1 /**************************************************************************
2 * obj.c -- routines to handle WaveFront .obj format files.
4 * Written by Curtis Olson, started October 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 **************************************************************************/
36 #include <Main/fg_debug.h>
37 #include <Math/mat3.h>
38 #include <Scenery/obj.h>
39 #include <Scenery/scenery.h>
43 #define MAXNODES 100000
45 float nodes[MAXNODES][3];
46 float normals[MAXNODES][3];
49 /* given three points defining a triangle, calculate the normal */
50 void calc_normal(float p1[3], float p2[3], float p3[3], double normal[3])
55 v1[0] = p2[0] - p1[0]; v1[1] = p2[1] - p1[1]; v1[2] = p2[2] - p1[2];
56 v2[0] = p3[0] - p1[0]; v2[1] = p3[1] - p1[1]; v2[2] = p3[2] - p1[2];
58 MAT3cross_product(normal, v1, v2);
59 MAT3_NORMALIZE_VEC(normal,temp);
61 /* fgPrintf( FG_TERRAIN, FG_DEBUG, " Normal = %.2f %.2f %.2f\n",
62 normal[0], normal[1], normal[2]);*/
66 /* Load a .obj file and generate the GL call list */
67 GLint fgObjLoad(char *path, struct fgCartesianPoint *ref) {
68 char line[256], winding_str[256];
69 double approx_normal[3], normal[3], scale;
70 float x, y, z, xmax, xmin, ymax, ymin, zmax, zmin;
73 int first, ncount, vncount, n1, n2, n3, n4;
74 static int use_vertex_norms = 1;
76 int last1, last2, odd;
78 if ( (f = fopen(path, "r")) == NULL ) {
79 fgPrintf(FG_TERRAIN, FG_ALERT, "Cannot open file: %s\n", path);
84 tile = xglGenLists(1);
85 xglNewList(tile, GL_COMPILE);
91 while ( fgets(line, 250, f) != NULL ) {
92 if ( line[0] == '#' ) {
93 /* comment -- ignore */
94 } else if ( line[0] == '\n' ) {
95 /* empty line -- ignore */
96 } else if ( strncmp(line, "v ", 2) == 0 ) {
98 if ( ncount < MAXNODES ) {
99 /* fgPrintf( FG_TERRAIN, FG_DEBUG, "vertex = %s", line); */
100 sscanf(line, "v %f %f %f\n", &x, &y, &z);
101 nodes[ncount][0] = x;
102 nodes[ncount][1] = y;
103 nodes[ncount][2] = z;
105 /* first time through set min's and max'es */
115 /* keep track of min/max vertex values */
116 if ( x < xmin ) xmin = x;
117 if ( x > xmax ) xmax = x;
118 if ( y < ymin ) ymin = y;
119 if ( y > ymax ) ymax = y;
120 if ( z < zmin ) zmin = z;
121 if ( z > zmax ) zmax = z;
123 /* reference point is the "center" */
124 /* this is overkill to calculate it everytime we get a
125 * new node, but it's hard to know with the .obj
126 * format when we are done with vertices */
127 ref->x = (xmin + xmax) / 2;
128 ref->y = (ymin + ymax) / 2;
129 ref->z = (zmin + zmax) / 2;
133 fgPrintf( FG_TERRAIN, FG_EXIT,
134 "Read too many nodes ... dying :-(\n");
136 } else if ( strncmp(line, "vn ", 3) == 0 ) {
138 if ( vncount < MAXNODES ) {
139 /* fgPrintf( FG_TERRAIN, FG_DEBUG, "vertex normal = %s", line); */
140 sscanf(line, "vn %f %f %f\n",
141 &normals[vncount][0], &normals[vncount][1],
142 &normals[vncount][2]);
145 fgPrintf( FG_TERRAIN, FG_EXIT,
146 "Read too many vertex normals ... dying :-(\n");
148 } else if ( strncmp(line, "winding ", 8) == 0 ) {
149 sscanf(line+8, "%s", winding_str);
150 fgPrintf( FG_TERRAIN, FG_DEBUG, " WINDING = %s\n", winding_str);
152 /* can't call xglFrontFace() between xglBegin() & xglEnd() */
156 if ( strcmp(winding_str, "cw") == 0 ) {
