bullet: improve performance of adding geometry to BulletTriangleMesh

dtool/src/parser-inc/btBulletDynamicsCommon.h

@@ -76,6 +76,7 @@ class btStaticPlaneShape;
 class btStridingMeshInterface;
 class btTransform;
 class btTranslationalLimitMotor;
+class btTriangleIndexVertexArray;
 class btTriangleMesh;
 class btTypedConstraint;
 class btTypedObject;

panda/src/bullet/bulletSoftBodyNode.cxx

@@ -197,7 +197,7 @@ transform_changed() {
       _soft->scale(new_scale);
     }
 
-    _sync = ts;
+    _sync = move(ts);
   }
 }
 

panda/src/bullet/bulletTriangleMesh.I

@@ -14,19 +14,9 @@
 /**
  *
  */
-INLINE BulletTriangleMesh::
-~BulletTriangleMesh() {
-
-  delete _mesh;
-}
-
-/**
- *
- */
-btTriangleMesh *BulletTriangleMesh::
+INLINE btStridingMeshInterface *BulletTriangleMesh::
 ptr() const {
-
-  return _mesh;
+  return (btStridingMeshInterface *)&_mesh;
 }
 
 /**
@@ -34,7 +24,6 @@ ptr() const {
  */
 INLINE ostream &
 operator << (ostream &out, const BulletTriangleMesh &obj) {
-
   obj.output(out);
   return out;
 }

panda/src/bullet/bulletTriangleMesh.cxx

@@ -23,150 +23,231 @@ TypeHandle BulletTriangleMesh::_type_handle;
  *
  */
 BulletTriangleMesh::
-BulletTriangleMesh() {
-
-  _mesh = new btTriangleMesh();
+BulletTriangleMesh()
+ : _welding_distance(0) {
+  btIndexedMesh mesh;
+  mesh.m_numTriangles = 0;
+  mesh.m_numVertices = 0;
+  mesh.m_indexType = PHY_INTEGER;
+  mesh.m_triangleIndexBase = nullptr;
+  mesh.m_triangleIndexStride = 3 * sizeof(int);
+  mesh.m_vertexBase = nullptr;
+  mesh.m_vertexStride = sizeof(btVector3);
+  _mesh.addIndexedMesh(mesh);
 }
 
 /**
- *
+ * Returns the number of triangles in this triangle mesh.
  */
 int BulletTriangleMesh::
 get_num_triangles() const {
-
-  return _mesh->getNumTriangles();
+  return _indices.size() / 3;
 }
 
 /**
- *
+ * Used to reserve memory in anticipation of the given amount of vertices and
+ * indices being added to the triangle mesh.  This is useful if you are about
+ * to call add_triangle() many times, to prevent unnecessary reallocations.
  */
 void BulletTriangleMesh::
 preallocate(int num_verts, int num_indices) {
-
-  _mesh->preallocateVertices(num_verts);
-  _mesh->preallocateIndices(num_indices);
+  _vertices.reserve(num_verts);
+  _indices.reserve(num_indices);
 }
 
 /**
+ * Adds a triangle with the indicated coordinates.
  *
+ * If remove_duplicate_vertices is true, it will make sure that it does not
+ * add duplicate vertices if they already exist in the triangle mesh, within
+ * the tolerance specified by set_welding_distance().  This comes at a
+ * significant performance cost, especially for large meshes.
  */
 void BulletTriangleMesh::
 add_triangle(const LPoint3 &p0, const LPoint3 &p1, const LPoint3 &p2, bool remove_duplicate_vertices) {
-
   nassertv(!p0.is_nan());
   nassertv(!p1.is_nan());
   nassertv(!p2.is_nan());
 
