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 color[4] = { 0.5, 0.5, 0.25, 1.0 };
52 double v1[3], v2[3], approx_normal[3], dot_prod, temp;
53 struct fgCartesianPoint ref;
56 int first, ncount, vncount, n1, n2, n3, n4;
59 if ( (f = fopen(path, "r")) == NULL ) {
60 printf("Cannot open file: %s\n", path);
65 glNewList(area, GL_COMPILE);
67 /* glMaterialfv( GL_FRONT, GL_AMBIENT_AND_DIFFUSE, color ); */
74 while ( fgets(line, 250, f) != NULL ) {
75 if ( line[0] == '#' ) {
76 /* comment -- ignore */
77 } else if ( strncmp(line, "v ", 2) == 0 ) {
79 if ( ncount < MAXNODES ) {
80 /* printf("vertex = %s", line); */
81 sscanf(line, "v %f %f %f\n",
82 &nodes[ncount][0], &nodes[ncount][1], &nodes[ncount][2]);
84 /* first node becomes the reference point */
85 ref.x = nodes[ncount][0];
86 ref.y = nodes[ncount][1];
87 ref.z = nodes[ncount][2];
92 printf("Read too many nodes ... dying :-(\n");
95 } else if ( strncmp(line, "vn ", 3) == 0 ) {
97 if ( vncount < MAXNODES ) {
98 /* printf("vertex normal = %s", line); */
99 sscanf(line, "vn %f %f %f\n",
100 &normals[vncount][0], &normals[vncount][1],
101 &normals[vncount][2]);
104 printf("Read too many vertex normals ... dying :-(\n");
107 } else if ( strncmp(line, "winding ", 8) == 0 ) {
108 sscanf(line+8, "%s", winding);
109 printf("WINDING = %s\n", winding);
111 /* can't call glFrontFace() between glBegin() & glEnd() */
115 if ( strcmp(winding, "cw") == 0 ) {
116 glFrontFace( GL_CW );
118 glFrontFace ( GL_CCW );
120 } else if ( line[0] == 't' ) {
121 /* start a new triangle strip */
123 n1 = n2 = n3 = n4 = 0;
126 /* close out the previous structure and start the next */
132 /* printf("new tri strip = %s", line); */
133 sscanf(line, "t %d %d %d %d\n", &n1, &n2, &n3, &n4);
135 /* printf("(t) = "); */
137 /* try to get the proper rotation by calculating an
138 * approximate normal and seeing if it is close to the
139 * precalculated normal */
140 /*v1[0] = nodes[n2][0] - nodes[n1][0];
141 v1[1] = nodes[n2][1] - nodes[n1][1];
142 v1[2] = nodes[n2][2] - nodes[n1][2];
143 v2[0] = nodes[n3][0] - nodes[n1][0];
144 v2[1] = nodes[n3][1] - nodes[n1][1];
145 v2[2] = nodes[n3][2] - nodes[n1][2];
146 MAT3cross_product(approx_normal, v1, v2);
147 MAT3_NORMALIZE_VEC(approx_normal,temp);
148 printf("Approx normal = %.2f %.2f %.2f\n", approx_normal[0],
149 approx_normal[1], approx_normal[2]);
150 dot_prod = MAT3_DOT_PRODUCT(normals[n1], approx_normal);
151 printf("Dot product = %.4f\n", dot_prod); */
152 /* angle = acos(dot_prod); */
153 /* printf("Normal ANGLE = %.3f rads.\n", angle); */
155 /* if ( dot_prod < -0.5 ) {
156 glFrontFace( GL_CW );
158 glFrontFace( GL_CCW );
161 glBegin(GL_TRIANGLE_STRIP);
163 glNormal3d(normals[n1][0], normals[n1][1], normals[n1][2]);
164 glVertex3d(nodes[n1][0] - ref.x, nodes[n1][1] - ref.y,
165 nodes[n1][2] - ref.z);
167 glNormal3d(normals[n2][0], normals[n2][1], normals[n2][2]);
168 glVertex3d(nodes[n2][0] - ref.x, nodes[n2][1] - ref.y,
