refactor: encapsulate islang flag in Body

Author: AlmasB

fxgl-entity/src/main/java/com/almasb/fxgl/physics/box2d/dynamics/Body.java

@@ -28,7 +28,7 @@
  * @author Daniel Murphy
  */
 public final class Body {
-    static final int e_islandFlag = 0x0001;
+    private static final int e_islandFlag = 0x0001;
 
     private static final int e_awakeFlag = 0x0002;
     private static final int e_autoSleepFlag = 0x0004;
@@ -939,6 +939,26 @@ public void setBullet(boolean flag) {
         }
     }
 
+    boolean isIslandFlagOff() {
+        return (m_flags & e_islandFlag) == 0;
+    }
+
+    boolean isIslandFlagOn() {
+        return (m_flags & e_islandFlag) != 0;
+    }
+
+    boolean isIslandFlagOn2() {
+        return (m_flags & e_islandFlag) == e_islandFlag;
+    }
+
+    void setIslandFlag(boolean flag) {
+        if (flag) {
+            m_flags |= e_islandFlag;
+        } else {
+            m_flags &= ~e_islandFlag;
+        }
+    }
+
     /**
      * You can disable sleeping on this body.
      * If you disable sleeping, the body will be woken.

fxgl-entity/src/main/java/com/almasb/fxgl/physics/box2d/dynamics/Island.java

@@ -530,7 +530,7 @@ private void report(ContactVelocityConstraint[] constraints) {
     void resetFlagsAndSynchronizeBroadphaseProxies() {
         for (int i = 0; i < bodyCount; ++i) {
             Body body = bodies[i];
-            body.m_flags &= ~Body.e_islandFlag;
+            body.setIslandFlag(false);
 
             if (body.getType() != BodyType.DYNAMIC) {
                 continue;
@@ -550,7 +550,7 @@ void postSolveCleanup() {
             // Allow static bodies to participate in other islands.
             Body b = bodies[i];
             if (b.getType() == BodyType.STATIC) {
-                b.m_flags &= ~Body.e_islandFlag;
+                b.setIslandFlag(false);
             }
         }
     }

fxgl-entity/src/main/java/com/almasb/fxgl/physics/box2d/dynamics/World.java

@@ -308,7 +308,7 @@ private void solve(TimeStep step) {
 
         // Clear all the island flags.
         for (Body b : bodies) {
-            b.m_flags &= ~Body.e_islandFlag;
+            b.setIslandFlag(false);
         }
         for (Contact c = contactManager.contactList; c != null; c = c.m_next) {
             c.m_flags &= ~Contact.ISLAND_FLAG;
@@ -324,7 +324,7 @@ private void solve(TimeStep step) {
         }
 
         for (Body seed : bodies) {
-            if ((seed.m_flags & Body.e_islandFlag) == Body.e_islandFlag) {
+            if (seed.isIslandFlagOn2()) {
                 continue;
             }
 
@@ -341,7 +341,7 @@ private void solve(TimeStep step) {
             island.clear();
             int stackCount = 0;
             stack[stackCount++] = seed;
-            seed.m_flags |= Body.e_islandFlag;
+            seed.setIslandFlag(true);
 
             // Perform a depth first search (DFS) on the constraint graph.
             while (stackCount > 0) {
@@ -386,13 +386,13 @@ private void solve(TimeStep step) {
                     Body other = ce.other;
 
                     // Was the other body already added to this island?
-                    if ((other.m_flags & Body.e_islandFlag) == Body.e_islandFlag) {
+                    if (other.isIslandFlagOn2()) {
                         continue;
                     }
 
                     assert stackCount < stackSize;
                     stack[stackCount++] = other;
-                    other.m_flags |= Body.e_islandFlag;
+                    other.setIslandFlag(true);
                 }
 
                 // Search all joints connect to this body.
@@ -411,13 +411,13 @@ private void solve(TimeStep step) {
                     island.add(je.joint);
                     je.joint.m_islandFlag = true;
 
-                    if ((other.m_flags & Body.e_islandFlag) == Body.e_islandFlag) {
+                    if (other.isIslandFlagOn2()) {
                         continue;
                     }
 
                     assert stackCount < stackSize;
                     stack[stackCount++] = other;
-                    other.m_flags |= Body.e_islandFlag;
+                    other.setIslandFlag(true);
                 }
             }
             island.solve(step, gravity, allowSleep);
@@ -428,7 +428,7 @@ private void solve(TimeStep step) {
         // Synchronize fixtures, check for out of range bodies.
         for (Body b : bodies) {
             // If a body was not in an island then it did not move.
-            if ((b.m_flags & Body.e_islandFlag) == 0) {
+            if (b.isIslandFlagOff()) {
                 continue;
             }
 
@@ -459,7 +459,7 @@ private void solveTOI(final TimeStep step) {
 
         if (stepComplete) {
             for (Body b : bodies) {
-                b.m_flags &= ~Body.e_islandFlag;
+                b.setIslandFlag(false);
                 b.m_sweep.alpha0 = 0.0f;
             }
 
@@ -613,8 +613,8 @@ private void solveTOI(final TimeStep step) {
             island.add(bB);
             island.add(minContact);
 
-            bA.m_flags |= Body.e_islandFlag;
-            bB.m_flags |= Body.e_islandFlag;
+            bA.setIslandFlag(true);
+            bB.setIslandFlag(true);
             minContact.m_flags |= Contact.ISLAND_FLAG;
 
             // Get contacts on bodyA and bodyB.
@@ -654,7 +654,7 @@ private void solveTOI(final TimeStep step) {
 
                         // Tentatively advance the body to the TOI.
                         backup1.set(other.m_sweep);
-                        if ((other.m_flags & Body.e_islandFlag) == 0) {
+                        if (other.isIslandFlagOff()) {
                             other.advance(minAlpha);
                         }
 
@@ -680,12 +680,12 @@ private void solveTOI(final TimeStep step) {
                         island.add(contact);
 
                         // Has the other body already been added to the island?
-                        if ((other.m_flags & Body.e_islandFlag) != 0) {
+                        if (other.isIslandFlagOn()) {
                             continue;
                         }
 
                         // Add the other body to the island.
-                        other.m_flags |= Body.e_islandFlag;
+                        other.setIslandFlag(true);
 
                         if (other.getType() != BodyType.STATIC) {
                             other.setAwake(true);