1 /**************************************************************************
2 * mesh.c -- data structures and routines for processing terrain meshes
4 * Written by Curtis Olson, started May 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 **************************************************************************/
32 # include <Windows32/Base.h>
36 #include <stdlib.h> /* atof(), atoi() */
46 /* Temporary hack until we get the scenery management system running */
47 extern GLint mesh_hack;
48 extern struct mesh eg;
50 /* initialize the non-array mesh values */
51 void mesh_init(struct mesh *m) {
67 /* return a pointer to a new mesh structure (no data array allocated yet) */
68 struct mesh *(new_mesh)() {
69 struct mesh *mesh_ptr;
71 mesh_ptr = (struct mesh *)malloc(sizeof(struct mesh));
73 if ( mesh_ptr == 0 ) {
74 printf("Virtual memory exceeded\n");
78 mesh_ptr->cur_row = 0;
79 mesh_ptr->cur_col = 0;
85 /* return a pointer to a dynamically allocated array */
86 float *(new_mesh_data)(int nrows, int ncols) {
89 mesh_data_ptr = (float *)malloc(nrows * ncols * sizeof(float));
91 if ( mesh_data_ptr == 0 ) {
92 printf("Virtual memory exceeded\n");
96 printf("Allocated float(%d, %d)\n", nrows, ncols);
98 return(mesh_data_ptr);
102 /* set the option name in the mesh data structure */
103 void mesh_set_option_name(struct mesh *m, char *name) {
104 if ( strlen(name) < MAX_IDENT_LEN ) {
105 strcpy(m->option_name, name);
107 strncpy(m->option_name, name, MAX_IDENT_LEN - 1);
108 m->option_name[MAX_IDENT_LEN - 1] = '\0';
110 if ( strcmp(m->option_name, "do_data") == 0 ) {
118 /* set an option value in the mesh data structure */
119 void mesh_set_option_value(struct mesh *m, char *value) {
120 /* printf("Setting %s to %s\n", m->option_name, value); */
123 /* mesh data is a pseudo 2d array */
124 /* printf("Setting mesh_data[%d][%d] to %s\n", m->cur_row, m->cur_col,
126 m->mesh_data[m->cur_row * m->cols + m->cur_col] = atof(value);
128 if ( m->cur_col >= m->cols ) {
131 if ( m->cur_row > m->rows ) {
135 } else if ( strcmp(m->option_name, "origin_lon") == 0 ) {
136 m->originx = atof(value);
137 } else if ( strcmp(m->option_name, "origin_lat") == 0 ) {
138 m->originy = atof(value);
139 } else if ( strcmp(m->option_name, "rows") == 0 ) {
140 m->rows = atoi(value);
141 } else if ( strcmp(m->option_name, "cols") == 0 ) {
142 m->cols = atoi(value);
143 } else if ( strcmp(m->option_name, "row_step") == 0 ) {
144 m->row_step = atof(value);
145 } else if ( strcmp(m->option_name, "col_step") == 0 ) {
146 m->col_step = atof(value);
148 printf("Unknown option %s with value %s, ignoring ...\n",
149 m->option_name, value);
154 /* do whatever needs to be done with the mesh now that it's been
155 loaded, such as generating the OpenGL call list. */
156 void mesh_do_it(struct mesh *m) {
157 mesh_hack = mesh2GL(m);
161 /* return the current altitude based on mesh data. We should rewrite
162 * this to interpolate exact values, but for now this is good enough */
163 double mesh_altitude(double lon, double lat) {
164 /* we expect incoming (lon,lat) to be in arcsec for now */
166 double xlocal, ylocal, dx, dy, zA, zB, elev;
167 int x1, y1, z1, x2, y2, z2, x3, y3, z3;
