OBJLoader enhancement: named groups support

Author: kkolyan

jme3-core/build.gradle

@@ -17,6 +17,10 @@ sourceSets {
     }
 }
 
+dependencies {
+    testCompile project(':jme3-testdata')
+}
+
 task updateVersionPropertiesFile {
     def versionFile = file('src/main/resources/com/jme3/system/version.properties')
     def versionFileText = "# THIS IS AN AUTO-GENERATED FILE..\n" +

jme3-core/src/plugins/java/com/jme3/scene/plugins/MTLLoader.java

@@ -152,6 +152,7 @@ protected void createMaterial(){
             material.setFloat("AlphaDiscardThreshold", 0.01f);
         }
 
+        material.setName(matName);
         matList.put(matName, material);
     }
 

jme3-core/src/plugins/java/com/jme3/scene/plugins/OBJLoader.java

@@ -66,10 +66,9 @@ public final class OBJLoader implements AssetLoader {
     protected final ArrayList<Vector3f> verts = new ArrayList<Vector3f>();
     protected final ArrayList<Vector2f> texCoords = new ArrayList<Vector2f>();
     protected final ArrayList<Vector3f> norms = new ArrayList<Vector3f>();
-    
-    protected final ArrayList<Face> faces = new ArrayList<Face>();
-    protected final HashMap<String, ArrayList<Face>> matFaces = new HashMap<String, ArrayList<Face>>();
-    
+
+    private final ArrayList<Group> groups = new ArrayList<Group>();
+
     protected String currentMatName;
     protected String currentObjectName;
 
@@ -87,6 +86,16 @@ public final class OBJLoader implements AssetLoader {
     protected String objName;
     protected Node objNode;
 
+    private static class Group {
+        private String name;
+        private final ArrayList<Face> faces = new ArrayList<Face>();
+        private final HashMap<String, ArrayList<Face>> matFaces = new HashMap<String, ArrayList<Face>>();
+
+        public Group(final String name) {
+            this.name = name;
+        }
+    }
+
     protected static class Vertex {
 
         Vector3f v;
@@ -164,8 +173,7 @@ public void reset(){
         verts.clear();
         texCoords.clear();
         norms.clear();
-        faces.clear();
-        matFaces.clear();
+        groups.clear();
 
         vertIndexMap.clear();
         indexVertMap.clear();
@@ -289,10 +297,17 @@ protected void readFace(){
             f.verticies[i] = vertList.get(i);
         }
 
-        if (matList != null && matFaces.containsKey(currentMatName)){
-            matFaces.get(currentMatName).add(f);
+        Group group = groups.get(groups.size() - 1);
+
+        if (currentMatName != null && matList != null && matList.containsKey(currentMatName)){
+            ArrayList<Face> matFaces = group.matFaces.get(currentMatName);
+            if (matFaces == null) {
+                matFaces = new ArrayList<Face>();
+                group.matFaces.put(currentMatName, matFaces);
+            }
+            matFaces.add(f);
         }else{
-            faces.add(f); // faces that belong to the default material
+            group.faces.add(f); // faces that belong to the default material
         }
     }
 
@@ -337,13 +352,6 @@ protected void loadMtlLib(String name) throws IOException{
         } catch (AssetNotFoundException ex){
             logger.log(Level.WARNING, "Cannot locate {0} for model {1}", new Object[]{name, key});
         }
-
-        if (matList != null){
-            // create face lists for every material
-            for (String matName : matList.keySet()){
-                matFaces.put(matName, new ArrayList<Face>());
-            }
-        }
     }
 
     protected boolean nextStatement(){
@@ -387,8 +395,14 @@ protected boolean readLine() throws IOException{
             // specify MTL lib to use for this OBJ file
             String mtllib = scan.nextLine().trim();
             loadMtlLib(mtllib);
-        }else if (cmd.equals("s") || cmd.equals("g")){
+        }else if (cmd.equals("s")) {
+            logger.log(Level.WARNING, "smoothing groups are not supported, statement ignored: {0}", cmd);
+            return nextStatement();
+        }else if (cmd.equals("mg")) {
+            logger.log(Level.WARNING, "merge groups are not supported, statement ignored: {0}", cmd);
             return nextStatement();
+        }else if (cmd.equals("g")) {
+            groups.add(new Group(scan.nextLine().trim()));
         }else{
             // skip entire command until next line
             logger.log(Level.WARNING, "Unknown statement in OBJ! {0}", cmd);
@@ -565,11 +579,14 @@ public Object load(AssetInfo info) throws IOException{
         }
 
         objNode = new Node(objName + "-objnode");
+    
+        Group defaultGroupStub = new Group(null);
+        groups.add(defaultGroupStub);
 
         if (!(info.getKey() instanceof ModelKey))
             throw new IllegalArgumentException("Model assets must be loaded using a ModelKey");
 
