1 // viewer_lookat.hxx -- class for managing a "look at" viewer in
2 // the flightgear world.
4 // Written by Curtis Olson, started October 2000.
6 // Copyright (C) 2000 Curtis L. Olson - curt@flightgear.org
8 // This program is free software; you can redistribute it and/or
9 // modify it under the terms of the GNU General Public License as
10 // published by the Free Software Foundation; either version 2 of the
11 // License, or (at your option) any later version.
13 // This program is distributed in the hope that it will be useful, but
14 // WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 // General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25 #include <simgear/compiler.h>
31 #include <plib/ssg.h> // plib include
33 #include <simgear/constants.h>
34 #include <simgear/debug/logstream.hxx>
35 #include <simgear/math/point3d.hxx>
36 #include <simgear/math/polar3d.hxx>
37 #include <simgear/math/vector.hxx>
39 #include <Scenery/scenery.hxx>
41 #include "globals.hxx"
42 #include "viewer_lookat.hxx"
46 FGViewerLookAt::FGViewerLookAt( void )
51 void fgMakeLookAtMat4 ( sgMat4 dst, const sgVec3 eye, const sgVec3 center,
55 // 1) In order to compute the line of sight, the eye point must not be equal
56 // to the center point.
57 // 2) The up vector must not be parallel to the line of sight from the eye
58 // to the center point.
60 /* Compute the direction vectors */
63 /* Y vector = center - eye */
64 sgSubVec3 ( y, center, eye ) ;
67 sgCopyVec3 ( z, up ) ;
69 /* X vector = Y cross Z */
70 sgVectorProductVec3 ( x, y, z ) ;
72 /* Recompute Z = X cross Y */
73 sgVectorProductVec3 ( z, x, y ) ;
75 /* Normalize everything */
76 sgNormaliseVec3 ( x ) ;
77 sgNormaliseVec3 ( y ) ;
78 sgNormaliseVec3 ( z ) ;
80 /* Build the matrix */
81 #define M(row,col) dst[row][col]
82 M(0,0) = x[0]; M(0,1) = x[1]; M(0,2) = x[2]; M(0,3) = 0.0;
83 M(1,0) = y[0]; M(1,1) = y[1]; M(1,2) = y[2]; M(1,3) = 0.0;
84 M(2,0) = z[0]; M(2,1) = z[1]; M(2,2) = z[2]; M(2,3) = 0.0;
85 M(3,0) = eye[0]; M(3,1) = eye[1]; M(3,2) = eye[2]; M(3,3) = 1.0;
90 // convert sgMat4 to MAT3 and print
91 static void print_sgMat4( sgMat4 &in) {
93 for ( i = 0; i < 4; i++ ) {
94 for ( j = 0; j < 4; j++ ) {
95 printf("%10.4f ", in[i][j]);
102 // Update the view parameters
103 void FGViewerLookAt::update() {
107 // calculate the cartesion coords of the current lat/lon/0 elev
108 Point3D p = Point3D( geod_view_pos[0],
112 tmp = sgPolarToCart3d(p) - scenery.center;
113 sgSetVec3( zero_elev, tmp[0], tmp[1], tmp[2] );
115 // calculate view position in current FG view coordinate system
116 // p.lon & p.lat are already defined earlier, p.radius was set to
117 // the sea level radius, so now we add in our altitude.
