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 **************************************************************************/
38 #include "../Math/mat3.h"
42 #define MAXNODES 100000
44 float nodes[MAXNODES][3];
45 float normals[MAXNODES][3];
48 /* Load a .obj file and generate the GL call list */
49 GLint fgObjLoad(char *path) {
50 char line[256], winding[256];
51 double v1[3], v2[3], approx_normal[3], dot_prod, temp;
52 struct fgCartesianPoint ref;
55 int first, ncount, vncount, n1, n2, n3, n4;
58 if ( (f = fopen(path, "r")) == NULL ) {
59 printf("Cannot open file: %s\n", path);
64 glNewList(area, GL_COMPILE);
70 while ( fgets(line, 250, f) != NULL ) {
71 if ( line[0] == '#' ) {
72 /* comment -- ignore */
73 } else if ( strncmp(line, "v ", 2) == 0 ) {
75 if ( ncount < MAXNODES ) {
76 /* printf("vertex = %s", line); */
77 sscanf(line, "v %f %f %f\n",
78 &nodes[ncount][0], &nodes[ncount][1], &nodes[ncount][2]);
80 /* first node becomes the reference point */
81 ref.x = nodes[ncount][0];
82 ref.y = nodes[ncount][1];
83 ref.z = nodes[ncount][2];
88 printf("Read too many nodes ... dying :-(\n");
91 } else if ( strncmp(line, "vn ", 3) == 0 ) {
93 if ( vncount < MAXNODES ) {
94 /* printf("vertex normal = %s", line); */
95 sscanf(line, "vn %f %f %f\n",
96 &normals[vncount][0], &normals[vncount][1],
97 &normals[vncount][2]);
100 printf("Read too many vertex normals ... dying :-(\n");
103 } else if ( strncmp(line, "winding ", 8) == 0 ) {
104 sscanf(line+8, "%s", winding);
105 printf("WINDING = %s\n", winding);
107 /* can't call glFrontFace() between glBegin() & glEnd() */
111 if ( strcmp(winding, "cw") == 0 ) {
112 glFrontFace( GL_CW );
114 glFrontFace ( GL_CCW );
116 } else if ( line[0] == 't' ) {
117 /* start a new triangle strip */
119 n1 = n2 = n3 = n4 = 0;
122 /* close out the previous structure and start the next */
128 /* printf("new tri strip = %s", line); */
129 sscanf(line, "t %d %d %d %d\n", &n1, &n2, &n3, &n4);
131 /* printf("(t) = "); */
133 /* try to get the proper rotation by calculating an
134 * approximate normal and seeing if it is close to the
135 * precalculated normal */
136 /*v1[0] = nodes[n2][0] - nodes[n1][0];
137 v1[1] = nodes[n2][1] - nodes[n1][1];
138 v1[2] = nodes[n2][2] - nodes[n1][2];
139 v2[0] = nodes[n3][0] - nodes[n1][0];
140 v2[1] = nodes[n3][1] - nodes[n1][1];
141 v2[2] = nodes[n3][2] - nodes[n1][2];
142 MAT3cross_product(approx_normal, v1, v2);
143 MAT3_NORMALIZE_VEC(approx_normal,temp);
144 printf("Approx normal = %.2f %.2f %.2f\n", approx_normal[0],
145 approx_normal[1], approx_normal[2]);
146 dot_prod = MAT3_DOT_PRODUCT(normals[n1], approx_normal);
147 printf("Dot product = %.4f\n", dot_prod); */
148 /* angle = acos(dot_prod); */
149 /* printf("Normal ANGLE = %.3f rads.\n", angle); */
151 /* if ( dot_prod < -0.5 ) {
152 glFrontFace( GL_CW );
154 glFrontFace( GL_CCW );
157 glBegin(GL_TRIANGLE_STRIP);
159 glNormal3d(normals[n1][0], normals[n1][1], normals[n1][2]);
160 glVertex3d(nodes[n1][0] - ref.x, nodes[n1][1] - ref.y,
161 nodes[n1][2] - ref.z);
163 glNormal3d(normals[n2][0], normals[n2][1], normals[n2][2]);
164 glVertex3d(nodes[n2][0] - ref.x, nodes[n2][1] - ref.y,
