SimGear: SGUpdateVisitor.hxx Source File

00001 /* -*-c++-*-
00002  *
00003  * Copyright (C) 2006-2009 Mathias Froehlich 
00004  *
00005  * This program is free software; you can redistribute it and/or
00006  * modify it under the terms of the GNU General Public License as
00007  * published by the Free Software Foundation; either version 2 of the
00008  * License, or (at your option) any later version.
00009  *
00010  * This program is distributed in the hope that it will be useful, but
00011  * WITHOUT ANY WARRANTY; without even the implied warranty of
00012  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013  * General Public License for more details.
00014  *
00015  * You should have received a copy of the GNU General Public License
00016  * along with this program; if not, write to the Free Software
00017  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
00018  * MA 02110-1301, USA.
00019  *
00020  */
00021 
00022 #ifndef SG_SCENE_UPDATEVISITOR_HXX
00023 #define SG_SCENE_UPDATEVISITOR_HXX
00024 
00025 #include <osg/NodeVisitor>
00026 #include <osg/PagedLOD>
00027 #include <osgUtil/UpdateVisitor>
00028 
00029 #include "simgear/math/SGMath.hxx"
00030 
00031 class SGUpdateVisitor : public osgUtil::UpdateVisitor {
00032 public:
00033   SGUpdateVisitor() :
00034     mVisibility(-1)
00035   {
00036     setTraversalMode(osg::NodeVisitor::TRAVERSE_ACTIVE_CHILDREN);
00037     setVisibility(10000);
00038   }
00039   void setViewData(const SGVec3d& globalEyePos,
00040                    const SGQuatd& globalViewOrientation)
00041   {
00042     mGlobalGeodEyePos = SGGeod::fromCart(globalEyePos);
00043     _currentEyePos = toOsg(globalEyePos);
00044     mGlobalEyePos = globalEyePos;
00045     mGlobalViewOr = globalViewOrientation;
00046     mGlobalHorizLocalOr = SGQuatd::fromLonLat(mGlobalGeodEyePos);
00047     mHorizLocalNorth = mGlobalHorizLocalOr.backTransform(SGVec3d(1, 0, 0));
00048     mHorizLocalEast = mGlobalHorizLocalOr.backTransform(SGVec3d(0, 1, 0));
00049     mHorizLocalDown = mGlobalHorizLocalOr.backTransform(SGVec3d(0, 0, 1));
00050   }
00051 
00052   void setVisibility(double visibility)
00053   {
00054     if (mVisibility == visibility)
00055       return;
00056     mVisibility = visibility;
00057     mSqrVisibility = visibility*visibility;
00058 
00059     double m_log01 = -log( 0.01 );
00060     double sqrt_m_log01 = sqrt( m_log01 );
00061     double fog_exp_density = m_log01 / visibility;
00062     double fog_exp2_density = sqrt_m_log01 / visibility;
00063     double ground_exp2_punch_through = sqrt_m_log01 / (visibility * 1.5);
00064     double rwy_exp2_punch_through, taxi_exp2_punch_through;
00065     if ( visibility < 8000 ) {
00066       rwy_exp2_punch_through = sqrt_m_log01 / (visibility * 2.5);
00067       taxi_exp2_punch_through = sqrt_m_log01 / (visibility * 1.5);
00068     } else {
00069       rwy_exp2_punch_through = sqrt_m_log01 / ( 8000 * 2.5 );
00070       taxi_exp2_punch_through = sqrt_m_log01 / ( 8000 * 1.5 );
00071     }
00072     
00073     mFogExpDensity = fog_exp_density;
00074     mFogExp2Density = fog_exp2_density;
00075     mRunwayFogExp2Density = rwy_exp2_punch_through;
00076     mTaxiFogExp2Density = taxi_exp2_punch_through;
00077     mGroundLightsFogExp2Density = ground_exp2_punch_through;
00078   }
00079 
00080   double getVisibility() const
00081   { return mVisibility; }
00082   double getSqrVisibility() const
00083   { return mSqrVisibility; }
00084 
00085   double getFogExpDensity() const
00086   { return mFogExpDensity; }
00087   double getFogExp2Density() const
00088   { return mFogExp2Density; }
00089   double getRunwayFogExp2Density() const
00090   { return mRunwayFogExp2Density; }
00091   double getTaxiFogExp2Density() const
00092   { return mTaxiFogExp2Density; }
00093   double getGroundLightsFogExp2Density() const
00094   { return mGroundLightsFogExp2Density; }
00095 
00096   const SGVec3d& getGlobalEyePos() const
00097   { return mGlobalEyePos; }
00098   const SGGeod& getGeodEyePos() const
00099   { return mGlobalGeodEyePos; }
00100   const SGQuatd& getGlobalViewOr() const
00101   { return mGlobalViewOr; }
00102   const SGQuatd& getGlobalHorizLocalOr() const
00103   { return mGlobalViewOr; }
00104   const SGVec3d& getHorizLocalNorth() const
00105   { return mHorizLocalNorth; }
00106   const SGVec3d& getHorizLocalEast() const
