156 lines
4.4 KiB
C
156 lines
4.4 KiB
C
/**************************************************************************
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* mesh2GL.c -- walk through a mesh data structure and make GL calls
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*
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* Written by Curtis Olson, started May 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 GLUT
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#include <GL/glut.h>
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#elif TIGER
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/* assumes -I/usr/include/mesa in compile command */
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#include "gltk.h"
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#endif
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#include "../scenery/mesh.h"
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#include "mat3.h"
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/* Sets the first vector to be the cross-product of the last two
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vectors. */
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static void mat3_cross_product(float result_vec[3], register float vec1[3],
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register float vec2[3]) {
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float tempvec[3];
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register float *temp = tempvec;
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temp[0] = vec1[1] * vec2[2] - vec1[2] * vec2[1];
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temp[1] = vec1[2] * vec2[0] - vec1[0] * vec2[2];
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temp[2] = vec1[0] * vec2[1] - vec1[1] * vec2[0];
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MAT3_COPY_VEC(result_vec, temp);
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}
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/* walk through mesh and make ogl calls */
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GLint mesh2GL(struct mesh *m) {
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GLint mesh;
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float x1, y1, x2, y2, z11, z12, z21, z22;
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float v1[3], v2[3], normal[3];
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int i, j, istep, jstep, iend, jend;
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float temp;
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istep = jstep = 4; /* Detail level 1 -- 1200 ... */
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mesh = glGenLists(1);
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glNewList(mesh, GL_COMPILE);
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iend = m->cols - 1;
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jend = m->rows - 1;
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y1 = m->originy;
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y2 = y1 + (m->col_step * istep);
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for ( i = 0; i < iend; i += istep ) {
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x1 = m->originx;
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x2 = x1 + (m->row_step * jstep);
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glBegin(GL_TRIANGLE_STRIP);
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for ( j = 0; j < jend; j += jstep ) {
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z11 = 0.03 * m->mesh_data[j * m->rows + i ];
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z12 = 0.03 * m->mesh_data[j * m->rows + (i+istep)];
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z21 = 0.03 * m->mesh_data[(j+jstep) * m->rows + i ];
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z22 = 0.03 * m->mesh_data[(j+jstep) * m->rows + (i+istep)];
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v1[0] = x2 - x1; v1[1] = 0; v1[2] = z21 - z11;
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v2[0] = 0; v2[1] = y2 - y1; v2[2] = z12 - z11;
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mat3_cross_product(normal, v1, v2);
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MAT3_NORMALIZE_VEC(normal,temp);
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glNormal3fv(normal);
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if ( j == 0 ) {
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/* first time through */
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glVertex3f(x1, y1, z11);
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glVertex3f(x1, y2, z12);
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}
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glVertex3f(x2, y1, z21);
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v1[0] = x2 - x1; v1[1] = y1 - y2; v1[2] = z21 - z12;
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v2[0] = x2 - x1; v2[1] = 0; v2[2] = z22 - z12;
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mat3_cross_product(normal, v1, v2);
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MAT3_NORMALIZE_VEC(normal,temp);
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glNormal3fv(normal);
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glVertex3f(x2, y2, z22);
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x1 = x2;
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x2 = x1 + (m->row_step * jstep);
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}
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glEnd();
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y1 = y2;
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y2 = y1 + (m->col_step * istep);
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}
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glEndList();
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return(mesh);
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}
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/* $Log$
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/* Revision 1.7 1997/05/29 02:33:24 curt
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/* Updated to reflect changing interfaces in other "modules."
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/*
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* Revision 1.6 1997/05/27 17:44:32 curt
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* Renamed & rearranged variables and routines. Added some initial simple
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* timer/alarm routines so the flight model can be updated on a regular
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* interval.
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*
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* Revision 1.5 1997/05/24 01:45:32 curt
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* Fixed surface normals for triangle mesh.
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*
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* Revision 1.4 1997/05/23 20:05:24 curt
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* First stab at using GL_TRIANGLE_STRIP's instead of GL_POLYGONS (to conserve
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* memory)
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*
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* Revision 1.3 1997/05/23 15:40:26 curt
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* Added GNU copyright headers.
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* Fog now works!
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*
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* Revision 1.2 1997/05/23 00:35:13 curt
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* Trying to get fog to work ...
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*
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* Revision 1.1 1997/05/21 15:57:52 curt
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* Renamed due to added GLUT support.
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*
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* Revision 1.3 1997/05/19 18:22:42 curt
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* Parameter tweaking ... starting to stub in fog support.
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*
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* Revision 1.2 1997/05/17 00:17:35 curt
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* Trying to stub in support for standard OpenGL.
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*
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* Revision 1.1 1997/05/16 16:05:52 curt
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* Initial revision.
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*
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*/
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