-  _mesh->addTriangle(
-    LVecBase3_to_btVector3(p0),
-    LVecBase3_to_btVector3(p1),
-    LVecBase3_to_btVector3(p2),
-    remove_duplicate_vertices);
+  btIndexedMesh &mesh = _mesh.getIndexedMeshArray()[0];
+  mesh.m_numTriangles++;
+
+  if (!remove_duplicate_vertices) {
+    unsigned int index = _vertices.size();
+    _indices.push_back(index++);
+    _indices.push_back(index++);
+    _indices.push_back(index++);
+
+    _vertices.push_back(LVecBase3_to_btVector3(p0));
+    _vertices.push_back(LVecBase3_to_btVector3(p1));
+    _vertices.push_back(LVecBase3_to_btVector3(p2));
+    mesh.m_numVertices += 3;
+    mesh.m_vertexBase = (unsigned char*)&_vertices[0];
+  } else {
+    _indices.push_back(find_or_add_vertex(p0));
+    _indices.push_back(find_or_add_vertex(p1));
+    _indices.push_back(find_or_add_vertex(p2));
+  }
+
+  mesh.m_triangleIndexBase = (unsigned char *)&_indices[0];
 }
 
 /**
+ * Sets the square of the distance at which vertices will be merged
+ * together when adding geometry with remove_duplicate_vertices set to true.
  *
+ * The default is 0, meaning vertices will only be merged if they have the
+ * exact same position.
  */
 void BulletTriangleMesh::
 set_welding_distance(PN_stdfloat distance) {
-
-  _mesh->m_weldingThreshold = distance;
+  _welding_distance = distance;
 }
 
 /**
- *
+ * Returns the value previously set with set_welding_distance(), or the
+ * value of 0 if none was set.
  */
 PN_stdfloat BulletTriangleMesh::
 get_welding_distance() const {
-
-  return _mesh->m_weldingThreshold;
+  return _welding_distance;
 }
 
 /**
+ * Adds the geometry from the indicated Geom from the triangle mesh.  This is
+ * a one-time copy operation, and future updates to the Geom will not be
+ * reflected.
  *
+ * If remove_duplicate_vertices is true, it will make sure that it does not
+ * add duplicate vertices if they already exist in the triangle mesh, within
+ * the tolerance specified by set_welding_distance().  This comes at a
+ * significant performance cost, especially for large meshes.
  */
 void BulletTriangleMesh::
 add_geom(const Geom *geom, bool remove_duplicate_vertices, const TransformState *ts) {
-
   nassertv(geom);
   nassertv(ts);
 
-  LMatrix4 m = ts->get_mat();
-
-  // Collect points
-  pvector<LPoint3> points;
-
   CPT(GeomVertexData) vdata = geom->get_vertex_data();
+  size_t num_vertices = vdata->get_num_rows();
   GeomVertexReader reader = GeomVertexReader(vdata, InternalName::get_vertex());
 
-  while (!reader.is_at_end()) {
-    points.push_back(m.xform_point(reader.get_data3()));
-  }
+  btIndexedMesh &mesh = _mesh.getIndexedMeshArray()[0];
 
-  // Convert points
-  btVector3 *vertices = new btVector3[points.size()];
+  if (!remove_duplicate_vertices) {
+    // Fast path: directly copy the vertices and indices.
+    mesh.m_numVertices += num_vertices;
+    unsigned int index_offset = _vertices.size();
+    _vertices.reserve(_vertices.size() + num_vertices);
 
-  int i = 0;
-  pvector<LPoint3>::const_iterator it;
-  for (it=points.begin(); it!=points.end(); it++) {
-    LPoint3 v = *it;
-    vertices[i] = LVecBase3_to_btVector3(v);
-    i++;
-  }
+    if (ts->is_identity()) {
+      while (!reader.is_at_end()) {
+        _vertices.push_back(LVecBase3_to_btVector3(reader.get_data3()));
+      }
+    } else {
+      LMatrix4 m = ts->get_mat();
+      while (!reader.is_at_end()) {
+        _vertices.push_back(LVecBase3_to_btVector3(m.xform_point(reader.get_data3())));
+      }
+    }
 
-  // Add triangles
-  for (int k=0; k<geom->get_num_primitives(); k++) {
+    for (int k = 0; k < geom->get_num_primitives(); ++k) {
+      CPT(GeomPrimitive) prim = geom->get_primitive(k);
+      prim = prim->decompose();
 
-    CPT(GeomPrimitive) prim = geom->get_primitive(k);
-    prim = prim->decompose();
+      if (prim->is_of_type(GeomTriangles::get_class_type())) {
+        int num_vertices = prim->get_num_vertices();
+        _indices.reserve(_indices.size() + num_vertices);
+        mesh.m_numTriangles += num_vertices / 3;
 
