java

@@ -12,6 +12,7 @@ import net.sf.openrocket.file.rocksim.RocksimLocationMode;
 import net.sf.openrocket.file.rocksim.importt.BaseHandler;
 import net.sf.openrocket.rocketcomponent.ExternalComponent;
 import net.sf.openrocket.rocketcomponent.FinSet;
+import net.sf.openrocket.rocketcomponent.MassObject;
 import net.sf.openrocket.rocketcomponent.RecoveryDevice;
 import net.sf.openrocket.rocketcomponent.RingComponent;
 import net.sf.openrocket.rocketcomponent.RocketComponent;
@@ -83,7 +84,7 @@ public abstract class BasePartDTO {
         setKnownCG(ec.getOverrideCGX() * RocksimCommonConstants.ROCKSIM_TO_OPENROCKET_LENGTH);
         setKnownMass(ec.getMass() * RocksimCommonConstants.ROCKSIM_TO_OPENROCKET_MASS);
 
-        if (! (ec instanceof FinSet)) {
+        if (!(ec instanceof FinSet || ec instanceof MassObject)) {
             setLen(ec.getLength() * RocksimCommonConstants.ROCKSIM_TO_OPENROCKET_LENGTH);
         }
         setUseKnownCG(ec.isCGOverridden() || ec.isMassOverridden() ? 1 : 0);
@@ -146,6 +147,10 @@ public abstract class BasePartDTO {
             setRadialAngle(rc.getRadialDirection());
             setRadialLoc(rc.getRadialPosition() * RocksimCommonConstants.ROCKSIM_TO_OPENROCKET_LENGTH);
         }
+
+        if (ec instanceof MassObject) {
+            setLen(((MassObject)ec).getLengthNoAuto() * RocksimCommonConstants.ROCKSIM_TO_OPENROCKET_LENGTH);
+        }
     }
 
     public Double getKnownMass() {

core/src/net/sf/openrocket/rocketcomponent/MassObject.java

@@ -50,7 +50,21 @@ public abstract class MassObject extends InternalComponent {
 		return false;
 	}
 
-	
+	@Override
+	public double getLength() {
+		if (this.autoRadius) {
+			// Calculate the parachute volume using the non auto radius and the non auto length, and transform that back
+			// to the auto radius situation to get the auto radius length (the volume in both situations is the same).
+			double parachuteVolume = Math.pow(this.radius, 2) * this.length;	// Math.PI left out, not needed
+			return parachuteVolume / Math.pow(getRadius(), 2);
+		}
+		return length;
+	}
+
+	public double getLengthNoAuto() {
+		return length;
+	}
+
 	public void setLength(double length) {
 		for (RocketComponent listener : configListeners) {
 			if (listener instanceof MassObject) {
@@ -59,10 +73,17 @@ public abstract class MassObject extends InternalComponent {
 		}
 
 		length = Math.max(length, 0);
-		if (MathUtil.equals(this.length, length)) {
+		if (this.autoRadius) {
-			return;
+			// Calculate the parachute volume using the auto radius and the new "auto" length, and transform that back
+			// to the non auto radius situation to set this.length (the volume in both situations is the same).
+			double parachuteVolume = Math.pow(getRadius(), 2) * length;		// Math.PI left out, not needed
+			this.length = parachuteVolume / Math.pow(this.radius, 2);
+		} else {
+			if (MathUtil.equals(this.length, length)) {
+				return;
+			}
+			this.length = length;
 		}
-		this.length = length;
 		fireComponentChangeEvent(ComponentChangeEvent.MASS_CHANGE);
 	}
 	
@@ -114,8 +135,8 @@ public abstract class MassObject extends InternalComponent {
 
 	public void setRadiusAutomatic(boolean auto) {
 		for (RocketComponent listener : configListeners) {
-			if (listener instanceof Parachute) {
+			if (listener instanceof MassObject) {
-				((Parachute) listener).setRadiusAutomatic(auto);
+				((MassObject) listener).setRadiusAutomatic(auto);
 			}
 		}
 
@@ -124,6 +145,10 @@ public abstract class MassObject extends InternalComponent {
 
 		autoRadius = auto;
 
+		// Set the length
+		double parachuteVolume = (Math.PI * Math.pow(getRadius(), 2) * length);
+		length = parachuteVolume / (Math.PI * Math.pow(getRadius(), 2));
+
 		fireComponentChangeEvent(ComponentChangeEvent.BOTH_CHANGE);
 	}
 	

core/src/net/sf/openrocket/rocketcomponent/Parachute.java

@@ -18,8 +18,6 @@ public class Parachute extends RecoveryDevice {
 	private int lineCount;
 	private final double DEFAULT_LINE_LENGTH = 0.3;
 	private double lineLength;
-	private final double InitialPackedLength = this.length;
-	private final double InitialPackedRadius = this.radius;
 
 	public Parachute() {
 		this.diameter = DEFAULT_DIAMETER;
@@ -213,23 +211,15 @@ public class Parachute extends RecoveryDevice {
 
 		//	//	Set preset parachute packed length
 		if ((preset.has(ComponentPreset.PACKED_LENGTH)) && preset.get(ComponentPreset.PACKED_LENGTH) > 0) {
-			this.PackedLength = preset.get(ComponentPreset.PACKED_LENGTH);
+			length = preset.get(ComponentPreset.PACKED_LENGTH);
-			length = PackedLength;
-		} else {
-			length = InitialPackedLength;
 		}
 		//	// Set preset parachute packed diameter
 		if ((preset.has(ComponentPreset.PACKED_DIAMETER)) && preset.get(ComponentPreset.PACKED_DIAMETER) > 0) {
-			this.PackedDiameter = preset.get(ComponentPreset.PACKED_DIAMETER);
+			radius = preset.get(ComponentPreset.PACKED_DIAMETER) / 2;
-			radius = PackedDiameter / 2;
-		} else {
-			radius = InitialPackedRadius;
 		}
 		//	// Size parachute packed diameter within parent inner diameter
 		if (length > 0 && radius > 0) {
-			double parachuteVolume = (Math.PI * Math.pow(radius, 2) * length);
 			setRadiusAutomatic(true);
-			length = parachuteVolume / (Math.PI * Math.pow(getRadius(), 2));
 		}
 
 		// SUBSTITUTE / ACTIVATE Override Mass Preset

core/src/net/sf/openrocket/rocketcomponent/RecoveryDevice.java

@@ -19,9 +19,6 @@ import net.sf.openrocket.util.MathUtil;
  * @author Sampo Niskanen <sampo.niskanen@iki.fi>
  */
 public abstract class RecoveryDevice extends MassObject implements FlightConfigurableComponent {
-	////
-	protected double PackedDiameter;
-	protected double PackedLength;
 	////
 	protected double DragCoefficient;
 	protected double cd = Parachute.DEFAULT_CD;