1 /**************************************************************************
2 * views.c -- data structures and routines for managing and view parameters.
4 * Written by Curtis Olson, started August 1997.
6 * Copyright (C) 1997 Curtis L. Olson - curt@infoplane.com
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.
23 * (Log is kept at end of this file)
24 **************************************************************************/
29 #include "../Include/constants.h"
31 #include "../Flight/flight.h"
32 #include "../Math/mat3.h"
33 #include "../Math/polar.h"
34 #include "../Scenery/scenery.h"
37 /* This is a record containing current view parameters */
38 struct fgVIEW current_view;
41 /* Initialize a view structure */
42 void fgViewInit(struct fgVIEW *v) {
44 v->goal_view_offset = 0.0;
48 /* Update the view parameters */
49 void fgViewUpdate(struct fgFLIGHT *f, struct fgVIEW *v) {
51 MAT3mat R, TMP, UP, LOCAL, VIEW;
53 /* calculate the cartesion coords of the current lat/lon/0 elev */
54 v->cur_zero_elev = fgPolarToCart(FG_Longitude, FG_Lat_geocentric,
55 FG_Sea_level_radius * FEET_TO_METER);
56 v->cur_zero_elev.x -= scenery.center.x;
57 v->cur_zero_elev.y -= scenery.center.y;
58 v->cur_zero_elev.z -= scenery.center.z;
60 /* calculate view position in current FG view coordinate system */
61 v->view_pos = fgPolarToCart(FG_Longitude, FG_Lat_geocentric,
62 FG_Radius_to_vehicle * FEET_TO_METER + 1.0);
63 v->view_pos.x -= scenery.center.x;
64 v->view_pos.y -= scenery.center.y;
65 v->view_pos.z -= scenery.center.z;
67 printf("View pos = %.4f, %.4f, %.4f\n",
68 v->view_pos.x, v->view_pos.y, v->view_pos.z);
70 /* Derive the LOCAL aircraft rotation matrix (roll, pitch, yaw) */
71 MAT3_SET_VEC(vec, 0.0, 0.0, 1.0);
72 MAT3rotate(R, vec, FG_Phi);
73 /* printf("Roll matrix\n"); */
74 /* MAT3print(R, stdout); */
76 MAT3_SET_VEC(vec, 0.0, 1.0, 0.0);
77 /* MAT3mult_vec(vec, vec, R); */
78 MAT3rotate(TMP, vec, FG_Theta);
79 /* printf("Pitch matrix\n"); */
80 /* MAT3print(TMP, stdout); */
83 MAT3_SET_VEC(vec, 1.0, 0.0, 0.0);
84 /* MAT3mult_vec(vec, vec, R); */
85 /* MAT3rotate(TMP, vec, FG_Psi - FG_PI_2); */
86 MAT3rotate(TMP, vec, -FG_Psi);
87 /* printf("Yaw matrix\n");
88 MAT3print(TMP, stdout); */
89 MAT3mult(LOCAL, R, TMP);
90 /* printf("LOCAL matrix\n"); */
91 /* MAT3print(LOCAL, stdout); */
93 /* Derive the local UP transformation matrix based on *geodetic*
95 MAT3_SET_VEC(vec, 0.0, 0.0, 1.0);
96 MAT3rotate(R, vec, FG_Longitude); /* R = rotate about Z axis */
97 /* printf("Longitude matrix\n"); */
98 /* MAT3print(R, stdout); */
100 MAT3_SET_VEC(vec, 0.0, 1.0, 0.0);
101 MAT3mult_vec(vec, vec, R);
102 MAT3rotate(TMP, vec, -FG_Latitude); /* TMP = rotate about X axis */
103 /* printf("Latitude matrix\n"); */
104 /* MAT3print(TMP, stdout); */
106 MAT3mult(UP, R, TMP);
107 /* printf("Local up matrix\n"); */
108 /* MAT3print(UP, stdout); */
110 MAT3_SET_VEC(v->local_up, 1.0, 0.0, 0.0);
111 MAT3mult_vec(v->local_up, v->local_up, UP);
113 printf(" Local Up = (%.4f, %.4f, %.4f)\n",
114 v->local_up[0], v->local_up[1], v->local_up[2]);
116 /* Alternative method to Derive local up vector based on
117 * *geodetic* coordinates */
118 /* alt_up = fgPolarToCart(FG_Longitude, FG_Latitude, 1.0); */
119 /* printf(" Alt Up = (%.4f, %.4f, %.4f)\n",
120 alt_up.x, alt_up.y, alt_up.z); */
122 /* Derive the VIEW matrix */
123 MAT3mult(VIEW, LOCAL, UP);
124 /* printf("VIEW matrix\n"); */
125 /* MAT3print(VIEW, stdout); */
127 /* generate the current up, forward, and fwrd-view vectors */
128 MAT3_SET_VEC(vec, 1.0, 0.0, 0.0);
129 MAT3mult_vec(v->view_up, vec, VIEW);
131 MAT3_SET_VEC(vec, 0.0, 0.0, 1.0);
132 MAT3mult_vec(forward, vec, VIEW);
133 printf("Forward vector is (%.2f,%.2f,%.2f)\n", forward[0], forward[1],
136 MAT3rotate(TMP, v->view_up, v->view_offset);
137 MAT3mult_vec(v->view_forward, forward, TMP);
143 /* Revision 1.5 1997/12/18 04:07:02 curt
144 /* Worked on properly translating and positioning the sky dome.
146 * Revision 1.4 1997/12/17 23:13:36 curt
147 * Began working on rendering a sky.
149 * Revision 1.3 1997/12/15 23:54:50 curt
150 * Add xgl wrappers for debugging.
151 * Generate terrain normals on the fly.
153 * Revision 1.2 1997/12/10 22:37:48 curt
154 * Prepended "fg" on the name of all global structures that didn't have it yet.
155 * i.e. "struct WEATHER {}" became "struct fgWEATHER {}"
157 * Revision 1.1 1997/08/27 21:31:17 curt