Added TerrainTrackControl.java

src/docs/asciidoc/jme3/advanced/sourcecode.adoc

@@ -306,6 +306,109 @@ public class QuixoteControl extends AbstractControl {
 
 ----
 
+.TerrainTrackControl.java
+
+[source,java]
+----
+
+package mygame;
+
+import com.jme3.collision.CollisionResult;
+import com.jme3.collision.CollisionResults;
+import com.jme3.export.InputCapsule;
+import com.jme3.export.JmeExporter;
+import com.jme3.export.JmeImporter;
+import com.jme3.export.OutputCapsule;
+import com.jme3.math.Ray;
+import com.jme3.math.Vector3f;
+import com.jme3.renderer.RenderManager;
+import com.jme3.renderer.ViewPort;
+import com.jme3.scene.Spatial;
+import com.jme3.scene.control.AbstractControl;
+import com.jme3.scene.control.Control;
+import java.io.IOException;
+import java.util.Iterator;
+
+/** 
+ * 
+ * @author normenhansen 
+ */
+public class TerrainTrackControl extends AbstractControl {    
+    //Any local variables should be encapsulated by getters/setters so they    
+    //appear in the SDK properties window and can be edited.    
+    //Right-click a local variable to encapsulate it with getters and setters.    
+    private final Ray ray = new Ray(Vector3f.ZERO.clone(), new Vector3f(0, -1, 0));    
+    private final Vector3f up = new Vector3f(0, 50, 0);    
+    private final CollisionResults results = new CollisionResults();    
+    private final float offset = 0.5f;    
+    private Spatial terrain;        
+
+    public TerrainTrackControl() {            
+    
+    }        
+    
+    @Override    
+    protected void controlUpdate(float tpf) {        
+        terrain = spatial.getParent();        
+        if (terrain != null) {            
+            ray.setOrigin(spatial.getWorldTranslation().add(up));            
+            ray.setLimit(100);            
+            results.clear();            
+            terrain.collideWith(ray, results);            
+            for (Iterator<CollisionResult> it = results.iterator(); it.hasNext(); ) {                
+                CollisionResult collisionResult = it.next();                
+                if (isTerrain(collisionResult.getGeometry()) ) {                    
+                    Vector3f loc = collisionResult.getContactPoint();                    
+                    spatial.setLocalTranslation(spatial.getLocalTranslation().setY(loc.getY() * offset));
+                    return;                
+                }            
+            }        
+        }    
+    }        
+    
+    private boolean isTerrain(Spatial spat) {        
+        while (true) {            
+            if (spat == null) {                
+                return false;            
+            } else if ("terrain".equals(spat.getName())) {                
+                return true;            
+            }            
+            spat = spat.getParent();        
+        }    
+    }
+    
+    @Override    
+    protected void controlRender(RenderManager rm, ViewPort vp) {        
+        //Only needed for rendering-related operations,        
+        //not called when spatial is culled.    
+    }
+    
+    @Override    
+    public Control cloneForSpatial(Spatial spatial) {        
+        TerrainTrackControl control = new TerrainTrackControl();        
+        //TODO: copy parameters to new Control        
+        control.setSpatial(spatial);        
+        return control;    
+    }
+    
+    @Override    
+    public void read(JmeImporter im) throws IOException {        
+        super.read(im);        
+        InputCapsule in = im.getCapsule(this);        
+        //TODO: load properties of this Control, e.g.        
+        //this.value = in.readFloat("name", defaultValue);    
+    }
+    
+    @Override    
+    public void write(JmeExporter ex) throws IOException {        
+        super.write(ex);        
+        OutputCapsule out = ex.getCapsule(this);        
+        //TODO: save properties of this Control, e.g.        
+        //out.write(this.value, "name", defaultValue);    
+    }
+}
+
+----
 .AnimUpdateControl.java
 
 [source,java]