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/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield
*
* This library is open source and may be redistributed and/or modified under
* the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
* (at your option) any later version. The full license is in LICENSE file
* included with this distribution, and on the openscenegraph.org website.
*
* This library 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
* OpenSceneGraph Public License for more details.
*/
#ifndef OSG_CLUSTERCULLINGCALLBACK
#define OSG_CLUSTERCULLINGCALLBACK 1
#include <osg/Drawable>
#include <osg/Callback>
namespace osg {
/** @class ClusterCullingCallback
@brief Implements cluster culling to cull back facing subgraphs and drawables. Derived from Drawable::CullCallback and osg::NodeCallback.
This culling callback is intended to be attached to a node using the setCullCallback method. If the
node is a drawable cull(osg::NodeVisitor*, osg::Drawable*, osg::State*) otherwise
operator()(Node*, NodeVisitor*) will be called during the cull traversal.
To decide whether the node (in case of a drawable) or its children (in case of any other node type) are
to be culled depends on four parameters:
- a control point,
- a normal specified at the control point,
- a deviation value representing the cosinus of an enclosed angle and
- a radius describing a sphere around the control point.
The node is culled if the following two conditions are fulfilled:
- the distance between the current eye/view point to the control point is larger or equal to radius,
- the cosinus of the enclosed angle between the normal and the vector from the control point to the eye/view point
is smaller(!) than the specified deviation value (normally this value is negative meaning that the enclosed angle
between the control point and the eye/view point is larger than the angle indirectly specified by the
deviation value).
@remark As the deviation is representing the cosine of an enclosed angle its value should be within the
the interval [-1; 1]. A value of one will cull all nodes while a value of -1 will never cull a node.
The deviation will normally have negative values because then the enclosed angle between the normal and the
eye/view point is larger than 90 degrees (and therefore the eye sees the "back" from the control point).
*/
class OSG_EXPORT ClusterCullingCallback : public DrawableCullCallback, public NodeCallback
{
public:
ClusterCullingCallback();
ClusterCullingCallback(const ClusterCullingCallback& ccc,const CopyOp& copyop);
ClusterCullingCallback(const osg::Vec3& controlPoint, const osg::Vec3& normal, float deviation, float radius=-1.0f);
ClusterCullingCallback(const osg::Drawable* drawable);
META_Object(osg,ClusterCullingCallback);
virtual NodeCallback* asNodeCallback() { return osg::NodeCallback::asNodeCallback(); }
virtual const NodeCallback* asNodeCallback() const { return osg::NodeCallback::asNodeCallback(); }
virtual DrawableCullCallback* asDrawableCullCallback() { return osg::DrawableCullCallback::asDrawableCullCallback(); }
virtual const DrawableCullCallback* asDrawableCullCallback() const { return osg::DrawableCullCallback::asDrawableCullCallback(); }
// use the NodeCallbacks implementation of run.
virtual bool run(osg::Object* object, osg::Object* data) { return NodeCallback::run(object, data); }
/** Computes the control point, normal, and deviation from the
* given drawable contents. */
void computeFrom(const osg::Drawable* drawable);
/** Transform the ClusterCullingCallback's positional members to a new coordinate frame.*/
void transform(const osg::Matrixd& matrix);
void set(const osg::Vec3& controlPoint, const osg::Vec3& normal, float deviation, float radius);
void setControlPoint(const osg::Vec3& controlPoint) { _controlPoint = controlPoint; }
const osg::Vec3& getControlPoint() const { return _controlPoint; }
void setNormal(const osg::Vec3& normal) { _normal = normal; }
const osg::Vec3& getNormal() const { return _normal; }
void setRadius(float radius) { _radius = radius; }
float getRadius() const { return _radius; }
void setDeviation(float deviation) { _deviation = deviation; }
float getDeviation() const { return _deviation; }
virtual bool cull(osg::NodeVisitor*, osg::Drawable*, osg::State*) const;
/** Callback method called by the NodeVisitor when visiting a node.*/
virtual void operator()(Node* node, NodeVisitor* nv);
protected:
virtual ~ClusterCullingCallback() {}
osg::Vec3 _controlPoint;
osg::Vec3 _normal;
float _radius;
float _deviation;
};
}
#endif
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