blender/source/gameengine/SceneGraph/SG_ParentRelation.h
Benoit Bolsee 51b4145841 BGE Scenegraph and View frustrum culling improvement.
This commit contains a number of performance improvements for the
BGE in the Scenegraph (parent relation between objects in the
scene) and view frustrum culling.

The scenegraph improvement consists in avoiding position update
if the object has not moved since last update and the removal
of redundant updates and synchronization with the physics engine.

The view frustrum culling improvement consists in using the DBVT
broadphase facility of Bullet to build a tree of graphical objects
in the scene. The elements of the tree are Aabb boxes (Aligned 
Axis Bounding Boxes) enclosing the objects. This provides good
precision in closed and opened scenes. This new culling system
is enabled by default but just in case, it can be disabled with
a button in the World settings. There is no do_version in this
commit but it will be added before the 2.49 release. For now you
must manually enable the DBVT culling option in World settings
when you open an old file.

The above improvements speed up scenegraph and culling up to 5x.
However, this performance improvement is only visible when
you have hundreds or thousands of objects.

The main interest of the DBVT tree is to allow easy occlusion
culling and automatic LOD system. This will be the object of further
improvements.
2009-04-07 22:14:06 +00:00

135 lines
3.2 KiB
C++

/**
* @mainpage SG_ParentRelation
* @section
*
* This is an abstract interface class to the Scene Graph library.
* It allows you to specify how child nodes react to parent nodes.
* Normally a child will use it's parent's transforms to compute
* it's own global transforms. How this is performed depends on
* the type of relation. For example if the parent is a vertex
* parent to this child then the child should not inherit any
* rotation information from the parent. Or if the parent is a
* 'slow parent' to this child then the child should react
* slowly to changes in the parent's position. The exact relation
* is left for you to implement by filling out this interface
* with concrete examples.
*
* There is exactly one SG_ParentRelation per SG_Node. Subclasses
* should not be value types and should be allocated on the heap.
*
* $Id$
*
* ***** BEGIN GPL LICENSE BLOCK *****
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
* All rights reserved.
*
* The Original Code is: all of this file.
*
* Contributor(s): none yet.
*
* ***** END GPL LICENSE BLOCK *****
*
*/
#ifndef __SG_ParentRelation_h
#define __SG_ParentRelation_h
class SG_Spatial;
class SG_ParentRelation {
public :
/**
* Update the childs local and global coordinates
* based upon the parents global coordinates.
* You must also handle the case when this node has no
* parent (parent == NULL). Usually you should just
* copy the local coordinates of the child to the
* world coordinates.
*/
virtual
bool
UpdateChildCoordinates(
SG_Spatial * child,
const SG_Spatial * parent,
bool& parentUpdated
) = 0;
virtual
~SG_ParentRelation(
){
};
/**
* You must provide a way of duplicating an
* instance of an SG_ParentRelation. This should
* return a pointer to a new duplicate allocated
* on the heap. Responsibilty for deleting the
* duplicate resides with the caller of this method.
*/
virtual
SG_ParentRelation *
NewCopy(
) = 0;
/**
* Vertex Parent Relation are special: they don't propagate rotation
*/
virtual
bool
IsVertexRelation(
) {
return false;
}
/**
* Need this to see if we are able to adjust time-offset from the python api
*/
virtual
bool
IsSlowRelation(
) {
return false;
}
protected :
/**
* Protected constructors
* this class is not meant to be instantiated.
*/
SG_ParentRelation(
) {
};
/**
* Copy construction should not be implemented
*/
SG_ParentRelation(
const SG_ParentRelation &
);
};
#endif