1 // groundcache.hxx -- carries a small subset of the scenegraph near the vehicle
3 // Written by Mathias Froehlich, started Nov 2004.
5 // Copyright (C) 2004 Mathias Froehlich - Mathias.Froehlich@web.de
7 // This program is free software; you can redistribute it and/or
8 // modify it under the terms of the GNU General Public License as
9 // published by the Free Software Foundation; either version 2 of the
10 // License, or (at your option) any later version.
12 // This program is distributed in the hope that it will be useful, but
13 // WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 // General Public License for more details.
17 // You should have received a copy of the GNU General Public License
18 // along with this program; if not, write to the Free Software
19 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
23 #ifndef _GROUNDCACHE_HXX
24 #define _GROUNDCACHE_HXX
26 #include <simgear/compiler.h>
27 #include <simgear/constants.h>
28 #include <simgear/math/SGMath.hxx>
29 #include <simgear/math/SGGeometry.hxx>
30 #include <simgear/bvh/BVHNode.hxx>
31 #include <simgear/structure/SGSharedPtr.hxx>
33 // #define GROUNDCACHE_DEBUG
34 #ifdef GROUNDCACHE_DEBUG
36 #include <osg/ref_ptr>
37 #include <simgear/timing/timestamp.hxx>
41 class BVHLineGeometry;
50 //////////////////////////////////////////////////////////////////////////
51 // Ground handling routines
52 //////////////////////////////////////////////////////////////////////////
54 // Prepare the ground cache for the wgs84 position pt_*.
55 // That is take all vertices in the ball with radius rad around the
56 // position given by the pt_* and store them in a local scene graph.
57 bool prepare_ground_cache(double startSimTime, double endSimTime,
58 const SGVec3d& pt, double rad);
60 // Returns true if the cache is valid.
61 // Also the reference time, point and radius values where the cache
62 // is valid for are returned.
63 bool is_valid(double& ref_time, SGVec3d& pt, double& rad);
65 // Returns the unit down vector at the ground cache
66 const SGVec3d& get_down() const
69 // The time offset that originates from a simtime different than zero
70 // at initialization time of the fdm.
71 double get_cache_time_offset() const
72 { return cache_time_offset; }
73 void set_cache_time_offset(double time_offset)
74 { cache_time_offset = time_offset; }
76 bool get_body(double t, SGMatrixd& bodyToWorld, SGVec3d& linearVel,
77 SGVec3d& angularVel, simgear::BVHNode::Id id);
79 // Return the nearest catapult to the given point
80 // pt in wgs84 coordinates.
81 double get_cat(double t, const SGVec3d& pt,
82 SGVec3d end[2], SGVec3d vel[2]);
85 // Return the altitude above ground below the wgs84 point pt
86 // Search for highest triangle not higher than pt + max_altoff.
87 // Return ground properties like the maximum load
88 // this kind kind of ground can carry, the friction factor between
89 // 0 and 1 which can be used to model lower friction with wet runways.
90 bool get_agl(double t, const SGVec3d& pt, SGVec3d& contact,
91 SGVec3d& normal, SGVec3d& linearVel, SGVec3d& angularVel,
92 simgear::BVHNode::Id& id,
93 const simgear::BVHMaterial*& material);
95 bool get_nearest(double t, const SGVec3d& pt, double maxDist,
96 SGVec3d& contact, SGVec3d& linearVel, SGVec3d& angularVel,
97 simgear::BVHNode::Id& id,
98 const simgear::BVHMaterial*& material);
100 // Return 1 if the hook intersects with a wire.
101 // That test is done by checking if the quad spanned by the points pt*
102 // intersects with the line representing the wire.
103 // If the wire is caught, the cache will trace this wires endpoints until
104 // the FDM calls release_wire().
105 bool caught_wire(double t, const SGVec3d pt[4]);
107 // Return the location and speed of the wire endpoints.
108 bool get_wire_ends(double t, SGVec3d end[2], SGVec3d vel[2]);
110 // Tell the cache code that it does no longer need to care for
111 // the wire end position.
112 void release_wire(void);
117 class CatapultFinder;
118 class WireIntersector;
121 // Approximate ground radius.
122 // In case the aircraft is too high above ground.
124 // the simgear material reference, contains friction coeficients ...
125 const simgear::BVHMaterial* _material;
126 // The time reference for later call to intersection test routines.
127 // Is required since we will have moving triangles in carriers.
128 double cache_ref_time;
129 // The time the cache was initialized.
130 double cache_time_offset;
131 // The wire to track.
132 const simgear::BVHLineGeometry* _wire;
134 // The point and radius where the cache is built around.
135 // That are the arguments that were given to prepare_ground_cache.
136 SGVec3d reference_wgs84_point;
137 double reference_vehicle_radius;
141 SGSharedPtr<simgear::BVHNode> _localBvhTree;
143 #ifdef GROUNDCACHE_DEBUG
144 SGTimeStamp _lookupTime;
145 unsigned _lookupCount;
146 SGTimeStamp _buildTime;
147 unsigned _buildCount;
149 osg::ref_ptr<osg::Group> _group;