Fix and Improve TerrainPicking

jme3-examples/src/main/java/jme3test/terrain/TerrainTestCollision.java

@@ -64,6 +64,9 @@
 import com.jme3.texture.Texture;
 import com.jme3.texture.Texture.WrapMode;
 
+import java.util.ArrayList;
+import java.util.List;
+
 /**
  * Creates a terrain object and a collision node to go with it. Then
  * drops several balls from the sky that collide with the terrain
@@ -83,7 +86,7 @@ public class TerrainTestCollision extends SimpleApplication {
     protected BitmapText hintText;
     PointLight pl;
     Geometry lightMdl;
-    Geometry collisionMarker;
+    List<Geometry> collisionMarkers;
     private BulletAppState bulletAppState;
     Geometry collisionSphere;
     Geometry collisionBox;
@@ -103,6 +106,7 @@ public void initialize() {
 
     @Override
     public void simpleInitApp() {
+        collisionMarkers = new ArrayList<>();
         bulletAppState = new BulletAppState();
         bulletAppState.setThreadingType(BulletAppState.ThreadingType.PARALLEL);
         stateManager.attach(bulletAppState);
@@ -142,6 +146,8 @@ public void simpleInitApp() {
         terrain.setLocked(false); // unlock it so we can edit the height
         rootNode.attachChild(terrain);
 
+        // if set to false, only the first collision is returned and collision is slightly faster.
+        terrain.setSupportMultipleCollisions(true);
 
         /**
          * Create PhysicsRigidBodyControl for collision
@@ -227,15 +233,19 @@ public void update() {
         super.update();
     }
 
-    private void createCollisionMarker() {
-        Sphere s = new Sphere(6, 6, 1);
-        collisionMarker = new Geometry("collisionMarker");
-        collisionMarker.setMesh(s);
-        Material mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");
-        mat.setColor("Color", ColorRGBA.Orange);
-        collisionMarker.setMaterial(mat);
-        rootNode.attachChild(collisionMarker);
+    private void createCollisionMarkers(int num) {
+        for (int i = 0; i < num; i++) {
+            Sphere s = new Sphere(6, 6, 1);
+            Geometry collisionMarker = new Geometry("collisionMarker");
+            collisionMarker.setMesh(s);
+            Material mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");
+            mat.setColor("Color", i == 0 ? ColorRGBA.Orange : ColorRGBA.Blue);
+            collisionMarker.setMaterial(mat);
+            rootNode.attachChild(collisionMarker);
+            collisionMarkers.add(collisionMarker);
+        }
     }
+
     private ActionListener actionListener = new ActionListener() {
 
         public void onAction(String binding, boolean keyPressed, float tpf) {
@@ -247,24 +257,35 @@ public void onAction(String binding, boolean keyPressed, float tpf) {
                     terrain.setMaterial(matRock);
                 }
             } else if (binding.equals("shoot") && !keyPressed) {
-
                 Vector3f origin = cam.getWorldCoordinates(new Vector2f(settings.getWidth() / 2, settings.getHeight() / 2), 0.0f);
                 Vector3f direction = cam.getWorldCoordinates(new Vector2f(settings.getWidth() / 2, settings.getHeight() / 2), 0.3f);
                 direction.subtractLocal(origin).normalizeLocal();
 
