MinieExamples: add the TestManyBoxes app

MinieExamples/build.gradle

@@ -166,6 +166,9 @@ tasks.register('TestIssue9', JavaExec) {
 tasks.register('TestLargeMesh', JavaExec) {
     mainClass = 'jme3utilities.minie.test.issue.TestLargeMesh'
 }
+tasks.register('TestManyBoxes', JavaExec) {
+    mainClass = 'jme3utilities.minie.test.issue.TestManyBoxes'
+}
 tasks.register('TestMultiBody', JavaExec) {
     mainClass = 'jme3utilities.minie.test.TestMultiBody'
 }

MinieExamples/src/main/java/jme3utilities/minie/test/issue/TestManyBoxes.java

@@ -0,0 +1,185 @@
+/*
+ Copyright (c) 2024 Stephen Gold
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are met:
+ * Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above copyright
+ notice, this list of conditions and the following disclaimer in the
+ documentation and/or other materials provided with the distribution.
+ * Neither the name of the copyright holder nor the names of its contributors
+ may be used to endorse or promote products derived from this software without
+ specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package jme3utilities.minie.test.issue;
+
+import com.jme3.app.SimpleApplication;
+import com.jme3.bullet.BulletAppState;
+import com.jme3.bullet.PhysicsSpace;
+import com.jme3.bullet.collision.shapes.BoxCollisionShape;
+import com.jme3.bullet.control.RigidBodyControl;
+import com.jme3.font.BitmapText;
+import com.jme3.material.Material;
+import com.jme3.material.Materials;
+import com.jme3.math.ColorRGBA;
+import com.jme3.math.Quaternion;
+import com.jme3.math.Vector3f;
+import com.jme3.scene.Geometry;
+import com.jme3.scene.shape.Box;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+import jme3utilities.Heart;
+
+/**
+ * The "fountain of boxes" stress test to estimate how many active dynamic rigid
+ * bodies can be simulated while rendering 30 frames per second.
+ *
+ * @author Stephen Gold [email protected]
+ */
+public class TestManyBoxes extends SimpleApplication {
+    // *************************************************************************
+    // constants and loggers
+
+    /**
+     * message logger for this class
+     */
+    final public static Logger logger
+            = Logger.getLogger(TestManyBoxes.class.getName());
+    // *************************************************************************
+    // fields
+
+    private static BitmapText statusDisplay;
+    private static Box smallBox;
+    private static BoxCollisionShape smallBoxShape;
+    private static float secondsSinceFpsUpdate = 0f;
+    private static int framesSinceFpsUpdate = 0;
+    private static int numBoxes = 1;
+    private static Material solidGray;
+    private static PhysicsSpace physicsSpace;
+    // *************************************************************************
+    // new methods exposed
+
+    /**
+     * Main entry point for the TestManyBoxes application.
+     *
+     * @param arguments unused
+     */
+    public static void main(String[] arguments) {
+        TestManyBoxes app = new TestManyBoxes();
+        app.start();
+    }
+    // *************************************************************************
+    // SimpleApplication methods
+
+    /**
+     * Initialize the application.
+     */
+    @Override
+    public void simpleInitApp() {
+        if (Heart.areAssertionsEnabled()) {
+            System.out.println("Warning: assertions are enabled.");
+        }
+
+        // Disable logging of rigid-body creation:
+        Logger prbLogger
+                = Logger.getLogger("com.jme3.bullet.objects.PhysicsRigidBody");
+        prbLogger.setLevel(Level.SEVERE);
+
+        // Pre-position the main camera and disable FlyByCamera:
+        cam.setLocation(new Vector3f(0f, 110f, 210f));
+        cam.setRotation(new Quaternion(0f, 0.9777315f, -0.20985f, 0.00143f));
+        flyCam.setEnabled(false);
+
+        // Attach a simple status display to the GUI node:
+        statusDisplay = new BitmapText(loadGuiFont());
+        statusDisplay.setLocalTranslation(0f, settings.getHeight(), 0f);
+        guiNode.attachChild(statusDisplay);
+
+        // Create a high-gravity PhysicsSpace:
+        BulletAppState bulletAppState = new BulletAppState();
+        bulletAppState.setBroadphaseType(
+                PhysicsSpace.BroadphaseType.AXIS_SWEEP_3); // default = DBVT
+        bulletAppState.setWorldMax(new Vector3f(100f, 50f, 100f));
+        bulletAppState.setWorldMin(new Vector3f(-100f, -200f, -100f));
+        stateManager.attach(bulletAppState);
+        physicsSpace = bulletAppState.getPhysicsSpace();
+        physicsSpace.setGravity(new Vector3f(0f, -99f, 0f));
+        physicsSpace.setMaxSubSteps(1); // IMPORTANT! default = 4
+        System.out.printf("maxSubSteps = %d, numSolvers = %d%n",
+                physicsSpace.maxSubSteps(), physicsSpace.countSolvers());
+
+        // Add a big blue box to serve as a platform:
+        float size = 99f; // half extent in world units
+        Box bigBox = new Box(size, size, size);
+        BoxCollisionShape bigBoxShape
+                = new BoxCollisionShape(new Vector3f(size, size, size));
+        Material solidBlue = new Material(assetManager, Materials.UNSHADED);
+        solidBlue.setColor("Color", ColorRGBA.Blue);
+
+        RigidBodyControl staticRbc = new RigidBodyControl(bigBoxShape, 0f);
+        staticRbc.setPhysicsSpace(physicsSpace);
+
+        Geometry bbGeom = new Geometry("BigBox", bigBox);
+        rootNode.attachChild(bbGeom);
+        bbGeom.move(0f, -size, 0f);
+        bbGeom.addControl(staticRbc);
+        bbGeom.setMaterial(solidBlue);
+
+        smallBox = new Box(1f, 1f, 1f);
+        smallBoxShape = new BoxCollisionShape(new Vector3f(1f, 1f, 1f));
+
+        solidGray = new Material(assetManager, Materials.UNSHADED);
+        solidGray.setColor("Color", ColorRGBA.DarkGray);
+    }
+
+    /**
+     * Callback invoked once per frame to add a box and update statistics.
+     *
+     * @param tpf the time interval between frames (in seconds, ≥0)
+     */
+    @Override
+    public void simpleUpdate(float tpf) {
+        // Drop a small, gray, dynamic box from (0, 40, 0):
+        RigidBodyControl dynamicRbc = new RigidBodyControl(smallBoxShape, 1f);
+        dynamicRbc.setPhysicsSpace(physicsSpace);
+
+        Geometry sbGeom = new Geometry("", smallBox);
+        rootNode.attachChild(sbGeom);
+        sbGeom.move(0f, 40f, 0f);
+        sbGeom.addControl(dynamicRbc);
+        sbGeom.setMaterial(solidGray);
+        ++numBoxes;
+
+        // Update the status:
+        String statusText = "numBoxes = " + numBoxes;
+        statusDisplay.setText(statusText);
+
+        // Update the FPS statistics:
+        secondsSinceFpsUpdate += tpf;
+        ++framesSinceFpsUpdate;
+        if (secondsSinceFpsUpdate >= 1f) {
+            // Calculate frames per second over a 1-second interval:
+            float fps = framesSinceFpsUpdate / secondsSinceFpsUpdate;
+            if (fps < 30f) {
+                // Terminate the application if FPS drops below 30:
+                System.out.println(statusText);
+                stop();
+            }
+            secondsSinceFpsUpdate = 0f;
+            framesSinceFpsUpdate = 0;
+        }
+    }
+}