-    for (int l=0; l<prim->get_num_primitives(); l++) {
+        GeomVertexReader index(prim->get_vertices(), 0);
+        while (!index.is_at_end()) {
+          _indices.push_back(index_offset + index.get_data1i());
+        }
+      }
+    }
 
-      int s = prim->get_primitive_start(l);
-      int e = prim->get_primitive_end(l);
+  } else {
+    // Collect points
+    pvector<LPoint3> points;
+    points.reserve(_vertices.size() + num_vertices);
 
-      nassertv(e - s == 3);
+    if (ts->is_identity()) {
+      while (!reader.is_at_end()) {
+        points.push_back(reader.get_data3());
+      }
+    } else {
+      LMatrix4 m = ts->get_mat();
+      while (!reader.is_at_end()) {
+        points.push_back(m.xform_point(reader.get_data3()));
+      }
+    }
 
-      btVector3 v0 = vertices[prim->get_vertex(s)];
-      btVector3 v1 = vertices[prim->get_vertex(s+1)];
-      btVector3 v2 = vertices[prim->get_vertex(s+2)];
+    // Add triangles
+    for (int k = 0; k < geom->get_num_primitives(); ++k) {
+      CPT(GeomPrimitive) prim = geom->get_primitive(k);
+      prim = prim->decompose();
 
-      _mesh->addTriangle(v0, v1, v2, remove_duplicate_vertices);
+      if (prim->is_of_type(GeomTriangles::get_class_type())) {
+        int num_vertices = prim->get_num_vertices();
+        _indices.reserve(_indices.size() + num_vertices);
+        mesh.m_numTriangles += num_vertices / 3;
+
+        GeomVertexReader index(prim->get_vertices(), 0);
+        while (!index.is_at_end()) {
+          _indices.push_back(find_or_add_vertex(points[index.get_data1i()]));
+        }
+      }
     }
   }
 
-  delete [] vertices;
+  // Reset the pointers, since the vectors may have been reallocated.
+  mesh.m_vertexBase = (unsigned char*)&_vertices[0];
+  mesh.m_triangleIndexBase = (unsigned char *)&_indices[0];
 }
 
 /**
+ * Adds triangle information from an array of points and indices referring to
+ * these points.  This is more efficient than adding triangles one at a time.
  *
+ * If remove_duplicate_vertices is true, it will make sure that it does not
+ * add duplicate vertices if they already exist in the triangle mesh, within
+ * the tolerance specified by set_welding_distance().  This comes at a
+ * significant performance cost, especially for large meshes.
  */
 void BulletTriangleMesh::
 add_array(const PTA_LVecBase3 &points, const PTA_int &indices, bool remove_duplicate_vertices) {
+  btIndexedMesh &mesh = _mesh.getIndexedMeshArray()[0];
 
-  // Convert vertices
-  btVector3 *vertices = new btVector3[points.size()];
+  _indices.reserve(_indices.size() + indices.size());
 
-  int i = 0;
-  PTA_LVecBase3::const_iterator it;
-  for (it=points.begin(); it!=points.end(); it++) {
-    LVecBase3 v = *it;
-    vertices[i] = LVecBase3_to_btVector3(v);
-    i++;
+  if (!remove_duplicate_vertices) {
+    unsigned int index_offset = _vertices.size();
+    for (size_t i = 0; i < indices.size(); ++i) {
+      _indices.push_back(index_offset + indices[i]);
+    }
+
+    _vertices.reserve(_vertices.size() + points.size());
+    for (size_t i = 0; i < points.size(); ++i) {
+      _vertices.push_back(LVecBase3_to_btVector3(points[i]));
+    }
+
+    mesh.m_numVertices += points.size();
+
+  } else {
+    // Add the points one by one.
+    _indices.reserve(_indices.size() + indices.size());
+    for (size_t i = 0; i < indices.size(); ++i) {
+      LVecBase3 p = points[indices[i]];
+      _indices.push_back(find_or_add_vertex(p));
+    }
   }
 