00107   { return mHorizLocalEast; }
00108   const SGVec3d& getHorizLocalDown() const
00109   { return mHorizLocalDown; }
00110 
00111   void setLight(const SGVec3f& direction, const SGVec4f& ambient,
00112                 const SGVec4f& diffuse, const SGVec4f& specular,
00113                 const SGVec4f& fogColor, double sunAngleDeg)
00114   {
00115     mLightDirection = direction;
00116     mAmbientLight = ambient;
00117     mDiffuseLight = diffuse;
00118     mSpecularLight = specular;
00119     mFogColor = fogColor;
00120     mSunAngleDeg = sunAngleDeg;
00121   }
00122 
00123   const SGVec3f& getLightDirection() const
00124   { return mLightDirection; }
00125   const SGVec4f& getAmbientLight() const
00126   { return mAmbientLight; }
00127   const SGVec4f& getDiffuseLight() const
00128   { return mDiffuseLight; }
00129   const SGVec4f& getSpecularLight() const
00130   { return mSpecularLight; }
00131   const SGVec4f& getFogColor() const
00132   { return mFogColor; }
00133 
00134   double getSunAngleDeg() const
00135   { return mSunAngleDeg; }
00136 
00137   virtual void apply(osg::Node& node)
00138   {
00139     if (!needToEnterNode(node))
00140       return;
00141     osgUtil::UpdateVisitor::apply(node);
00142   }
00143   // To avoid expiry of LOD nodes that are in range and that are updated,
00144   // mark them with the last traversal number, even if they are culled away
00145   // by the cull frustum.
00146   virtual void apply(osg::PagedLOD& pagedLOD)
00147   {
00148     if (!needToEnterNode(pagedLOD))
00149       return;
00150     if (getFrameStamp())
00151       pagedLOD.setFrameNumberOfLastTraversal(getFrameStamp()->getFrameNumber());
00152     osgUtil::UpdateVisitor::apply(pagedLOD);
00153   }
00154   // To be able to traverse correctly only the active children, we need to
00155   // track the model view matrices during update.
00156   virtual void apply(osg::Transform& transform)
00157   {
00158     if (!needToEnterNode(transform))
00159       return;
00160     osg::Matrix matrix = _matrix;
00161     transform.computeLocalToWorldMatrix(_matrix, this);
00162     osgUtil::UpdateVisitor::apply(transform);
00163     _matrix = matrix;
00164   }
00165   virtual void apply(osg::Camera& camera)
00166   {
00167     if (!needToEnterNode(camera))
00168       return;
00169     if (camera.getReferenceFrame() == osg::Camera::ABSOLUTE_RF) {
00170       osg::Vec3d currentEyePos = _currentEyePos;
00171       _currentEyePos = osg::Vec3d(0, 0, 0);
00172       apply(static_cast<osg::Transform&>(camera));
00173       _currentEyePos = currentEyePos;
00174     } else {
00175       apply(static_cast<osg::Transform&>(camera));
00176     }
00177   }
00178   // Function to make the LOD traversal only enter that children that
00179   // are visible on the screen.
00180   virtual float getDistanceToViewPoint(const osg::Vec3& pos, bool) const
00181   { return (_currentEyePos - _matrix.preMult(osg::Vec3d(pos))).length(); }
00182 
00183 protected:
00184   bool needToEnterNode(const osg::Node& node) const
00185   {
00186     if (!node.isCullingActive())
00187       return true;
00188     return isSphereInRange(node.getBound());
00189   }
00190   bool isSphereInRange(const osg::BoundingSphere& sphere) const
00191   {
00192     if (!sphere.valid())
00193       return false;
00194     float maxDist = mVisibility + sphere._radius;
00195     osg::Vec3d center = _matrix.preMult(osg::Vec3d(sphere._center));
00196     return (_currentEyePos - center).length2() <= maxDist*maxDist;
00197   }
00198     
00199 private:
00200   osg::Matrix _matrix;
00201   osg::Vec3d _currentEyePos;
00202 
00203   SGGeod mGlobalGeodEyePos;
00204   SGVec3d mGlobalEyePos;
00205   SGQuatd mGlobalViewOr;
00206   SGQuatd mGlobalHorizLocalOr;
00207   SGVec3d mHorizLocalNorth;
00208   SGVec3d mHorizLocalEast;
00209   SGVec3d mHorizLocalDown;
00210 
00211   double mVisibility;
00212   double mSqrVisibility;
00213   double mFogExpDensity;
00214   double mFogExp2Density;
00215   double mRunwayFogExp2Density;
00216   double mTaxiFogExp2Density;
00217   double mGroundLightsFogExp2Density;
00218 
00219   SGVec3f mLightDirection;
00220   SGVec4f mAmbientLight;
00221   SGVec4f mDiffuseLight;
00222   SGVec4f mSpecularLight;
00223   SGVec4f mFogColor;
00224 
00225   double mSunAngleDeg;
00226 };
00227 
00228 #endif