157 xglFrontFace( GL_CW );
160 glFrontFace ( GL_CCW );
163 } else if ( line[0] == 't' ) {
164 /* start a new triangle strip */
166 n1 = n2 = n3 = n4 = 0;
169 /* close out the previous structure and start the next */
175 /* fgPrintf( FG_TERRAIN, FG_DEBUG, " new tri strip = %s",
177 sscanf(line, "t %d %d %d %d\n", &n1, &n2, &n3, &n4);
179 /* fgPrintf( FG_TERRAIN, FG_DEBUG, "(t) = "); */
181 xglBegin(GL_TRIANGLE_STRIP);
191 if ( use_vertex_norms ) {
192 MAT3_SCALE_VEC(normal, normals[n1], scale);
193 xglNormal3dv(normal);
194 xglVertex3d(nodes[n1][0] - ref->x, nodes[n1][1] - ref->y,
195 nodes[n1][2] - ref->z);
197 MAT3_SCALE_VEC(normal, normals[n2], scale);
198 xglNormal3dv(normal);
199 xglVertex3d(nodes[n2][0] - ref->x, nodes[n2][1] - ref->y,
200 nodes[n2][2] - ref->z);
202 MAT3_SCALE_VEC(normal, normals[n3], scale);
203 xglNormal3dv(normal);
204 xglVertex3d(nodes[n3][0] - ref->x, nodes[n3][1] - ref->y,
205 nodes[n3][2] - ref->z);
208 calc_normal(nodes[n1], nodes[n2], nodes[n3], approx_normal);
210 calc_normal(nodes[n2], nodes[n1], nodes[n3], approx_normal);
212 MAT3_SCALE_VEC(normal, approx_normal, scale);
213 xglNormal3dv(normal);
215 xglVertex3d(nodes[n1][0] - ref->x, nodes[n1][1] - ref->y,
216 nodes[n1][2] - ref->z);
217 xglVertex3d(nodes[n2][0] - ref->x, nodes[n2][1] - ref->y,
218 nodes[n2][2] - ref->z);
219 xglVertex3d(nodes[n3][0] - ref->x, nodes[n3][1] - ref->y,
220 nodes[n3][2] - ref->z);
228 if ( use_vertex_norms ) {
229 MAT3_SCALE_VEC(normal, normals[n4], scale);
231 calc_normal(nodes[n3], nodes[n2], nodes[n4], approx_normal);
232 MAT3_SCALE_VEC(normal, approx_normal, scale);
234 xglNormal3dv(normal);
235 xglVertex3d(nodes[n4][0] - ref->x, nodes[n4][1] - ref->y,
236 nodes[n4][2] - ref->z);
242 } else if ( line[0] == 'f' ) {
243 /* unoptimized face */
246 /* close out the previous structure and start the next */
252 xglBegin(GL_TRIANGLES);
254 /* fgPrintf( FG_TERRAIN, FG_DEBUG, "new triangle = %s", line);*/
255 sscanf(line, "f %d %d %d\n", &n1, &n2, &n3);
257 xglNormal3d(normals[n1][0], normals[n1][1], normals[n1][2]);
258 xglVertex3d(nodes[n1][0] - ref->x, nodes[n1][1] - ref->y,
259 nodes[n1][2] - ref->z);
261 xglNormal3d(normals[n2][0], normals[n2][1], normals[n2][2]);
262 xglVertex3d(nodes[n2][0] - ref->x, nodes[n2][1] - ref->y,
263 nodes[n2][2] - ref->z);
265 xglNormal3d(normals[n3][0], normals[n3][1], normals[n3][2]);
266 xglVertex3d(nodes[n3][0] - ref->x, nodes[n3][1] - ref->y,
267 nodes[n3][2] - ref->z);
268 } else if ( line[0] == 'q' ) {
269 /* continue a triangle strip */
272 /* fgPrintf( FG_TERRAIN, FG_DEBUG, "continued tri strip = %s ",
274 sscanf(line, "q %d %d\n", &n1, &n2);
275 /* fgPrintf( FG_TERRAIN, FG_DEBUG, "read %d %d\n", n1, n2); */
277 if ( use_vertex_norms ) {
278 MAT3_SCALE_VEC(normal, normals[n1], scale);
279 xglNormal3dv(normal);
282 calc_normal(nodes[last1], nodes[last2], nodes[n1],
285 calc_normal(nodes[last2], nodes[last1], nodes[n1],
288 MAT3_SCALE_VEC(normal, approx_normal, scale);
289 xglNormal3dv(normal);
292 xglVertex3d(nodes[n1][0] - ref->x, nodes[n1][1] - ref->y,
293 nodes[n1][2] - ref->z);
300 /* fgPrintf( FG_TERRAIN, FG_DEBUG, " (cont)\n"); */
302 if ( use_vertex_norms ) {
303 MAT3_SCALE_VEC(normal, normals[n2], scale);