-  // Add triangles
-  int j = 0;
-  while (j+2 < (int)indices.size()) {
+  mesh.m_numTriangles += indices.size() / 3;
 
-    btVector3 v0 = vertices[indices[j++]];
-    btVector3 v1 = vertices[indices[j++]];
-    btVector3 v2 = vertices[indices[j++]];
-
-    _mesh->addTriangle(v0, v1, v2, remove_duplicate_vertices);
-  }
-
-  delete [] vertices;
+  // Reset the pointers, since the vectors may have been reallocated.
+  mesh.m_vertexBase = (unsigned char*)&_vertices[0];
+  mesh.m_triangleIndexBase = (unsigned char *)&_indices[0];
 }
 
 /**
@@ -174,8 +255,7 @@ add_array(const PTA_LVecBase3 &points, const PTA_int &indices, bool remove_dupli
  */
 void BulletTriangleMesh::
 output(ostream &out) const {
-
-  out << get_type() << ", " << _mesh->getNumTriangles();
+  out << get_type() << ", " << get_num_triangles() << " triangles";
 }
 
 /**
@@ -183,19 +263,39 @@ output(ostream &out) const {
  */
 void BulletTriangleMesh::
 write(ostream &out, int indent_level) const {
-
   indent(out, indent_level) << get_type() << ":" << endl;
 
-  IndexedMeshArray& array = _mesh->getIndexedMeshArray();
-  for (int i=0; i < array.size(); i++) {
+  const IndexedMeshArray &array = _mesh.getIndexedMeshArray();
+  for (size_t i = 0; i < array.size(); ++i) {
     indent(out, indent_level + 2) << "IndexedMesh " << i << ":" << endl;
-    btIndexedMesh meshPart = array.at(i);
-
-    indent(out, indent_level + 4) << "num triangles:" << meshPart.m_numTriangles << endl;
-    indent(out, indent_level + 4) << "num vertices:" << meshPart.m_numVertices << endl;
+    const btIndexedMesh &mesh = array[0];
+    indent(out, indent_level + 4) << "num triangles:" << mesh.m_numTriangles << endl;
+    indent(out, indent_level + 4) << "num vertices:" << mesh.m_numVertices << endl;
   }
 }
 
+/**
+ * Finds the indicated vertex and returns its index.  If it was not found,
+ * adds it as a new vertex and returns its index.
+ */
+unsigned int BulletTriangleMesh::
+find_or_add_vertex(const LVecBase3 &p) {
+  btVector3 vertex = LVecBase3_to_btVector3(p);
+
+  for (unsigned int i = 0; i < _vertices.size(); ++i) {
+    if ((_vertices[i] - vertex).length2() <= _welding_distance) {
+      return i;
+    }
+  }
+
+  _vertices.push_back(vertex);
+
+  btIndexedMesh &mesh = _mesh.getIndexedMeshArray()[0];
+  mesh.m_numVertices++;
+  mesh.m_vertexBase = (unsigned char*)&_vertices[0];
+  return _vertices.size() - 1;
+}
+
 /**
  * Tells the BamReader how to create objects of type BulletTriangleMesh.
  */
@@ -215,7 +315,7 @@ write_datagram(BamWriter *manager, Datagram &dg) {
   // In case we ever want to represent more than 1 indexed mesh.
   dg.add_int32(1);
 
-  btIndexedMesh &mesh = _mesh->getIndexedMeshArray()[0];
+  btIndexedMesh &mesh = _mesh.getIndexedMeshArray()[0];
   dg.add_int32(mesh.m_numVertices);
   dg.add_int32(mesh.m_numTriangles);
 
@@ -238,22 +338,12 @@ write_datagram(BamWriter *manager, Datagram &dg) {
   const unsigned char *iptr = mesh.m_triangleIndexBase;
   nassertv(iptr != NULL || mesh.m_numTriangles == 0);
 
