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
27 #include <osg/ref_ptr>
29 #include <simgear/compiler.h>
30 #include <simgear/constants.h>
31 #include <simgear/math/SGMath.hxx>
32 #include <simgear/math/SGGeometry.hxx>
33 #include <simgear/scene/bvh/BVHNode.hxx>
34 #include <simgear/structure/SGSharedPtr.hxx>
38 class BVHLineGeometry;
46 //////////////////////////////////////////////////////////////////////////
47 // Ground handling routines
48 //////////////////////////////////////////////////////////////////////////
50 // Prepare the ground cache for the wgs84 position pt_*.
51 // That is take all vertices in the ball with radius rad around the
52 // position given by the pt_* and store them in a local scene graph.
53 bool prepare_ground_cache(double startSimTime, double endSimTime,
54 const SGVec3d& pt, double rad);
56 // Returns true if the cache is valid.
57 // Also the reference time, point and radius values where the cache
58 // is valid for are returned.
59 bool is_valid(double& ref_time, SGVec3d& pt, double& rad);
61 // Returns the unit down vector at the ground cache
62 const SGVec3d& get_down() const
65 double get_cache_time_offset() const
66 { return cache_time_offset; }
67 void set_cache_time_offset(double time_offset)
68 { cache_time_offset = time_offset; }
70 bool get_body(double t, SGMatrixd& bodyToWorld, SGVec3d& linearVel,
71 SGVec3d& angularVel, simgear::BVHNode::Id id);
73 // Return the nearest catapult to the given point
74 // pt in wgs84 coordinates.
75 double get_cat(double t, const SGVec3d& pt,
76 SGVec3d end[2], SGVec3d vel[2]);
79 // Return the altitude above ground below the wgs84 point pt
80 // Search for highest triangle not higher than pt + max_altoff.
81 // Return ground properties like the maximum load
82 // this kind kind of ground can carry, the friction factor between
83 // 0 and 1 which can be used to model lower friction with wet runways.
84 bool get_agl(double t, const SGVec3d& pt, SGVec3d& contact,
85 SGVec3d& normal, SGVec3d& linearVel, SGVec3d& angularVel,
86 simgear::BVHNode::Id& id, const SGMaterial*& material);
88 bool get_nearest(double t, const SGVec3d& pt, double maxDist,
89 SGVec3d& contact, SGVec3d& linearVel, SGVec3d& angularVel,
90 simgear::BVHNode::Id& id, const SGMaterial*& material);
92 // Return 1 if the hook intersects with a wire.
93 // That test is done by checking if the quad spanned by the points pt*
94 // intersects with the line representing the wire.
95 // If the wire is caught, the cache will trace this wires endpoints until
96 // the FDM calls release_wire().
97 bool caught_wire(double t, const SGVec3d pt[4]);
99 // Return the location and speed of the wire endpoints.
100 bool get_wire_ends(double t, SGVec3d end[2], SGVec3d vel[2]);
102 // Tell the cache code that it does no longer need to care for
103 // the wire end position.
104 void release_wire(void);
109 class CatapultFinder;
110 class WireIntersector;
113 // Approximate ground radius.
114 // In case the aircraft is too high above ground.
116 // the simgear material reference, contains friction coeficients ...
117 const SGMaterial* _material;
118 // The time reference for later call to intersection test routines.
119 // Is required since we will have moving triangles in carriers.
120 double cache_ref_time;
121 // The time the cache was initialized.
122 double cache_time_offset;
123 // The wire to track.
124 const simgear::BVHLineGeometry* _wire;
126 // The point and radius where the cache is built around.
127 // That are the arguments that were given to prepare_ground_cache.
128 SGVec3d reference_wgs84_point;
129 double reference_vehicle_radius;
133 SGSharedPtr<simgear::BVHNode> _localBvhTree;