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 static GLfloat terrain_color[4] = { 0.6, 0.6, 0.25, 1.0 };
52 static GLfloat terrain_ambient[4];
53 static GLfloat terrain_diffuse[4];
54 double v1[3], v2[3], approx_normal[3], dot_prod, temp;
55 struct fgCartesianPoint ref;
58 int first, ncount, vncount, n1, n2, n3, n4;
61 if ( (f = fopen(path, "r")) == NULL ) {
62 printf("Cannot open file: %s\n", path);
67 glNewList(area, GL_COMPILE);
69 for ( i = 0; i < 4; i++ ) {
70 terrain_ambient[i] = terrain_color[i];
71 terrain_diffuse[i] = terrain_color[i];
74 glMaterialfv(GL_FRONT, GL_AMBIENT, terrain_ambient);
75 glMaterialfv(GL_FRONT, GL_DIFFUSE, terrain_diffuse);
81 while ( fgets(line, 250, f) != NULL ) {
82 if ( line[0] == '#' ) {
83 /* comment -- ignore */
84 } else if ( strncmp(line, "v ", 2) == 0 ) {
86 if ( ncount < MAXNODES ) {
87 /* printf("vertex = %s", line); */
88 sscanf(line, "v %f %f %f\n",
89 &nodes[ncount][0], &nodes[ncount][1], &nodes[ncount][2]);
91 /* first node becomes the reference point */
92 ref.x = nodes[ncount][0];
93 ref.y = nodes[ncount][1];
94 ref.z = nodes[ncount][2];
99 printf("Read too many nodes ... dying :-(\n");
102 } else if ( strncmp(line, "vn ", 3) == 0 ) {
104 if ( vncount < MAXNODES ) {
105 /* printf("vertex normal = %s", line); */
106 sscanf(line, "vn %f %f %f\n",
107 &normals[vncount][0], &normals[vncount][1],
108 &normals[vncount][2]);
111 printf("Read too many vertex normals ... dying :-(\n");
114 } else if ( strncmp(line, "winding ", 8) == 0 ) {
115 sscanf(line+8, "%s", winding);
116 printf("WINDING = %s\n", winding);
118 /* can't call glFrontFace() between glBegin() & glEnd() */
122 if ( strcmp(winding, "cw") == 0 ) {
123 glFrontFace( GL_CW );
125 glFrontFace ( GL_CCW );
127 } else if ( line[0] == 't' ) {
128 /* start a new triangle strip */
130 n1 = n2 = n3 = n4 = 0;
133 /* close out the previous structure and start the next */
139 /* printf("new tri strip = %s", line); */
140 sscanf(line, "t %d %d %d %d\n", &n1, &n2, &n3, &n4);
142 /* printf("(t) = "); */
144 /* try to get the proper rotation by calculating an
145 * approximate normal and seeing if it is close to the
146 * precalculated normal */
147 /*v1[0] = nodes[n2][0] - nodes[n1][0];
148 v1[1] = nodes[n2][1] - nodes[n1][1];
149 v1[2] = nodes[n2][2] - nodes[n1][2];
150 v2[0] = nodes[n3][0] - nodes[n1][0];
151 v2[1] = nodes[n3][1] - nodes[n1][1];
152 v2[2] = nodes[n3][2] - nodes[n1][2];
153 MAT3cross_product(approx_normal, v1, v2);
154 MAT3_NORMALIZE_VEC(approx_normal,temp);
155 printf("Approx normal = %.2f %.2f %.2f\n", approx_normal[0],
156 approx_normal[1], approx_normal[2]);
157 dot_prod = MAT3_DOT_PRODUCT(normals[n1], approx_normal);
158 printf("Dot product = %.4f\n", dot_prod); */
159 /* angle = acos(dot_prod); */
160 /* printf("Normal ANGLE = %.3f rads.\n", angle); */
162 /* if ( dot_prod < -0.5 ) {
163 glFrontFace( GL_CW );
165 glFrontFace( GL_CCW );
168 glBegin(GL_TRIANGLE_STRIP);
170 glNormal3d(normals[n1][0], normals[n1][1], normals[n1][2]);
171 glVertex3d(nodes[n1][0] - ref.x, nodes[n1][1] - ref.y,
172 nodes[n1][2] - ref.z);