169 nodes[n2][2] - ref.z);
171 glNormal3d(normals[n3][0], normals[n3][1], normals[n3][2]);
172 glVertex3d(nodes[n3][0] - ref.x, nodes[n3][1] - ref.y,
173 nodes[n3][2] - ref.z);
176 glNormal3d(normals[n4][0], normals[n4][1], normals[n4][2]);
177 glVertex3d(nodes[n4][0] - ref.x, nodes[n4][1] - ref.y,
178 nodes[n4][2] - ref.z);
180 } else if ( line[0] == 'f' ) {
181 /* unoptimized face */
184 /* close out the previous structure and start the next */
190 glBegin(GL_TRIANGLES);
192 /* printf("new triangle = %s", line);*/
193 sscanf(line, "f %d %d %d\n", &n1, &n2, &n3);
195 glNormal3d(normals[n1][0], normals[n1][1], normals[n1][2]);
196 glVertex3d(nodes[n1][0] - ref.x, nodes[n1][1] - ref.y,
197 nodes[n1][2] - ref.z);
199 glNormal3d(normals[n2][0], normals[n2][1], normals[n2][2]);
200 glVertex3d(nodes[n2][0] - ref.x, nodes[n2][1] - ref.y,
201 nodes[n2][2] - ref.z);
203 glNormal3d(normals[n3][0], normals[n3][1], normals[n3][2]);
204 glVertex3d(nodes[n3][0] - ref.x, nodes[n3][1] - ref.y,
205 nodes[n3][2] - ref.z);
206 } else if ( line[0] == 'q' ) {
207 /* continue a triangle strip */
210 /* printf("continued tri strip = %s ", line); */
211 sscanf(line, "q %d %d\n", &n1, &n2);
212 /* printf("read %d %d\n", n1, n2); */
214 glNormal3d(normals[n1][0], normals[n1][1], normals[n1][2]);
215 glVertex3d(nodes[n1][0] - ref.x, nodes[n1][1] - ref.y,
216 nodes[n1][2] - ref.z);
219 /* printf(" (cont)\n"); */
220 glNormal3d(normals[n2][0], normals[n2][1], normals[n2][2]);
221 glVertex3d(nodes[n2][0] - ref.x, nodes[n2][1] - ref.y,
222 nodes[n2][2] - ref.z);
225 printf("Unknown line in %s = %s\n", path, line);
231 /* Draw normal vectors (for visually verifying normals)*/
232 /* glBegin(GL_LINES); */
233 /* glColor3f(0.0, 0.0, 0.0); */
234 /* for ( i = 0; i < ncount; i++ ) { */
235 /* glVertex3d(nodes[i][0] - ref.x, */
236 /* nodes[i][1] - ref.y, */
237 /* nodes[i][2] - ref.z); */
238 /* glVertex3d(nodes[i][0] - ref.x + 1000*normals[i][0], */
239 /* nodes[i][1] - ref.y + 1000*normals[i][1], */
240 /* nodes[i][2] - ref.z + 1000*normals[i][2]); */
253 /* Revision 1.7 1997/12/08 22:51:17 curt
254 /* Enhanced to handle ccw and cw tri-stripe winding. This is a temporary
255 /* admission of defeat. I will eventually go back and get all the stripes
256 /* wound the same way (ccw).
258 * Revision 1.6 1997/11/25 19:25:35 curt
259 * Changes to integrate Durk's moon/sun code updates + clean up.
261 * Revision 1.5 1997/11/15 18:16:39 curt
264 * Revision 1.4 1997/11/14 00:26:49 curt
265 * Transform scenery coordinates earlier in pipeline when scenery is being
266 * created, not when it is being loaded. Precalculate normals for each node
267 * as average of the normals of each containing polygon so Garoude shading is
270 * Revision 1.3 1997/10/31 04:49:12 curt
271 * Tweaking vertex orders.
273 * Revision 1.2 1997/10/30 12:38:45 curt
274 * Working on new scenery subsystem.
276 * Revision 1.1 1997/10/28 21:14:54 curt