-        InputStream in = null; 
+        InputStream in = null;
         try {
             in = info.openStream();
 
@@ -583,25 +600,43 @@ public Object load(AssetInfo info) throws IOException{
             }
         }
 
-        if (matFaces.size() > 0){
-            for (Entry<String, ArrayList<Face>> entry : matFaces.entrySet()){
-                ArrayList<Face> materialFaces = entry.getValue();
-                if (materialFaces.size() > 0){
-                    Geometry geom = createGeometry(materialFaces, entry.getKey());
+        for (Group group : groups) {
+            if (group == defaultGroupStub) {
+                materializeGroup(group, objNode);
+            } else {
+                Node groupNode = new Node(group.name);
+                materializeGroup(group, groupNode);
+                if (groupNode.getQuantity() == 1) {
+                    Spatial geom = groupNode.getChild(0);
+                    geom.setName(groupNode.getName());
                     objNode.attachChild(geom);
+                } else if (groupNode.getQuantity() > 1) {
+                    objNode.attachChild(groupNode);
                 }
             }
-        }else if (faces.size() > 0){
-            // generate final geometry
-            Geometry geom = createGeometry(faces, null);
-            objNode.attachChild(geom);
         }
 
         if (objNode.getQuantity() == 1)
             // only 1 geometry, so no need to send node
-            return objNode.getChild(0); 
+            return objNode.getChild(0);
         else
             return objNode;
     }
- 
+    
+    private void materializeGroup(Group group, Node container) throws IOException {
+        if (group.matFaces.size() > 0) {
+            for (Entry<String, ArrayList<Face>> entry : group.matFaces.entrySet()){
+                ArrayList<Face> materialFaces = entry.getValue();
+                if (materialFaces.size() > 0){
+                    Geometry geom = createGeometry(materialFaces, entry.getKey());
+                    container.attachChild(geom);
+                }
+            }
+        } else if (group.faces.size() > 0) {
+            // generate final geometry
+            Geometry geom = createGeometry(group.faces, null);
+            container.attachChild(geom);
+        }
+    }
+    
 }

jme3-core/src/test/java/com/jme3/scene/plugins/OBJLoaderTest.java

@@ -0,0 +1,75 @@
+package com.jme3.scene.plugins;
+
+import com.jme3.asset.AssetInfo;
+import com.jme3.asset.AssetLoader;
+import com.jme3.asset.AssetManager;
+import com.jme3.asset.ModelKey;
+import com.jme3.scene.Geometry;
+import com.jme3.scene.Node;
+import com.jme3.scene.Spatial;
+import com.jme3.system.TestUtil;
+import com.jme3.texture.Image;
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class OBJLoaderTest {
+    private AssetManager assetManager;
+    
+    @Before
+    public void init() {
+        assetManager = TestUtil.createAssetManager();
+        // texture loaders are outside of core, so creating stub
+        assetManager.registerLoader(PngLoaderStub.class, "png");
+        
+    }
+    
+    @Test
+    public void testHappyPath() {
+        Node scene = (Node) assetManager.loadModel(new ModelKey("OBJLoaderTest/TwoChairs.obj"));
+        String sceneAsString = toDiffFriendlyString("", scene);
+        System.out.println(sceneAsString);
+        String expectedText = "" +
+            // generated root name (as before named groups support)
+            "TwoChairs-objnode\n" +
+            // unnamed geometry with generated name (as before named groups support).
+            // actually it's partially smoothed, but this fact is ignored.
+            "  TwoChairs-geom-0 (material: dot_purple)\n" +
+            // named group as Geometry
+            "  Chair 2 (material: dot_purple)\n" +
+            // named group as Geometry
+            "  Pillow 2 (material: dot_red)\n" +
+            // named group as node with two dufferent Geometry instances,
+            // because two materials are used (as before named groups support)
+            "  Podium\n" +
+            "    TwoChairs-geom-3 (material: dot_red)\n" +
+            "    TwoChairs-geom-4 (material: dot_blue)\n" +
+            // named group as Geometry
+            "  Pillow 1 (material: dot_green)";
+        assertEquals(expectedText, sceneAsString.trim());
+    }
+    
+    private static String toDiffFriendlyString(String indent, Spatial spatial) {
+        if (spatial instanceof Geometry) {
+            return indent + spatial.getName() + " (material: "+((Geometry) spatial).getMaterial().getName()+")\n";
+        }
+        if (spatial instanceof Node) {
+            StringBuilder s = new StringBuilder();
+            s.append(indent).append(spatial.getName()).append("\n");
+            Node node = (Node) spatial;
+            for (final Spatial child : node.getChildren()) {
+                s.append(toDiffFriendlyString(indent + "  ", child));
+            }
+            return s.toString();
+        }
+        return indent + spatial + "\n";
+    }
+    
+    public static class PngLoaderStub implements AssetLoader {
+        @Override
+        public Object load(final AssetInfo assetInfo) {
+            return new Image();
+        }
+    }
+}

