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
30 class PolytopeIntersector;
33 #include <simgear/compiler.h>
34 #include <simgear/constants.h>
35 #include <simgear/math/SGMath.hxx>
36 #include <simgear/math/SGGeometry.hxx>
39 class WireIntersector;
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 ref_time, const SGVec3d& pt,
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 // Return the nearest catapult to the given point
62 // pt in wgs84 coordinates.
63 double get_cat(double t, const SGVec3d& pt,
64 SGVec3d end[2], SGVec3d vel[2]);
67 // Return the altitude above ground below the wgs84 point pt
68 // Search for highest triangle not higher than pt + max_altoff.
69 // Return ground properties like the ground type, the maximum load
70 // this kind kind of ground can carry, the friction factor between
71 // 0 and 1 which can be used to model lower friction with wet runways
72 // and finally the altitude above ground.
73 bool get_agl(double t, const SGVec3d& pt, double max_altoff,
74 SGVec3d& contact, SGVec3d& normal, SGVec3d& vel,
75 int *type, const SGMaterial** material, double *agl);
77 // Return 1 if the hook intersects with a wire.
78 // That test is done by checking if the quad spanned by the points pt*
79 // intersects with the line representing the wire.
80 // If the wire is caught, the cache will trace this wires endpoints until
81 // the FDM calls release_wire().
82 bool caught_wire(double t, const SGVec3d pt[4]);
84 // Return the location and speed of the wire endpoints.
85 bool get_wire_ends(double t, SGVec3d end[2], SGVec3d vel[2]);
87 // Tell the cache code that it does no longer need to care for
88 // the wire end position.
89 void release_wire(void);
92 friend class GroundCacheFillVisitor;
95 // Helper class to hold some properties of the ground triangle.
96 struct GroundProperty {
97 GroundProperty() : type(0), wire_id(0), material(0) {}
100 // The linear and angular velocity.
104 // the simgear material reference, contains friction coeficients ...
105 const SGMaterial* material;
110 // The triangle we represent
111 SGTriangled triangle;
125 // Approximate ground radius.
126 // In case the aircraft is too high above ground.
127 double ground_radius;
130 // the simgear material reference, contains friction coeficients ...
131 const SGMaterial* _material;
132 // The time reference for later call to intersection test routines.
133 // Is required since we will have moving triangles in carriers.
134 double cache_ref_time;
135 // The wire identifier to track.
138 // Containers which hold all the essential information about this cache.
139 std::vector<Triangle> triangles;
140 std::vector<Catapult> catapults;
141 std::vector<Wire> wires;
143 // The point and radius where the cache is built around.
144 // That are the arguments that were given to prepare_ground_cache.
145 SGVec3d reference_wgs84_point;
146 double reference_vehicle_radius;
150 void getGroundProperty(osg::Drawable* drawable,
151 const osg::NodePath& nodePath,
152 GroundProperty& gp, bool& backfaceCulling);
153 static void velocityTransformTriangle(double dt, SGTriangled& dst,
154 SGSphered& sdst, const Triangle& src);
155 void getTriIntersectorResults(osgUtil::PolytopeIntersector* triInt);
156 void getWireIntersectorResults(WireIntersector* wireInt,
157 double wireCacheRadius);