108 lines
5.0 KiB
C++
108 lines
5.0 KiB
C++
/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield
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*
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* This library is open source and may be redistributed and/or modified under
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* the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
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* (at your option) any later version. The full license is in LICENSE file
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* included with this distribution, and on the openscenegraph.org website.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* OpenSceneGraph Public License for more details.
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*/
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#ifndef OSG_CLUSTERCULLINGCALLBACK
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#define OSG_CLUSTERCULLINGCALLBACK 1
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#include <osg/Drawable>
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#include <osg/Callback>
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namespace osg {
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/** @class ClusterCullingCallback
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@brief Implements cluster culling to cull back facing subgraphs and drawables. Derived from Drawable::CullCallback and osg::NodeCallback.
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This culling callback is intended to be attached to a node using the setCullCallback method. If the
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node is a drawable cull(osg::NodeVisitor*, osg::Drawable*, osg::State*) otherwise
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operator()(Node*, NodeVisitor*) will be called during the cull traversal.
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To decide whether the node (in case of a drawable) or its children (in case of any other node type) are
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to be culled depends on four parameters:
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- a control point,
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- a normal specified at the control point,
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- a deviation value representing the cosinus of an enclosed angle and
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- a radius describing a sphere around the control point.
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The node is culled if the following two conditions are fulfilled:
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- the distance between the current eye/view point to the control point is larger or equal to radius,
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- the cosinus of the enclosed angle between the normal and the vector from the control point to the eye/view point
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is smaller(!) than the specified deviation value (normally this value is negative meaning that the enclosed angle
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between the control point and the eye/view point is larger than the angle indirectly specified by the
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deviation value).
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@remark As the deviation is representing the cosine of an enclosed angle its value should be within the
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the interval [-1; 1]. A value of one will cull all nodes while a value of -1 will never cull a node.
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The deviation will normally have negative values because then the enclosed angle between the normal and the
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eye/view point is larger than 90 degrees (and therefore the eye sees the "back" from the control point).
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*/
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class OSG_EXPORT ClusterCullingCallback : public DrawableCullCallback, public NodeCallback
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{
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public:
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ClusterCullingCallback();
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ClusterCullingCallback(const ClusterCullingCallback& ccc,const CopyOp& copyop);
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ClusterCullingCallback(const osg::Vec3& controlPoint, const osg::Vec3& normal, float deviation, float radius=-1.0f);
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ClusterCullingCallback(const osg::Drawable* drawable);
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META_Object(osg,ClusterCullingCallback);
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virtual NodeCallback* asNodeCallback() { return osg::NodeCallback::asNodeCallback(); }
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virtual const NodeCallback* asNodeCallback() const { return osg::NodeCallback::asNodeCallback(); }
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virtual DrawableCullCallback* asDrawableCullCallback() { return osg::DrawableCullCallback::asDrawableCullCallback(); }
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virtual const DrawableCullCallback* asDrawableCullCallback() const { return osg::DrawableCullCallback::asDrawableCullCallback(); }
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// use the NodeCallbacks implementation of run.
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virtual bool run(osg::Object* object, osg::Object* data) { return NodeCallback::run(object, data); }
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/** Computes the control point, normal, and deviation from the
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* given drawable contents. */
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void computeFrom(const osg::Drawable* drawable);
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/** Transform the ClusterCullingCallback's positional members to a new coordinate frame.*/
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void transform(const osg::Matrixd& matrix);
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void set(const osg::Vec3& controlPoint, const osg::Vec3& normal, float deviation, float radius);
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void setControlPoint(const osg::Vec3& controlPoint) { _controlPoint = controlPoint; }
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const osg::Vec3& getControlPoint() const { return _controlPoint; }
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void setNormal(const osg::Vec3& normal) { _normal = normal; }
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const osg::Vec3& getNormal() const { return _normal; }
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void setRadius(float radius) { _radius = radius; }
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float getRadius() const { return _radius; }
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void setDeviation(float deviation) { _deviation = deviation; }
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float getDeviation() const { return _deviation; }
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virtual bool cull(osg::NodeVisitor*, osg::Drawable*, osg::State*) const;
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/** Callback method called by the NodeVisitor when visiting a node.*/
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virtual void operator()(Node* node, NodeVisitor* nv);
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protected:
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virtual ~ClusterCullingCallback() {}
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osg::Vec3 _controlPoint;
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osg::Vec3 _normal;
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float _radius;
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float _deviation;
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};
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}
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#endif
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