Physics Simulation Forum

static btScalar gContactBreakingThreshold = 0.0f; // doesn't seem to have an effect though

void vtkBulletCollisionDetection::InitWorld()
{
   this->configuration = new btDefaultCollisionConfiguration();
   this->dispatcher = new btCollisionDispatcher(this->configuration);
   this->broadphase = new btSimpleBroadphase();

   this->world = new btCollisionWorld(this->dispatcher, this->broadphase, this->configuration);

   btGImpactCollisionAlgorithm::registerAlgorithm(this->dispatcher);
}

btRigidBody* vtkBulletCollisionDetection::CreateRigidBody(vtkPolyData *vtk_poly_data, vtkMatrix4x4 *vtk_matrix)
{
   int number_of_triangles;
   int number_of_points;
   int *triangles;
   btScalar *points;

   this->GetTriangleData(number_of_triangles, triangles, number_of_points, points, vtk_poly_data);

   btTriangleIndexVertexArray* bt_triangle_array = new btTriangleIndexVertexArray(number_of_triangles, triangles, 3 * sizeof(int), number_of_points, points, 3 * sizeof(btScalar));
   btGImpactMeshShape *bt_mesh_shape = new btGImpactMeshShape(bt_triangle_array);
   bt_mesh_shape->updateBound();

   btScalar matrix[15];
   this->GetMatrixData(matrix, vtk_matrix);

   btTransform bt_transform;
   bt_transform.setFromOpenGLMatrix(matrix);

   btRigidBody* bt_rigid_body = new btRigidBody(1.0, new btDefaultMotionState(bt_transform), bt_mesh_shape);
   bt_rigid_body->setContactProcessingThreshold(0.0); // this doesn't seem to help either

   return bt_rigid_body;
}

void vtkBulletCollisionDetection::AddActor(vtkActor *vtk_actor)
{
   btRigidBody* bt_rigid_body = this->CreateRigidBody(vtkPolyData::SafeDownCast(vtk_actor->GetMapper()->GetInput()), vtk_actor->GetMatrix());

   this->world->addCollisionObject(bt_rigid_body);

   this->actor_body_dictionary.push_back(ABPair(vtk_actor, bt_rigid_body));

   this->UpdateTransform(vtk_actor);
}

void vtkBulletCollisionDetection::UpdateTransform(vtkActor *vtk_actor)
{
   btRigidBody* bt_rigid_body;

   for(int i = 0; i < this->actor_body_dictionary.size(); i++)
   {
      ABPair pair = this->actor_body_dictionary[i];

      if(pair.first == vtk_actor)
      {
         bt_rigid_body = pair.second;

         break;
      }
   }

   btScalar matrix[15];
   this->GetMatrixData(matrix, vtk_actor->GetMatrix());

   btTransform bt_transform;
   bt_transform.setFromOpenGLMatrix(matrix);
   bt_rigid_body->setWorldTransform(bt_transform);
}

int vtkBulletCollisionDetection::CollisionQuery()
{
   this->world->performDiscreteCollisionDetection();

   int num_manifolds = this->world->getDispatcher()->getNumManifolds();
   if(num_manifolds == 0)
      return 0;

    int num_contacts = manifold->getNumContacts();

   return num_contacts;
}