240 lines
6.9 KiB
C
240 lines
6.9 KiB
C
/**************************************************************************
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* obj.c -- routines to handle WaveFront .obj format files.
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*
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* Written by Curtis Olson, started October 1997.
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*
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* Copyright (C) 1997 Curtis L. Olson - curt@infoplane.com
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* $Id$
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* (Log is kept at end of this file)
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**************************************************************************/
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#ifdef WIN32
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# include <windows.h>
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#endif
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#include <stdio.h>
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#include <string.h>
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#include <GL/glut.h>
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#include "obj.h"
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#include "scenery.h"
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#include "../Math/mat3.h"
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#define MAXNODES 100000
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float nodes[MAXNODES][3];
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float normals[MAXNODES][3];
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/* Load a .obj file and generate the GL call list */
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GLint fgObjLoad(char *path) {
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char line[256];
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static GLfloat color[4] = { 0.5, 0.5, 0.25, 1.0 };
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double v1[3], v2[3], approx_normal[3], dot_prod, temp;
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struct fgCartesianPoint ref;
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GLint area;
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FILE *f;
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int first, ncount, vncount, n1, n2, n3, n4;
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if ( (f = fopen(path, "r")) == NULL ) {
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printf("Cannot open file: %s\n", path);
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exit(-1);
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}
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area = glGenLists(1);
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glNewList(area, GL_COMPILE);
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/* glMaterialfv( GL_FRONT, GL_AMBIENT_AND_DIFFUSE, color ); */
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glColor3fv(color);
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first = 1;
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ncount = 1;
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vncount = 1;
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while ( fgets(line, 250, f) != NULL ) {
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if ( line[0] == '#' ) {
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/* comment -- ignore */
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} else if ( strncmp(line, "v ", 2) == 0 ) {
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/* node (vertex) */
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if ( ncount < MAXNODES ) {
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/* printf("vertex = %s", line); */
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sscanf(line, "v %f %f %f\n",
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&nodes[ncount][0], &nodes[ncount][1], &nodes[ncount][2]);
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if ( ncount == 1 ) {
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/* first node becomes the reference point */
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ref.x = nodes[ncount][0];
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ref.y = nodes[ncount][1];
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ref.z = nodes[ncount][2];
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scenery.center = ref;
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}
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ncount++;
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} else {
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printf("Read too many nodes ... dying :-(\n");
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exit(-1);
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}
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} else if ( strncmp(line, "vn ", 3) == 0 ) {
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/* vertex normal */
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if ( vncount < MAXNODES ) {
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/* printf("vertex normal = %s", line); */
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sscanf(line, "vn %f %f %f\n",
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&normals[vncount][0], &normals[vncount][1],
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&normals[vncount][2]);
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vncount++;
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} else {
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printf("Read too many vertex normals ... dying :-(\n");
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exit(-1);
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}
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} else if ( line[0] == 't' ) {
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/* start a new triangle strip */
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n1 = n2 = n3 = n4 = 0;
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if ( !first ) {
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/* close out the previous structure and start the next */
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glEnd();
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} else {
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first = 0;
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}
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glBegin(GL_TRIANGLE_STRIP);
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/* printf("new tri strip = %s", line); */
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sscanf(line, "t %d %d %d %d\n", &n1, &n2, &n3, &n4);
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/* printf("(t) = "); */
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/* try to get the proper rotation by calculating an
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* approximate normal and seeing if it is close to the
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* precalculated normal */
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v1[0] = nodes[n2][0] - nodes[n1][0];
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v1[1] = nodes[n2][1] - nodes[n1][1];
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v1[2] = nodes[n2][2] - nodes[n1][2];
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v2[0] = nodes[n3][0] - nodes[n1][0];
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v2[1] = nodes[n3][1] - nodes[n1][1];