-
                 Ray ray = new Ray(origin, direction);
                 CollisionResults results = new CollisionResults();
-                int numCollisions = terrain.collideWith(ray, results);
-                if (numCollisions > 0) {
-                    CollisionResult hit = results.getClosestCollision();
-                    if (collisionMarker == null) {
-                        createCollisionMarker();
+
+                if (terrain.collideWith(ray, results) > 0) {
+                    CollisionResult hit = results.getClosestCollision(); // sorts the collection before printing
+                    printCollisions(results);
+
+                    // Remove old markers.
+                    for (Geometry g: collisionMarkers) {
+                        g.removeFromParent();
                     }
+                    collisionMarkers.clear();
+
+                    createCollisionMarkers(results.size());
+
+                    // Position Closest Collision
                     Vector2f loc = new Vector2f(hit.getContactPoint().x, hit.getContactPoint().z);
                     float height = terrain.getHeight(loc);
-                    System.out.println("collide " + hit.getContactPoint() + ", height: " + height + ", distance: " + hit.getDistance());
-                    collisionMarker.setLocalTranslation(new Vector3f(hit.getContactPoint().x, height, hit.getContactPoint().z));
+                    System.out.println("Closest Collision: " + hit.getContactPoint() + ", height: " + height + ", distance: " + hit.getDistance());
+                    collisionMarkers.get(0).setLocalTranslation(new Vector3f(hit.getContactPoint().x, height, hit.getContactPoint().z));
+
+                    // Position Rest: When getClosestCollision has been called, the results are sorted, and thus 0 is closest.
+                    for (int i = 1; i < results.size(); i++) {
+                        collisionMarkers.get(i).setLocalTranslation(results.getCollision(i).getContactPoint());
+                    }
                 }
             } else if (binding.equals("cameraDown") && !keyPressed) {
                 getCamera().lookAtDirection(new Vector3f(0, -1, 0), Vector3f.UNIT_Y);
@@ -302,4 +323,14 @@ private void testCollision(Vector3f oldLoc) {
             selectedCollisionObject.setLocalTranslation(oldLoc);
         }
     }
+
+    private void printCollisions(CollisionResults cr) {
+        System.out.println("================ Collision Results ================");
+        for (int i = 0; i < cr.size(); i++) {
+            CollisionResult res = cr.getCollision(i);
+            System.out.println("Result " + i);
+            System.out.println("\t\t" + res.toString());
+        }
+        System.out.println("================ END Collision Results ================");
+    }
 }

jme3-terrain/build.gradle

@@ -4,4 +4,8 @@ if (!hasProperty('mainClass')) {
 
 dependencies {
     compile project(':jme3-core')
+    testCompile project(':jme3-core')
+    testCompile project(':jme3-desktop')
+    testCompile project(':jme3-core').sourceSets.test.output
+    testCompile project(':jme3-testdata')
 }

jme3-terrain/src/main/java/com/jme3/terrain/geomipmap/TerrainQuad.java

@@ -123,7 +123,7 @@ public class TerrainQuad extends Node implements Terrain {
     private int maxLod = -1;
     private BoundingBox affectedAreaBBox; // only set in the root quad
 
-    private TerrainPicker picker;
+    private TerrainPicker picker = new BresenhamTerrainPicker(this);
     private Vector3f lastScale = Vector3f.UNIT_XYZ;
 
     protected NeighbourFinder neighbourFinder;
@@ -274,20 +274,7 @@ protected void cacheTerrainTransforms() {
     }
 
     private int collideWithRay(Ray ray, CollisionResults results) {
-        if (picker == null)
-            picker = new BresenhamTerrainPicker(this);
-
-        Vector3f intersection = picker.getTerrainIntersection(ray, results);
-        if (intersection != null) {
-            if (ray.getLimit() < Float.POSITIVE_INFINITY) {
-                if (results.getClosestCollision().getDistance() <= ray.getLimit())
-                    return 1; // in range
-                else
-                    return 0; // out of range
-            } else
-                return 1;
-        } else
-            return 0;
+        return picker.getTerrainIntersection(ray, results);
     }
 
     /**
@@ -1915,5 +1902,23 @@ else if(((TerrainPatch) s).getQuadrant() == 4)
 
         return hm;
     }
+
+    /**
+     * When colliding with this terrain, is a report of all collisions wanted or only the closest collision?<br>
+     * If only the closest collision is required, the collision calculation will be faster.<br>
+     * Note: If no collision happens, it takes as long as a collision with multipleCollisions on would take.
+     *
+     * @param set Whether to support multiple collisions or not
+     */
+    public void setSupportMultipleCollisions(boolean set) {
+        if (picker == null) {
+            // This is so that it doesn't fail at the IllegalStateException because null !instanceof Anything
+            throw new NullPointerException("TerrainPicker is null");
+        } else if (picker instanceof BresenhamTerrainPicker) {
+            ((BresenhamTerrainPicker)picker).setSupportMultipleCollisions(set);
+        } else {
+            throw new IllegalStateException("The underlying picking implementation does not support multiple collisions");
+        }
+    }
 }