jme3-examples/src/main/java/jme3test/model/TestObjGroupsLoading.java

@@ -0,0 +1,75 @@
+package jme3test.model;
+
+import com.jme3.app.SimpleApplication;
+import com.jme3.asset.ModelKey;
+import com.jme3.collision.CollisionResult;
+import com.jme3.collision.CollisionResults;
+import com.jme3.font.BitmapFont;
+import com.jme3.font.BitmapText;
+import com.jme3.font.Rectangle;
+import com.jme3.light.AmbientLight;
+import com.jme3.math.ColorRGBA;
+import com.jme3.math.Ray;
+import com.jme3.math.Vector3f;
+import com.jme3.scene.Spatial;
+
+public class TestObjGroupsLoading extends SimpleApplication {
+    
+    public static void main(String[] args) {
+        TestObjGroupsLoading app = new TestObjGroupsLoading();
+        app.start();
+    }
+    
+    private BitmapText pointerDisplay;
+    
+    @Override
+    public void simpleInitApp() {
+    
+        // load scene with following structure:
+        // Chair 1 (just mesh without name) and named groups: Chair 2, Pillow 2, Podium
+        Spatial scene = assetManager.loadModel(new ModelKey("OBJLoaderTest/TwoChairs.obj"));
+        // add light to make it visible
+        scene.addLight(new AmbientLight(ColorRGBA.White));
+        // attach scene to the root
+        rootNode.attachChild(scene);
+        
+        // configure camera for best scene viewing
+        cam.setLocation(new Vector3f(-3, 4, 3));
+        cam.lookAtDirection(new Vector3f(0, -0.5f, -1), Vector3f.UNIT_Y);
+        flyCam.setMoveSpeed(10);
+        
+        // create display to indicate pointed geometry name
+        pointerDisplay = new BitmapText(guiFont);
+        pointerDisplay.setBox(new Rectangle(0, settings.getHeight(), settings.getWidth(), settings.getHeight()));
+        pointerDisplay.setAlignment(BitmapFont.Align.Center);
+        pointerDisplay.setVerticalAlignment(BitmapFont.VAlign.Center);
+        guiNode.attachChild(pointerDisplay);
+    }
+    
+    @Override
+    public void simpleUpdate(final float tpf) {
+        
+        // ray to the center of the screen from the camera
+        Ray ray = new Ray(cam.getLocation(), cam.getDirection());
+        
+        // find object at the center of the screen
+    
+        final CollisionResults results = new CollisionResults();
+        rootNode.collideWith(ray, results);
+        
+        CollisionResult result = results.getClosestCollision();
+        if (result == null) {
+            pointerDisplay.setText("");
+        } else {
+            // display pointed geometry and it's parents names
+            StringBuilder sb = new StringBuilder();
+            for (Spatial node = result.getGeometry(); node != null; node = node.getParent()) {
+                if (sb.length() > 0) {
+                    sb.append(" < ");
+                }
+                sb.append(node.getName());
+            }
+            pointerDisplay.setText(sb);
+        }
+    }
+}

jme3-testdata/src/main/resources/OBJLoaderTest/TwoChairs.mtl

@@ -0,0 +1,20 @@
+newmtl dot_purple
+map_Kd -o 0 0 -s 1 1 dot_purple.png
+Kd 1 1 1
+d 1
+
+newmtl dot_red
+map_Kd -o 0 0 -s 1 1 dot_red.png
+Kd 1 1 1
+d 1
+
+newmtl dot_blue
+map_Kd -o 0 0 -s 1 1 dot_blue.png
+Kd 1 1 1
+d 1
+
+newmtl dot_green
+map_Kd -o 0 0 -s 1 1 dot_green.png
+Kd 1 1 1
+d 1
+