Anchor: add the setPivotInB() method

src/main/java/com/jme3/bullet/joints/Anchor.java

@@ -187,10 +187,23 @@ public int nodeIndex() {
     public void setInfluence(float amount) {
         Validate.fraction(amount, "amount");
 
-        long anchorId = nativeId();
         this.influence = amount;
+        long anchorId = nativeId();
         setInfluence(anchorId, amount);
     }
+
+    /**
+     * Alter the pivot location in B's local coordinates.
+     *
+     * @param location the desired location (not null, unaffected)
+     */
+    public void setPivotInB(Vector3f location) {
+        Validate.nonNull(location, "location");
+
+        pivotInB.set(location);
+        long archorId = nativeId();
+        setPivotInB(archorId, location);
+    }
     // *************************************************************************
     // PhysicsJoint methods
 
@@ -230,4 +243,6 @@ native private static long createAnchor(long softBodyId, int nodeIndex,
             float influence);
 
     native private static void setInfluence(long anchorId, float influence);
+
+    native private static void setPivotInB(long anchorId, Vector3f location);
 }

src/main/native/glue/com_jme3_bullet_joints_Anchor.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019-2020 jMonkeyEngine
+ * Copyright (c) 2019-2021 jMonkeyEngine
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -82,3 +82,18 @@ JNIEXPORT void JNICALL Java_com_jme3_bullet_joints_Anchor_setInfluence
 
     pAnchor->m_influence = (btScalar) influence;
 }
+
+/*
+ * Class:     com_jme3_bullet_joints_Anchor
+ * Method:    setPivotInB
+ * Signature: (JLcom/jme3/math/Vector3f;)V
+ */
+JNIEXPORT void JNICALL Java_com_jme3_bullet_joints_Anchor_setPivotInB
+(JNIEnv *pEnv, jclass, jlong anchorId, jobject locationVector) {
+    btSoftBody::Anchor *pAnchor
+            = reinterpret_cast<btSoftBody::Anchor *> (anchorId);
+    NULL_CHK(pEnv, pAnchor, "The btSoftBody::Anchor does not exist.",)
+    NULL_CHK(pEnv, locationVector, "The location vector does not exist.",)
+
+    jmeBulletUtil::convert(pEnv, locationVector, &pAnchor->m_local);
+}