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,
57 /* calculate view position in current FG view coordinate system */
58 v->view_pos = fgPolarToCart(FG_Longitude, FG_Lat_geocentric,
59 FG_Radius_to_vehicle * FEET_TO_METER + 1.0);
60 v->view_pos.x -= scenery.center.x;
61 v->view_pos.y -= scenery.center.y;
62 v->view_pos.z -= scenery.center.z;
64 printf("View pos = %.4f, %.4f, %.4f\n",
65 v->view_pos.x, v->view_pos.y, v->view_pos.z);
67 /* Derive the LOCAL aircraft rotation matrix (roll, pitch, yaw) */
68 MAT3_SET_VEC(vec, 0.0, 0.0, 1.0);
69 MAT3rotate(R, vec, FG_Phi);
70 /* printf("Roll matrix\n"); */
71 /* MAT3print(R, stdout); */
73 MAT3_SET_VEC(vec, 0.0, 1.0, 0.0);
74 /* MAT3mult_vec(vec, vec, R); */
75 MAT3rotate(TMP, vec, FG_Theta);
76 /* printf("Pitch matrix\n"); */
77 /* MAT3print(TMP, stdout); */
80 MAT3_SET_VEC(vec, 1.0, 0.0, 0.0);
81 /* MAT3mult_vec(vec, vec, R); */
82 /* MAT3rotate(TMP, vec, FG_Psi - FG_PI_2); */
83 MAT3rotate(TMP, vec, -FG_Psi);
84 /* printf("Yaw matrix\n");
85 MAT3print(TMP, stdout); */
86 MAT3mult(LOCAL, R, TMP);
87 /* printf("LOCAL matrix\n"); */
88 /* MAT3print(LOCAL, stdout); */
90 /* Derive the local UP transformation matrix based on *geodetic*
92 MAT3_SET_VEC(vec, 0.0, 0.0, 1.0);
93 MAT3rotate(R, vec, FG_Longitude); /* R = rotate about Z axis */
94 /* printf("Longitude matrix\n"); */
95 /* MAT3print(R, stdout); */
97 MAT3_SET_VEC(vec, 0.0, 1.0, 0.0);
98 MAT3mult_vec(vec, vec, R);
99 MAT3rotate(TMP, vec, -FG_Latitude); /* TMP = rotate about X axis */
100 /* printf("Latitude matrix\n"); */
101 /* MAT3print(TMP, stdout); */
103 MAT3mult(UP, R, TMP);
104 /* printf("Local up matrix\n"); */
105 /* MAT3print(UP, stdout); */
107 MAT3_SET_VEC(v->local_up, 1.0, 0.0, 0.0);
108 MAT3mult_vec(v->local_up, v->local_up, UP);
110 printf(" Local Up = (%.4f, %.4f, %.4f)\n",
111 v->local_up[0], v->local_up[1], v->local_up[2]);
113 /* Alternative method to Derive local up vector based on
114 * *geodetic* coordinates */
115 /* alt_up = fgPolarToCart(FG_Longitude, FG_Latitude, 1.0); */
116 /* printf(" Alt Up = (%.4f, %.4f, %.4f)\n",
117 alt_up.x, alt_up.y, alt_up.z); */
119 /* Derive the VIEW matrix */
120 MAT3mult(VIEW, LOCAL, UP);
121 /* printf("VIEW matrix\n"); */
122 /* MAT3print(VIEW, stdout); */
124 /* generate the current up, forward, and fwrd-view vectors */
125 MAT3_SET_VEC(vec, 1.0, 0.0, 0.0);
126 MAT3mult_vec(v->view_up, vec, VIEW);
128 MAT3_SET_VEC(vec, 0.0, 0.0, 1.0);
129 MAT3mult_vec(forward, vec, VIEW);
130 printf("Forward vector is (%.2f,%.2f,%.2f)\n", forward[0], forward[1],
133 MAT3rotate(TMP, v->view_up, v->view_offset);
134 MAT3mult_vec(v->view_forward, forward, TMP);
140 /* Revision 1.4 1997/12/17 23:13:36 curt
141 /* Began working on rendering a sky.
143 * Revision 1.3 1997/12/15 23:54:50 curt
144 * Add xgl wrappers for debugging.
145 * Generate terrain normals on the fly.
147 * Revision 1.2 1997/12/10 22:37:48 curt
148 * Prepended "fg" on the name of all global structures that didn't have it yet.
149 * i.e. "struct WEATHER {}" became "struct fgWEATHER {}"
151 * Revision 1.1 1997/08/27 21:31:17 curt