SoftBodySharedSettings: add the sCreateCube() method

src/main/java/com/github/stephengold/joltjni/SoftBodySharedSettings.java

@@ -1,5 +1,5 @@
 /*
-Copyright (c) 2024 Stephen Gold
+Copyright (c) 2024-2025 Stephen Gold
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
@@ -173,6 +173,22 @@ public void optimize() {
         optimize(settingsVa);
     }
 
+    /**
+     * Create a cube with edge constraints, volume constraints, and faces.
+     *
+     * @param gridSize the desired number of points on each axis (≥1)
+     * @param gridSpacing the distance between adjacent points
+     * @return a counted reference to new settings
+     */
+    public static SoftBodySharedSettingsRef sCreateCube(
+            int gridSize, float gridSpacing) {
+        long refVa = sCreateCubeNative(gridSize, gridSpacing);
+        SoftBodySharedSettingsRef result
+                = new SoftBodySharedSettingsRef(refVa, true);
+
+        return result;
+    }
+
     /**
      * Replace the materials. (native attribute: mMaterials)
      *
@@ -327,6 +343,9 @@ native static void createConstraints(long settingsVa,
 
     native private static void setEmbedded(long settingsVa);
 
+    native private static long sCreateCubeNative(
+            int gridSize, float gridSpacing);
+
     native static void setMaterialsSingle(long settingsVa, long materialVa);
 
     native private static long toRef(long settingsVa);

src/main/native/glue/s/SoftBodySharedSettings.cpp

@@ -267,6 +267,21 @@ JNIEXPORT void JNICALL Java_com_github_stephengold_joltjni_SoftBodySharedSetting
     pSettings->SetEmbedded();
 }
 
+/*
+ * Class:     com_github_stephengold_joltjni_SoftBodySharedSettings
+ * Method:    sCreateCubeNative
+ * Signature: (IF)J
+ */
+JNIEXPORT jlong JNICALL Java_com_github_stephengold_joltjni_SoftBodySharedSettings_sCreateCubeNative
+  (JNIEnv *, jclass, jint gridSize, jfloat gridSpacing) {
+    Ref<SoftBodySharedSettings> ref
+            = SoftBodySharedSettings::sCreateCube(gridSize, gridSpacing);
+    Ref<SoftBodySharedSettings> * const pResult
+            = new Ref<SoftBodySharedSettings>(ref);
+    TRACE_NEW("Ref<SoftBodySharedSettings>", pResult)
+    return reinterpret_cast<jlong> (pResult);
+}
+
 /*
  * Class:     com_github_stephengold_joltjni_SoftBodySharedSettings
  * Method:    setMaterialsSingle