304 xglNormal3dv(normal);
307 calc_normal(nodes[last1], nodes[last2], nodes[n2],
310 calc_normal(nodes[last2], nodes[last1], nodes[n2],
313 MAT3_SCALE_VEC(normal, approx_normal, scale);
314 xglNormal3dv(normal);
317 xglVertex3d(nodes[n2][0] - ref->x, nodes[n2][1] - ref->y,
318 nodes[n2][2] - ref->z);
325 fgPrintf( FG_TERRAIN, FG_WARN, "Unknown line in %s = %s\n",
332 /* Draw normal vectors (for visually verifying normals)*/
335 xglColor3f(0.0, 0.0, 0.0);
336 for ( i = 0; i < ncount; i++ ) {
337 xglVertex3d(nodes[i][0] - ref->x,
338 nodes[i][1] - ref->y,
339 nodes[i][2] - ref->z);
340 xglVertex3d(nodes[i][0] - ref->x + 500*normals[i][0],
341 nodes[i][1] - ref->y + 500*normals[i][1],
342 nodes[i][2] - ref->z + 500*normals[i][2]);
347 xglFrontFace ( GL_CCW );
358 /* Revision 1.20 1998/01/29 00:51:39 curt
359 /* First pass at tile cache, dynamic tile loading and tile unloading now works.
361 * Revision 1.19 1998/01/27 03:26:42 curt
362 * Playing with new fgPrintf command.
364 * Revision 1.18 1998/01/19 19:27:16 curt
365 * Merged in make system changes from Bob Kuehne <rpk@sgi.com>
366 * This should simplify things tremendously.
368 * Revision 1.17 1998/01/13 00:23:10 curt
369 * Initial changes to support loading and management of scenery tiles. Note,
370 * there's still a fair amount of work left to be done.
372 * Revision 1.16 1997/12/30 23:09:40 curt
373 * Worked on winding problem without luck, so back to calling glFrontFace()
374 * 3 times for each scenery area.
376 * Revision 1.15 1997/12/30 20:47:51 curt
377 * Integrated new event manager with subsystem initializations.
379 * Revision 1.14 1997/12/30 01:38:46 curt
380 * Switched back to per vertex normals and smooth shading for terrain.
382 * Revision 1.13 1997/12/18 23:32:36 curt
383 * First stab at sky dome actually starting to look reasonable. :-)
385 * Revision 1.12 1997/12/17 23:13:47 curt
386 * Began working on rendering the sky.
388 * Revision 1.11 1997/12/15 23:55:01 curt
389 * Add xgl wrappers for debugging.
390 * Generate terrain normals on the fly.
392 * Revision 1.10 1997/12/12 21:41:28 curt
393 * More light/material property tweaking ... still a ways off.
395 * Revision 1.9 1997/12/12 19:52:57 curt
396 * Working on lightling and material properties.
398 * Revision 1.8 1997/12/10 01:19:51 curt
399 * Tweaks for verion 0.15 release.
401 * Revision 1.7 1997/12/08 22:51:17 curt
402 * Enhanced to handle ccw and cw tri-stripe winding. This is a temporary
403 * admission of defeat. I will eventually go back and get all the stripes
404 * wound the same way (ccw).
406 * Revision 1.6 1997/11/25 19:25:35 curt
407 * Changes to integrate Durk's moon/sun code updates + clean up.
409 * Revision 1.5 1997/11/15 18:16:39 curt
412 * Revision 1.4 1997/11/14 00:26:49 curt
413 * Transform scenery coordinates earlier in pipeline when scenery is being
414 * created, not when it is being loaded. Precalculate normals for each node
415 * as average of the normals of each containing polygon so Garoude shading is
418 * Revision 1.3 1997/10/31 04:49:12 curt
419 * Tweaking vertex orders.
421 * Revision 1.2 1997/10/30 12:38:45 curt
422 * Working on new scenery subsystem.
424 * Revision 1.1 1997/10/28 21:14:54 curt