174 glNormal3d(normals[n2][0], normals[n2][1], normals[n2][2]);
175 glVertex3d(nodes[n2][0] - ref.x, nodes[n2][1] - ref.y,
176 nodes[n2][2] - ref.z);
178 glNormal3d(normals[n3][0], normals[n3][1], normals[n3][2]);
179 glVertex3d(nodes[n3][0] - ref.x, nodes[n3][1] - ref.y,
180 nodes[n3][2] - ref.z);
183 glNormal3d(normals[n4][0], normals[n4][1], normals[n4][2]);
184 glVertex3d(nodes[n4][0] - ref.x, nodes[n4][1] - ref.y,
185 nodes[n4][2] - ref.z);
187 } else if ( line[0] == 'f' ) {
188 /* unoptimized face */
191 /* close out the previous structure and start the next */
197 glBegin(GL_TRIANGLES);
199 /* printf("new triangle = %s", line);*/
200 sscanf(line, "f %d %d %d\n", &n1, &n2, &n3);
202 glNormal3d(normals[n1][0], normals[n1][1], normals[n1][2]);
203 glVertex3d(nodes[n1][0] - ref.x, nodes[n1][1] - ref.y,
204 nodes[n1][2] - ref.z);
206 glNormal3d(normals[n2][0], normals[n2][1], normals[n2][2]);
207 glVertex3d(nodes[n2][0] - ref.x, nodes[n2][1] - ref.y,
208 nodes[n2][2] - ref.z);
210 glNormal3d(normals[n3][0], normals[n3][1], normals[n3][2]);
211 glVertex3d(nodes[n3][0] - ref.x, nodes[n3][1] - ref.y,
212 nodes[n3][2] - ref.z);
213 } else if ( line[0] == 'q' ) {
214 /* continue a triangle strip */
217 /* printf("continued tri strip = %s ", line); */
218 sscanf(line, "q %d %d\n", &n1, &n2);
219 /* printf("read %d %d\n", n1, n2); */
221 glNormal3d(normals[n1][0], normals[n1][1], normals[n1][2]);
222 glVertex3d(nodes[n1][0] - ref.x, nodes[n1][1] - ref.y,
223 nodes[n1][2] - ref.z);
226 /* printf(" (cont)\n"); */
227 glNormal3d(normals[n2][0], normals[n2][1], normals[n2][2]);
228 glVertex3d(nodes[n2][0] - ref.x, nodes[n2][1] - ref.y,
229 nodes[n2][2] - ref.z);
232 printf("Unknown line in %s = %s\n", path, line);
238 /* Draw normal vectors (for visually verifying normals)*/
241 glColor3f(0.0, 0.0, 0.0);
242 for ( i = 0; i < ncount; i++ ) {
243 glVertex3d(nodes[i][0] - ref.x,
245 nodes[i][2] - ref.z);
246 glVertex3d(nodes[i][0] - ref.x + 500*normals[i][0],
247 nodes[i][1] - ref.y + 500*normals[i][1],
248 nodes[i][2] - ref.z + 500*normals[i][2]);
262 /* Revision 1.9 1997/12/12 19:52:57 curt
263 /* Working on lightling and material properties.
265 * Revision 1.8 1997/12/10 01:19:51 curt
266 * Tweaks for verion 0.15 release.
268 * Revision 1.7 1997/12/08 22:51:17 curt
269 * Enhanced to handle ccw and cw tri-stripe winding. This is a temporary
270 * admission of defeat. I will eventually go back and get all the stripes
271 * wound the same way (ccw).
273 * Revision 1.6 1997/11/25 19:25:35 curt
274 * Changes to integrate Durk's moon/sun code updates + clean up.
276 * Revision 1.5 1997/11/15 18:16:39 curt
279 * Revision 1.4 1997/11/14 00:26:49 curt
280 * Transform scenery coordinates earlier in pipeline when scenery is being
281 * created, not when it is being loaded. Precalculate normals for each node
282 * as average of the normals of each containing polygon so Garoude shading is
285 * Revision 1.3 1997/10/31 04:49:12 curt
286 * Tweaking vertex orders.
288 * Revision 1.2 1997/10/30 12:38:45 curt
289 * Working on new scenery subsystem.
291 * Revision 1.1 1997/10/28 21:14:54 curt