1 /**************************************************************************
2 * mesh2GL.c -- walk through a mesh data structure and make GL calls
4 * Written by Curtis Olson, started May 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 **************************************************************************/
30 /* assumes -I/usr/include/mesa in compile command */
34 #include "../scenery/mesh.h"
38 /* Sets the first vector to be the cross-product of the last two
40 static void mat3_cross_product(float result_vec[3], register float vec1[3],
41 register float vec2[3]) {
43 register float *temp = tempvec;
45 temp[0] = vec1[1] * vec2[2] - vec1[2] * vec2[1];
46 temp[1] = vec1[2] * vec2[0] - vec1[0] * vec2[2];
47 temp[2] = vec1[0] * vec2[1] - vec1[1] * vec2[0];
49 MAT3_COPY_VEC(result_vec, temp);
53 /* walk through mesh and make ogl calls */
54 GLint mesh2GL(struct mesh *m) {
57 float x1, y1, x2, y2, z11, z12, z21, z22;
58 float v1[3], v2[3], normal[3];
59 int i, j, istep, jstep, iend, jend;
62 istep = jstep = 8; /* Detail level 1 -- 1200 ... */
65 glNewList(mesh, GL_COMPILE);
71 y2 = y1 + (m->col_step * istep);
73 for ( i = 0; i < iend; i += istep ) {
75 x2 = x1 + (m->row_step * jstep);
77 glBegin(GL_TRIANGLE_STRIP);
79 for ( j = 0; j < jend; j += jstep ) {
80 z11 = 0.03 * m->mesh_data[j * m->rows + i ];
81 z12 = 0.03 * m->mesh_data[j * m->rows + (i+istep)];
82 z21 = 0.03 * m->mesh_data[(j+jstep) * m->rows + i ];
83 z22 = 0.03 * m->mesh_data[(j+jstep) * m->rows + (i+istep)];
85 v1[0] = x2 - x1; v1[1] = 0; v1[2] = z21 - z11;
86 v2[0] = 0; v2[1] = y2 - y1; v2[2] = z12 - z11;
87 mat3_cross_product(normal, v1, v2);
88 MAT3_NORMALIZE_VEC(normal,temp);
92 /* first time through */
93 glVertex3f(x1, y1, z11);
94 glVertex3f(x1, y2, z12);
97 glVertex3f(x2, y1, z21);
99 v1[0] = x2 - x1; v1[1] = y1 - y2; v1[2] = z21 - z12;
100 v2[0] = x2 - x1; v2[1] = 0; v2[2] = z22 - z12;
101 mat3_cross_product(normal, v1, v2);
102 MAT3_NORMALIZE_VEC(normal,temp);
104 glVertex3f(x2, y2, z22);
107 x2 = x1 + (m->row_step * jstep);
112 y2 = y1 + (m->col_step * istep);
122 /* Revision 1.8 1997/05/29 12:31:40 curt
123 /* Minor tweaks, moving towards general flight model integration.
125 * Revision 1.7 1997/05/29 02:33:24 curt
126 * Updated to reflect changing interfaces in other "modules."
128 * Revision 1.6 1997/05/27 17:44:32 curt
129 * Renamed & rearranged variables and routines. Added some initial simple
130 * timer/alarm routines so the flight model can be updated on a regular
133 * Revision 1.5 1997/05/24 01:45:32 curt
134 * Fixed surface normals for triangle mesh.
136 * Revision 1.4 1997/05/23 20:05:24 curt
137 * First stab at using GL_TRIANGLE_STRIP's instead of GL_POLYGONS (to conserve
140 * Revision 1.3 1997/05/23 15:40:26 curt
141 * Added GNU copyright headers.
144 * Revision 1.2 1997/05/23 00:35:13 curt
145 * Trying to get fog to work ...
147 * Revision 1.1 1997/05/21 15:57:52 curt
148 * Renamed due to added GLUT support.
150 * Revision 1.3 1997/05/19 18:22:42 curt
151 * Parameter tweaking ... starting to stub in fog support.
153 * Revision 1.2 1997/05/17 00:17:35 curt
154 * Trying to stub in support for standard OpenGL.
156 * Revision 1.1 1997/05/16 16:05:52 curt