165 nodes[n2][2] - ref.z);
167 glNormal3d(normals[n3][0], normals[n3][1], normals[n3][2]);
168 glVertex3d(nodes[n3][0] - ref.x, nodes[n3][1] - ref.y,
169 nodes[n3][2] - ref.z);
172 glNormal3d(normals[n4][0], normals[n4][1], normals[n4][2]);
173 glVertex3d(nodes[n4][0] - ref.x, nodes[n4][1] - ref.y,
174 nodes[n4][2] - ref.z);
176 } else if ( line[0] == 'f' ) {
177 /* unoptimized face */
180 /* close out the previous structure and start the next */
186 glBegin(GL_TRIANGLES);
188 /* printf("new triangle = %s", line);*/
189 sscanf(line, "f %d %d %d\n", &n1, &n2, &n3);
191 glNormal3d(normals[n1][0], normals[n1][1], normals[n1][2]);
192 glVertex3d(nodes[n1][0] - ref.x, nodes[n1][1] - ref.y,
193 nodes[n1][2] - ref.z);
195 glNormal3d(normals[n2][0], normals[n2][1], normals[n2][2]);
196 glVertex3d(nodes[n2][0] - ref.x, nodes[n2][1] - ref.y,
197 nodes[n2][2] - ref.z);
199 glNormal3d(normals[n3][0], normals[n3][1], normals[n3][2]);
200 glVertex3d(nodes[n3][0] - ref.x, nodes[n3][1] - ref.y,
201 nodes[n3][2] - ref.z);
202 } else if ( line[0] == 'q' ) {
203 /* continue a triangle strip */
206 /* printf("continued tri strip = %s ", line); */
207 sscanf(line, "q %d %d\n", &n1, &n2);
208 /* printf("read %d %d\n", n1, n2); */
210 glNormal3d(normals[n1][0], normals[n1][1], normals[n1][2]);
211 glVertex3d(nodes[n1][0] - ref.x, nodes[n1][1] - ref.y,
212 nodes[n1][2] - ref.z);
215 /* printf(" (cont)\n"); */
216 glNormal3d(normals[n2][0], normals[n2][1], normals[n2][2]);
217 glVertex3d(nodes[n2][0] - ref.x, nodes[n2][1] - ref.y,
218 nodes[n2][2] - ref.z);
221 printf("Unknown line in %s = %s\n", path, line);
227 /* Draw normal vectors (for visually verifying normals)*/
230 glColor3f(0.0, 0.0, 0.0);
231 for ( i = 0; i < ncount; i++ ) {
232 glVertex3d(nodes[i][0] - ref.x,
234 nodes[i][2] - ref.z);
235 glVertex3d(nodes[i][0] - ref.x + 500*normals[i][0],
236 nodes[i][1] - ref.y + 500*normals[i][1],
237 nodes[i][2] - ref.z + 500*normals[i][2]);
251 /* Revision 1.10 1997/12/12 21:41:28 curt
252 /* More light/material property tweaking ... still a ways off.
254 * Revision 1.9 1997/12/12 19:52:57 curt
255 * Working on lightling and material properties.
257 * Revision 1.8 1997/12/10 01:19:51 curt
258 * Tweaks for verion 0.15 release.
260 * Revision 1.7 1997/12/08 22:51:17 curt
261 * Enhanced to handle ccw and cw tri-stripe winding. This is a temporary
262 * admission of defeat. I will eventually go back and get all the stripes
263 * wound the same way (ccw).
265 * Revision 1.6 1997/11/25 19:25:35 curt
266 * Changes to integrate Durk's moon/sun code updates + clean up.
268 * Revision 1.5 1997/11/15 18:16:39 curt
271 * Revision 1.4 1997/11/14 00:26:49 curt
272 * Transform scenery coordinates earlier in pipeline when scenery is being
273 * created, not when it is being loaded. Precalculate normals for each node
274 * as average of the normals of each containing polygon so Garoude shading is
277 * Revision 1.3 1997/10/31 04:49:12 curt
278 * Tweaking vertex orders.
280 * Revision 1.2 1997/10/30 12:38:45 curt
281 * Working on new scenery subsystem.
283 * Revision 1.1 1997/10/28 21:14:54 curt