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v2[2] = nodes[n3][2] - nodes[n1][2];
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MAT3cross_product(approx_normal, v1, v2);
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MAT3_NORMALIZE_VEC(approx_normal,temp);
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printf("Approx normal = %.2f %.2f %.2f\n", approx_normal[0],
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approx_normal[1], approx_normal[2]);
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dot_prod = MAT3_DOT_PRODUCT(normals[n1], approx_normal);
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printf("Dot product = %.4f\n", dot_prod);
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/* angle = acos(dot_prod); */
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/* printf("Normal ANGLE = %.3f rads.\n", angle); */
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glNormal3d(normals[n1][0], normals[n1][1], normals[n1][2]);
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glVertex3d(nodes[n1][0] - ref.x, nodes[n1][1] - ref.y,
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nodes[n1][2] - ref.z);
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glNormal3d(normals[n2][0], normals[n2][1], normals[n2][2]);
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glVertex3d(nodes[n2][0] - ref.x, nodes[n2][1] - ref.y,
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nodes[n2][2] - ref.z);
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glNormal3d(normals[n3][0], normals[n3][1], normals[n3][2]);
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glVertex3d(nodes[n3][0] - ref.x, nodes[n3][1] - ref.y,
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nodes[n3][2] - ref.z);
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if ( n4 > 0 ) {
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glNormal3d(normals[n4][0], normals[n4][1], normals[n4][2]);
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glVertex3d(nodes[n4][0] - ref.x, nodes[n4][1] - ref.y,
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nodes[n4][2] - ref.z);
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}
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} else if ( line[0] == 'f' ) {
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/* unoptimized face */
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if ( !first ) {
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/* close out the previous structure and start the next */
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glEnd();
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} else {
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first = 0;
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}
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glBegin(GL_TRIANGLES);
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/* printf("new triangle = %s", line);*/
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sscanf(line, "f %d %d %d\n", &n1, &n2, &n3);
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glNormal3d(normals[n1][0], normals[n1][1], normals[n1][2]);
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glVertex3d(nodes[n1][0] - ref.x, nodes[n1][1] - ref.y,
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nodes[n1][2] - ref.z);
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glNormal3d(normals[n2][0], normals[n2][1], normals[n2][2]);
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glVertex3d(nodes[n2][0] - ref.x, nodes[n2][1] - ref.y,
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nodes[n2][2] - ref.z);
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glNormal3d(normals[n3][0], normals[n3][1], normals[n3][2]);
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glVertex3d(nodes[n3][0] - ref.x, nodes[n3][1] - ref.y,
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nodes[n3][2] - ref.z);
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} else if ( line[0] == 'q' ) {
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/* continue a triangle strip */
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n1 = n2 = 0;
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/* printf("continued tri strip = %s ", line); */
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sscanf(line, "q %d %d\n", &n1, &n2);
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/* printf("read %d %d\n", n1, n2); */
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glNormal3d(normals[n1][0], normals[n1][1], normals[n1][2]);
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glVertex3d(nodes[n1][0] - ref.x, nodes[n1][1] - ref.y,
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nodes[n1][2] - ref.z);
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if ( n2 > 0 ) {
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/* printf(" (cont)\n"); */
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glNormal3d(normals[n2][0], normals[n2][1], normals[n2][2]);
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glVertex3d(nodes[n2][0] - ref.x, nodes[n2][1] - ref.y,
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nodes[n2][2] - ref.z);
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}
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} else {
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printf("Unknown line in %s = %s\n", path, line);
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}
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}
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glEnd();
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glEndList();
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fclose(f);
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return(area);
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}
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/* $Log$
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/* Revision 1.6 1997/11/25 19:25:35 curt
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/* Changes to integrate Durk's moon/sun code updates + clean up.
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/*
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* Revision 1.5 1997/11/15 18:16:39 curt
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* minor tweaks.
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*
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* Revision 1.4 1997/11/14 00:26:49 curt
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* Transform scenery coordinates earlier in pipeline when scenery is being
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* created, not when it is being loaded. Precalculate normals for each node
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* as average of the normals of each containing polygon so Garoude shading is
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* now supportable.
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*
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* Revision 1.3 1997/10/31 04:49:12 curt
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* Tweaking vertex orders.
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*
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* Revision 1.2 1997/10/30 12:38:45 curt
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* Working on new scenery subsystem.
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*
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* Revision 1.1 1997/10/28 21:14:54 curt
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* Initial revision.
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*
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*/
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