171 skip = cur_scenery_params.terrain_skip;
172 /* determine if we are in the lower triangle or the upper triangle
180 then calculate our end points
183 xlocal = (lon - eg.originx) / eg.col_step;
184 ylocal = (lat - eg.originy) / eg.row_step;
186 xindex = (int)(xlocal / skip) * skip;
187 yindex = (int)(ylocal / skip) * skip;
189 if ( (xindex < 0) || (xindex + skip >= eg.cols) ||
190 (yindex < 0) || (yindex + skip >= eg.rows) ) {
194 dx = xlocal - xindex;
195 dy = ylocal - yindex;
199 /* printf(" Lower triangle\n"); */
203 z1 = eg.mesh_data[y1 * eg.cols + x1];
207 z2 = eg.mesh_data[y2 * eg.cols + x2];
211 z3 = eg.mesh_data[y3 * eg.cols + x3];
213 /* printf(" dx = %.2f dy = %.2f\n", dx, dy);
214 printf(" (x1,y1,z1) = (%d,%d,%d)\n", x1, y1, z1);
215 printf(" (x2,y2,z2) = (%d,%d,%d)\n", x2, y2, z2);
216 printf(" (x3,y3,z3) = (%d,%d,%d)\n", x3, y3, z3); */
218 zA = dx * (z2 - z1) / skip + z1;
219 zB = dx * (z3 - z1) / skip + z1;
221 /* printf(" zA = %.2f zB = %.2f\n", zA, zB); */
223 elev = dy * (zB - zA) / dx + zA;
226 /* printf(" Upper triangle\n"); */
230 z1 = eg.mesh_data[y1 * eg.cols + x1];
234 z2 = eg.mesh_data[y2 * eg.cols + x2];
238 z3 = eg.mesh_data[y3 * eg.cols + x3];
240 /* printf(" dx = %.2f dy = %.2f\n", dx, dy);
241 printf(" (x1,y1,z1) = (%d,%d,%d)\n", x1, y1, z1);
242 printf(" (x2,y2,z2) = (%d,%d,%d)\n", x2, y2, z2);
243 printf(" (x3,y3,z3) = (%d,%d,%d)\n", x3, y3, z3); */
245 zA = dy * (z2 - z1) / skip + z1;
246 zB = dy * (z3 - z1) / skip + z1;
248 /* printf(" zA = %.2f zB = %.2f\n", zA, zB );
249 printf(" xB - xA = %.2f\n", eg.col_step * dy / eg.row_step); */
251 elev = dx * (zB - zA) / dy + zA;
259 /* Revision 1.14 1997/07/12 04:01:14 curt
260 /* Added #include <Windows32/Base.h> to help Win32 compiling.
262 * Revision 1.13 1997/07/12 02:27:11 curt
263 * Looking at potential scenery transformation/coordinate system problems.
265 * Revision 1.12 1997/07/11 03:23:19 curt
266 * Solved some scenery display/orientation problems. Still have a positioning
267 * (or transformation?) problem.
269 * Revision 1.11 1997/07/11 01:30:02 curt
270 * More tweaking of terrian floor.
272 * Revision 1.10 1997/07/10 04:26:38 curt
273 * We now can interpolated ground elevation for any position in the grid. We
274 * can use this to enforce a "hard" ground. We still need to enforce some
275 * bounds checking so that we don't try to lookup data points outside the
278 * Revision 1.9 1997/07/10 02:22:10 curt
279 * Working on terrain elevation interpolation routine.
281 * Revision 1.8 1997/07/09 21:31:15 curt
282 * Working on making the ground "hard."
284 * Revision 1.7 1997/07/08 18:20:13 curt
285 * Working on establishing a hard ground.
287 * Revision 1.6 1997/06/29 21:16:49 curt
288 * More twiddling with the Scenery Management system.
290 * Revision 1.5 1997/06/22 21:44:41 curt
291 * Working on intergrating the VRML (subset) parser.
293 * Revision 1.4 1997/05/30 19:30:17 curt
294 * The LaRCsim flight model is starting to look like it is working.
296 * Revision 1.3 1997/05/23 15:40:41 curt
297 * Added GNU copyright headers.
299 * Revision 1.2 1997/05/19 18:20:50 curt
300 * Slight change to origin key words.
302 * Revision 1.1 1997/05/16 16:07:04 curt