From 3c74fe539ceed76f6467c13a8d74d104d467beba Mon Sep 17 00:00:00 2001
From: Stephen Gold <sgold@sonic.net>
Date: Tue, 17 Sep 2019 08:53:19 -0700
Subject: [PATCH] test and fix for issue #1138 (#1177)

---
 .../java/com/jme3/anim/TransformTrack.java    |  8 +-
 .../jme3test/animation/TestIssue1138.java     | 85 +++++++++++++++++++
 2 files changed, 90 insertions(+), 3 deletions(-)
 create mode 100644 jme3-examples/src/main/java/jme3test/animation/TestIssue1138.java

diff --git a/jme3-core/src/main/java/com/jme3/anim/TransformTrack.java b/jme3-core/src/main/java/com/jme3/anim/TransformTrack.java
index 2e53f12e0..63eba06cf 100644
--- a/jme3-core/src/main/java/com/jme3/anim/TransformTrack.java
+++ b/jme3-core/src/main/java/com/jme3/anim/TransformTrack.java
@@ -233,11 +233,13 @@ public class TransformTrack implements AnimTrack<Transform> {
         int endFrame = 1;
         float blend = 0;
         if (time >= times[lastFrame]) {
+            // extrapolate beyond the final frame of the animation
             startFrame = lastFrame;
 
-            time = time - times[startFrame] + times[startFrame - 1];
-            blend = (time - times[startFrame - 1])
-                    / (times[startFrame] - times[startFrame - 1]);
+            float inferredInterval = times[lastFrame] - times[lastFrame - 1];
+            if (inferredInterval > 0f) {
+                blend = (time - times[startFrame]) / inferredInterval;
+            }
 
         } else {
             // use lastFrame so we never overflow the array
diff --git a/jme3-examples/src/main/java/jme3test/animation/TestIssue1138.java b/jme3-examples/src/main/java/jme3test/animation/TestIssue1138.java
new file mode 100644
index 000000000..ac390aaf5
--- /dev/null
+++ b/jme3-examples/src/main/java/jme3test/animation/TestIssue1138.java
@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2019 jMonkeyEngine
+ * 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 'jMonkeyEngine' 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 OWNER 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 jme3test.animation;
+
+import com.jme3.anim.AnimComposer;
+import com.jme3.anim.Joint;
+import com.jme3.anim.SkinningControl;
+import com.jme3.app.SimpleApplication;
+import com.jme3.light.AmbientLight;
+import com.jme3.math.Vector3f;
+import com.jme3.scene.Node;
+
+/**
+ * Test case for JME issue #1138: Elephant's legUp animation sets Joint
+ * translation to NaN.
+ * <p>
+ * If successful, the animation cycle will complete without throwing an
+ * IllegalStateException.
+ *
+ * @author Stephen Gold
+ */
+public class TestIssue1138 extends SimpleApplication {
+
+    SkinningControl sControl;
+
+    public static void main(String... argv) {
+        new TestIssue1138().start();
+    }
+
+    @Override
+    public void simpleInitApp() {
+        Node cgModel = (Node) assetManager.loadModel(
+                "Models/Elephant/Elephant.mesh.xml");
+        rootNode.attachChild(cgModel);
+        cgModel.rotate(0f, -1f, 0f);
+        cgModel.scale(0.04f);
+
+        AnimComposer composer = cgModel.getControl(AnimComposer.class);
+        composer.setCurrentAction("legUp");
+        sControl = cgModel.getControl(SkinningControl.class);
+
+        AmbientLight light = new AmbientLight();
+        rootNode.addLight(light);
+    }
+
+    @Override
+    public void simpleUpdate(float tpf) {
+        for (Joint joint : sControl.getArmature().getJointList()) {
+            Vector3f translation = joint.getLocalTranslation();
+            if (!Vector3f.isValidVector(translation)) {
+                String msg = "Invalid translation for joint " + joint.getName();
+                throw new IllegalStateException(msg);
+            }
+        }
+    }
+}