-  if (_mesh->getUse32bitIndices()) {
-    for (int i = 0; i < mesh.m_numTriangles; ++i) {
-      int *triangle = (int *)iptr;
-      dg.add_int32(triangle[0]);
-      dg.add_int32(triangle[1]);
-      dg.add_int32(triangle[2]);
-      iptr += mesh.m_triangleIndexStride;
-    }
-  } else {
-    for (int i = 0; i < mesh.m_numTriangles; ++i) {
-      short int *triangle = (short int *)iptr;
-      dg.add_int32(triangle[0]);
-      dg.add_int32(triangle[1]);
-      dg.add_int32(triangle[2]);
-      iptr += mesh.m_triangleIndexStride;
-    }
+  for (int i = 0; i < mesh.m_numTriangles; ++i) {
+    int *triangle = (int *)iptr;
+    dg.add_int32(triangle[0]);
+    dg.add_int32(triangle[1]);
+    dg.add_int32(triangle[2]);
+    iptr += mesh.m_triangleIndexStride;
   }
 }
 
@@ -287,23 +377,26 @@ fillin(DatagramIterator &scan, BamReader *manager) {
   int num_triangles = scan.get_int32();
   nassertv(scan.get_bool() == true);
 
+  btIndexedMesh &mesh = _mesh.getIndexedMeshArray()[0];
+  mesh.m_numVertices = num_vertices;
+  mesh.m_numTriangles = num_triangles;
+
   // Read and add the vertices.
-  _mesh->preallocateVertices(num_vertices);
+  _vertices.clear();
+  _vertices.reserve(num_vertices);
   for (int i = 0; i < num_vertices; ++i) {
     PN_stdfloat x = scan.get_stdfloat();
     PN_stdfloat y = scan.get_stdfloat();
     PN_stdfloat z = scan.get_stdfloat();
-    _mesh->findOrAddVertex(btVector3(x, y, z), false);
+    _vertices.push_back(btVector3(x, y, z));
   }
 
   // Now read and add the indices.
-  int num_indices = num_triangles * 3;
-  _mesh->preallocateIndices(num_indices);
-  for (int i = 0; i < num_indices; ++i) {
-    _mesh->addIndex(scan.get_int32());
-  }
+  size_t num_indices = (size_t)num_triangles * 3;
+  _indices.resize(num_indices);
+  scan.extract_bytes((unsigned char *)&_indices[0], num_indices * sizeof(int));
 
-  // Since we manually added the vertices individually, we have to update the
-  // triangle count appropriately.
-  _mesh->getIndexedMeshArray()[0].m_numTriangles = num_triangles;
+  // Reset the pointers, since the vectors may have been reallocated.
+  mesh.m_vertexBase = (unsigned char*)&_vertices[0];
+  mesh.m_triangleIndexBase = (unsigned char *)&_indices[0];
 }

panda/src/bullet/bulletTriangleMesh.h

@@ -30,10 +30,9 @@
  *
  */
 class EXPCL_PANDABULLET BulletTriangleMesh : public TypedWritableReferenceCount {
-
 PUBLISHED:
   BulletTriangleMesh();
-  INLINE ~BulletTriangleMesh();
+  ~BulletTriangleMesh() DEFAULT_DTOR;
 
   void add_triangle(const LPoint3 &p0,
                     const LPoint3 &p1,
@@ -59,10 +58,15 @@ PUBLISHED:
   MAKE_PROPERTY(welding_distance, get_welding_distance, set_welding_distance);
 
 public:
-  INLINE btTriangleMesh *ptr() const;
+  INLINE btStridingMeshInterface *ptr() const;
 
 private:
-  btTriangleMesh *_mesh;
+  unsigned int find_or_add_vertex(const LVecBase3 &p);
+
+  btTriangleIndexVertexArray _mesh;
+  btAlignedObjectArray<btVector3> _vertices;
+  btAlignedObjectArray<unsigned int> _indices;
+  PN_stdfloat _welding_distance;
 
 public:
   static void register_with_read_factory();

panda/src/bullet/bulletTriangleMeshShape.cxx

@@ -145,7 +145,7 @@ complete_pointers(TypedWritable **p_list, BamReader *manager) {
 
   _mesh = DCAST(BulletTriangleMesh, p_list[pi++]);
 
-  btTriangleMesh *mesh_ptr = _mesh->ptr();
+  btStridingMeshInterface *mesh_ptr = _mesh->ptr();
   nassertr(mesh_ptr != NULL, pi);
 
   if (_dynamic) {