118 if ( geod_view_pos[2] > (scenery.cur_elev + 0.5 * METER_TO_FEET) ) {
119 p.setz( p.radius() + geod_view_pos[2] );
121 p.setz( p.radius() + scenery.cur_elev + 0.5 * METER_TO_FEET );
124 tmp = sgPolarToCart3d(p);
125 sgdSetVec3( abs_view_pos, tmp[0], tmp[1], tmp[2] );
127 // view_pos = abs_view_pos - scenery.center;
129 sgdSetVec3( sc, scenery.center.x(), scenery.center.y(), scenery.center.z());
131 sgdSubVec3( vp, abs_view_pos, sc );
132 sgSetVec3( view_pos, vp );
133 sgAddVec3( view_pos, pilot_offset );
135 FG_LOG( FG_VIEW, FG_DEBUG, "sea level radius = " << sea_level_radius );
136 FG_LOG( FG_VIEW, FG_DEBUG, "Polar view pos = " << p );
137 FG_LOG( FG_VIEW, FG_DEBUG, "Absolute view pos = "
138 << abs_view_pos[0] << ","
139 << abs_view_pos[1] << ","
140 << abs_view_pos[2] );
141 FG_LOG( FG_VIEW, FG_DEBUG, "Relative view pos = "
142 << view_pos[0] << "," << view_pos[1] << "," << view_pos[2] );
143 FG_LOG( FG_VIEW, FG_DEBUG, "pilot offset = "
144 << pilot_offset[0] << "," << pilot_offset[1] << ","
145 << pilot_offset[2] );
146 FG_LOG( FG_VIEW, FG_DEBUG, "view forward = "
147 << view_forward[0] << "," << view_forward[1] << ","
148 << view_forward[2] );
149 FG_LOG( FG_VIEW, FG_DEBUG, "view up = "
150 << view_up[0] << "," << view_up[1] << ","
153 // Make the VIEW matrix.
154 fgMakeLookAtMat4( VIEW, view_pos, view_forward, view_up );
155 // cout << "VIEW matrix" << endl;
156 // print_sgMat4( VIEW );
158 // the VIEW matrix includes both rotation and translation. Let's
159 // knock out the translation part to make the VIEW_ROT matrix
160 sgCopyMat4( VIEW_ROT, VIEW );
161 VIEW_ROT[3][0] = VIEW_ROT[3][1] = VIEW_ROT[3][2] = 0.0;
163 // Make the world up rotation matrix
165 geod_view_pos[0] * RAD_TO_DEG,
167 -geod_view_pos[1] * RAD_TO_DEG );
169 // use a clever observation into the nature of our tranformation
170 // matrix to grab the world_up vector
171 sgSetVec3( world_up, UP[0][0], UP[0][1], UP[0][2] );
172 // cout << "World Up = " << world_up[0] << "," << world_up[1] << ","
173 // << world_up[2] << endl;
176 //!!!!!!!!!!!!!!!!!!!
177 // THIS IS THE EXPERIMENTAL VIEWING ANGLE SHIFTER
178 // THE MAJORITY OF THE WORK IS DONE IN GUI.CXX
179 // this in gui.cxx for now just testing
180 extern float GuiQuat_mat[4][4];
181 sgPreMultMat4( VIEW, GuiQuat_mat);
182 // !!!!!!!!!! testing
184 // Given a vector pointing straight down (-Z), map into onto the
185 // local plane representing "horizontal". This should give us the
186 // local direction for moving "south".
187 sgSetVec3( minus_z, 0.0, 0.0, -1.0 );
189 sgmap_vec_onto_cur_surface_plane(world_up, view_pos, minus_z,
191 sgNormalizeVec3(surface_south);
192 // cout << "Surface direction directly south " << surface_south[0] << ","
193 // << surface_south[1] << "," << surface_south[2] << endl;
195 // now calculate the surface east vector
196 #define USE_FAST_SURFACE_EAST
197 #ifdef USE_FAST_SURFACE_EAST
199 sgNegateVec3(world_down, world_up);
200 sgVectorProductVec3(surface_east, surface_south, world_down);
202 sgMakeRotMat4( TMP, FG_PI_2 * RAD_TO_DEG, world_up );
203 // cout << "sgMat4 TMP" << endl;
204 // print_sgMat4( TMP );
205 sgXformVec3(surface_east, surface_south, TMP);
206 #endif // USE_FAST_SURFACE_EAST
207 // cout << "Surface direction directly east " << surface_east[0] << ","
208 // << surface_east[1] << "," << surface_east[2] << endl;
209 // cout << "Should be close to zero = "
210 // << sgScalarProductVec3(surface_south, surface_east) << endl;
217 FGViewerLookAt::~FGViewerLookAt( void ) {