refactor: use Array to store Joints instead of manual linked list

AlmasB · AlmasB · commit f41bc25552fa · 2022-03-18T18:40:39.000Z
diff --git a/fxgl-entity/src/main/java/com/almasb/fxgl/physics/box2d/dynamics/World.java b/fxgl-entity/src/main/java/com/almasb/fxgl/physics/box2d/dynamics/World.java
@@ -64,7 +64,7 @@ public final class World {
 
     private Array<Body> bodies = new Array<>(WORLD_POOL_SIZE);
 
-    private Joint m_jointList = null;
+    private Array<Joint> joints = new Array<>();
     private int jointCount = 0;
 
     private final Vec2 gravity = new Vec2();
@@ -127,13 +127,7 @@ public <T extends Joint> T createJoint(JointDef<T> def) {
 
         T j = Joint.create(this, def);
 
-        // Connect to the world list.
-        j.m_prev = null;
-        j.m_next = m_jointList;
-        if (m_jointList != null) {
-            m_jointList.m_prev = j;
-        }
-        m_jointList = j;
+        joints.add(j);
         ++jointCount;
 
         // Connect to the bodies' doubly linked lists.
@@ -177,18 +171,7 @@ public void destroyJoint(Joint j) {
 
         boolean collideConnected = j.getCollideConnected();
 
-        // Remove from the doubly linked list.
-        if (j.m_prev != null) {
-            j.m_prev.m_next = j.m_next;
-        }
-
-        if (j.m_next != null) {
-            j.m_next.m_prev = j.m_prev;
-        }
-
-        if (j == m_jointList) {
-            m_jointList = j.m_next;
-        }
+        joints.removeValueByIdentity(j);
 
         // Disconnect from island graph.
         Body bodyA = j.getBodyA();
@@ -334,7 +317,7 @@ private void solve(TimeStep step) {
         for (Contact c = contactManager.contactList; c != null; c = c.m_next) {
             c.m_flags &= ~Contact.ISLAND_FLAG;
         }
-        for (Joint j = m_jointList; j != null; j = j.m_next) {
+        for (Joint j : joints) {
             j.m_islandFlag = false;
         }
 
@@ -1149,16 +1132,6 @@ public Array<Body> getBodies() {
         return bodies;
     }
 
-    /**
-     * Get the world joint list. With the returned joint, use Joint.getNext to get the next joint in
-     * the world list. A null joint indicates the end of the list.
-     *
-     * @return the head of the world joint list.
-     */
-    public Joint getJointList() {
-        return m_jointList;
-    }
-
     /**
      * Get the world contact list. With the returned contact, use Contact.getNext to get the next
      * contact in the world list. A null contact indicates the end of the list.
diff --git a/fxgl-entity/src/main/java/com/almasb/fxgl/physics/box2d/dynamics/joints/Joint.java b/fxgl-entity/src/main/java/com/almasb/fxgl/physics/box2d/dynamics/joints/Joint.java
@@ -29,8 +29,6 @@ public static void destroy(Joint joint) {
         joint.destructor();
     }
 
-    public Joint m_prev = null;
-    public Joint m_next = null;
     public final JointEdge m_edgeA = new JointEdge();
     public final JointEdge m_edgeB = new JointEdge();
     protected Body m_bodyA;

Original file line number	Diff line number	Diff line change
`@@ -29,8 +29,6 @@ public static void destroy(Joint joint) {`
`29`	`29`	`joint.destructor();`
`30`	`30`	`}`
`31`	`31`
`32`		`- public Joint m_prev = null;`
`33`		`- public Joint m_next = null;`
`34`	`32`	`public final JointEdge m_edgeA = new JointEdge();`
`35`	`33`	`public final JointEdge m_edgeB = new JointEdge();`
`36`	`34`	`protected Body m_bodyA;`