Where possible, merge meshes with identical attributes.

git-svn-id: svn+ssh://src.earth.threerings.net/nenya/trunk@201 ed5b42cb-e716-0410-a449-f6a68f950b19

src/java/com/threerings/jme/model/ModelMesh.java

@@ -29,6 +29,7 @@ import java.nio.FloatBuffer;
 import java.nio.IntBuffer;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Properties;
 
 import com.jme.bounding.BoundingBox;
@@ -141,6 +142,51 @@ public class ModelMesh extends TriMesh
             Boolean.parseBoolean(tprops.getProperty("translucent"));
     }
 
+    /**
+     * Returns an opaque object representing this mesh's attributes.  The
+     * object will implement {@link Object#hashCode} and {@link Object#equals}
+     * so that meshes with the same attributes will have identical keys.
+     */
+    public Object getAttributeKey ()
+    {
+        return new AttributeKey(_textureKey, _textures, _sphereMapped,
+            _filterMode, _mipMapMode, _emissiveMap, _emissive, _additive,
+            _solid, _transparent, _alphaThreshold, _translucent);
+    }
+
+    /**
+     * Merges another mesh into this one.  The mesh is assumed to be in the same coordinate system
+     * and have the same attributes.
+     */
+    public void merge (ModelMesh mesh)
+    {
+        TriangleBatch batch = (TriangleBatch)getBatch(0);
+        TriangleBatch mbatch = (TriangleBatch)mesh.getBatch(0);
+
+        int vcount = batch.getVertexCount();
+        batch.setVertexBuffer(concatenate(batch.getVertexBuffer(), mbatch.getVertexBuffer()));
+        batch.setNormalBuffer(concatenate(batch.getNormalBuffer(), mbatch.getNormalBuffer()));
+        if (batch.getColorBuffer() != null && mbatch.getColorBuffer() != null) {
+            batch.setColorBuffer(concatenate(batch.getColorBuffer(), mbatch.getColorBuffer()));
+        }
+        batch.setTextureBuffer(concatenate(
+            batch.getTextureBuffer(0), mbatch.getTextureBuffer(0)), 0);
+        for (int ii = 1, nn = getTextureCount(); ii < nn; ii++) {
+            batch.setTextureBuffer(batch.getTextureBuffer(0), ii);
+        }
+
+        IntBuffer ibuf = batch.getIndexBuffer(), mibuf = mbatch.getIndexBuffer();
+        IntBuffer nibuf = BufferUtils.createIntBuffer(ibuf.capacity() + mibuf.capacity());
+        ibuf.clear();
+        nibuf.put(ibuf);
+        mibuf.clear();
+        while (mibuf.hasRemaining()) {
+            nibuf.put(mibuf.get() + vcount);
+        }
+        nibuf.clear();
+        batch.setIndexBuffer(nibuf);
+    }
+
     /**
      * Adjusts the vertices and the transform of the mesh so that the mesh's
      * position lies at the center of its bounding volume.
@@ -588,6 +634,20 @@ public class ModelMesh extends TriMesh
         return astate;
     }
 
+    /**
+     * Concatenates the two provided buffers.
+     */
+    protected static FloatBuffer concatenate (FloatBuffer b1, FloatBuffer b2)
+    {
+        FloatBuffer nb = BufferUtils.createFloatBuffer(b1.capacity() + b2.capacity());
+        b1.clear();
+        nb.put(b1);
+        b2.clear();
+        nb.put(b2);
+        nb.clear();
+        return nb;
+    }
+
     /**
      * Sorts the encoded triangle index/distance pairs in {@link #_tcodes}
      * using a two-pass (16 bit) radix sort (as described by
@@ -745,8 +805,29 @@ public class ModelMesh extends TriMesh
             new RenderState[RenderState.RS_MAX_STATE];
     }
 
-    /** The type of bounding volume that this mesh should use. */
+    /** A wrapper around an array of attributes that uses {@link Arrays#deepHashCode} and
-    protected int _boundingType;
+     * {@link Arrays#deepEquals} for hashing/comparison. */
+    protected static class AttributeKey
+    {
+        public AttributeKey (Object... attrs)
+        {
+            _attrs = attrs;
+        }
+
+        @Override // documentation inherited
+        public int hashCode ()
+        {
+            return Arrays.deepHashCode(_attrs);
+        }
+
+        @Override // documentation inherited
+        public boolean equals (Object other)
+        {
+            return Arrays.deepEquals(_attrs, ((AttributeKey)other)._attrs);
+        }
+
+        protected Object[] _attrs;
+    }
 
     /** The name of the texture specified in the model file, which acts as a
      * property key and a default value. */

src/java/com/threerings/jme/tools/ModelDef.java

@@ -39,7 +39,9 @@ import java.util.Set;
 import com.jme.bounding.BoundingBox;
 import com.jme.bounding.BoundingSphere;
 import com.jme.math.FastMath;
+import com.jme.math.Vector3f;
 import com.jme.scene.Spatial;
+import com.jme.scene.batch.GeomBatch;
 import com.jme.util.geom.BufferUtils;
 
 import com.samskivert.util.PropertiesUtil;
@@ -51,6 +53,7 @@ import com.threerings.jme.model.ModelController;
 import com.threerings.jme.model.ModelMesh;
 import com.threerings.jme.model.ModelNode;
 import com.threerings.jme.model.SkinMesh;
+import com.threerings.jme.util.SpatialVisitor;
 
 /**
  * An intermediate representation for models used to store data parsed from
@@ -435,9 +438,6 @@ public class ModelDef
     {
         Model model = new Model(props.getProperty("name", "model"), props);
 
-        // set the overall scale
-        model.setLocalScale(Float.parseFloat(props.getProperty("scale", "1")));
-        
         // start by creating the spatials and mapping them to their names
         for (int ii = 0, nn = spatials.size(); ii < nn; ii++) {
             Spatial spatial = spatials.get(ii).getSpatial(props);
@@ -471,12 +471,21 @@ public class ModelDef
             ModelController ctrl = createController(subProps, target);
             if (ctrl != null) {
                 model.addController(ctrl);
+                referenced.add(target);
             }
         }
 
+        // in non-animated models, merge meshes with the same attributes
+        if (StringUtil.isBlank(props.getProperty("animations"))) {
+            mergeEquivalentMeshes(model, nodes, referenced);
+        }
+
         // get rid of any nodes that serve no purpose
         pruneUnusedNodes(model, nodes, referenced);
 
+        // set the overall scale
+        model.setLocalScale(Float.parseFloat(props.getProperty("scale", "1")));
+
         return model;
     }
 
@@ -517,6 +526,65 @@ public class ModelDef
         return referenced.contains(node) || hasValidChildren;
     }
 
+    /** Merges meshes with the same attributes. */
+    protected void mergeEquivalentMeshes (
+        Model model, HashMap<String, Spatial> nodes, final HashSet<Spatial> referenced)
+    {
+        final HashMap<Object, ArrayList<ModelMesh>> meshes =
+            new HashMap<Object, ArrayList<ModelMesh>>();
+        new SpatialVisitor<ModelMesh>(ModelMesh.class) {
+            public void traverse (Spatial spatial) {
+                // cut out when we encounter referenced nodes
+                if (!referenced.contains(spatial)) {
+                    spatial.updateWorldVectors();
+                    super.traverse(spatial);
+                }
+            }
+            protected void visit (ModelMesh mesh) {
+                // make sure we don't try this with skinned meshes
+                if (mesh instanceof SkinMesh) {
+                    return;
+                }
+                Object key = mesh.getAttributeKey();
+                ArrayList<ModelMesh> list = meshes.get(key);
+                if (list == null) {
+                    meshes.put(key, list = new ArrayList<ModelMesh>());
+                }
+                list.add(mesh);
+            }
+        }.traverse(model);
+
+        for (ArrayList<ModelMesh> list : meshes.values()) {
+            // the first in the list becomes the base
+            ModelMesh base = list.get(0);
+            flattenTransforms(base);
+            model.attachChild(base);
+
+            // the rest are merged with it
+            for (int ii = 1, nn = list.size(); ii < nn; ii++) {
+                ModelMesh mesh = list.get(ii);
+                flattenTransforms(mesh);
+                mesh.getParent().detachChild(mesh);
+                base.merge(mesh);
+            }
+
+            // update the model bound and recenter
+            base.updateModelBound();
+            base.centerVertices();
+        }
+    }
+
+    /** Transforms the mesh's vertices and normals into model coordinates. */
+    protected static void flattenTransforms (ModelMesh mesh)
+    {
+        GeomBatch batch = mesh.getBatch(0);
+        batch.getWorldCoords(batch.getVertexBuffer());
+        batch.getWorldNormals(batch.getNormalBuffer());
+        mesh.getLocalTranslation().zero();
+        mesh.getLocalRotation().loadIdentity();
+        mesh.getLocalScale().set(Vector3f.UNIT_XYZ);
+    }
+
     /** Converts a boxed Integer list to an unboxed int array. */
     protected static int[] toArray (ArrayList<Integer> list)
     {