/************************************************************************** * mesh.c -- data structures and routines for processing terrain meshes * * Written by Curtis Olson, started May 1997. * * Copyright (C) 1997 Curtis L. Olson - curt@infoplane.com * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of the * License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. * * $Id$ * (Log is kept at end of this file) **************************************************************************/ #ifndef __CYGWIN32__ # include #endif #ifdef WIN32 # include #endif #include #include /* atof(), atoi() */ #include #include #include #include #include #include #include #include #include #include #include /* Temporary hack until we get the scenery management system running */ extern GLint area_terrain; extern struct MESH eg; /* initialize the non-array mesh values */ void mesh_init(struct MESH *m) { m->originx = 0.0; m->originy = 0.0; m->rows = 0; m->cols = 0; m->row_step = 0.0; m->col_step = 0.0; m->cur_row = 0; m->cur_col = 0; m->do_data = 0; } /* return a pointer to a new mesh structure (no data array allocated yet) */ struct MESH *(new_mesh)( void ) { struct MESH *mesh_ptr; mesh_ptr = (struct MESH *)malloc(sizeof(struct MESH)); if ( mesh_ptr == 0 ) { printf("Virtual memory exceeded\n"); exit(-1); } mesh_ptr->cur_row = 0; mesh_ptr->cur_col = 0; return(mesh_ptr); } /* return a pointer to a dynamically allocated array */ float *(new_mesh_data)(int nrows, int ncols) { float *mesh_data_ptr; mesh_data_ptr = (float *)malloc(nrows * ncols * sizeof(float)); if ( mesh_data_ptr == 0 ) { printf("Virtual memory exceeded\n"); exit(-1); } printf("Allocated float(%d, %d)\n", nrows, ncols); return(mesh_data_ptr); } /* set the option name in the mesh data structure */ void mesh_set_option_name(struct MESH *m, char *name) { if ( strlen(name) < MAX_IDENT_LEN ) { strcpy(m->option_name, name); } else { strncpy(m->option_name, name, MAX_IDENT_LEN - 1); m->option_name[MAX_IDENT_LEN - 1] = '\0'; } if ( strcmp(m->option_name, "do_data") == 0 ) { m->do_data = 1; } else { m->do_data = 0; } } /* set an option value in the mesh data structure */ void mesh_set_option_value(struct MESH *m, char *value) { /* printf("Setting %s to %s\n", m->option_name, value); */ if ( m->do_data ) { /* mesh data is a pseudo 2d array */ /* printf("Setting mesh_data[%d][%d] to %s\n", m->cur_row, m->cur_col, value); */ m->mesh_data[m->cur_row * m->cols + m->cur_col] = atof(value); m->cur_col++; if ( m->cur_col >= m->cols ) { m->cur_col = 0; m->cur_row++; if ( m->cur_row > m->rows ) { m->do_data = 0; } } } else if ( strcmp(m->option_name, "origin_lon") == 0 ) { m->originx = atof(value); } else if ( strcmp(m->option_name, "origin_lat") == 0 ) { m->originy = atof(value); } else if ( strcmp(m->option_name, "rows") == 0 ) { m->rows = atoi(value); } else if ( strcmp(m->option_name, "cols") == 0 ) { m->cols = atoi(value); } else if ( strcmp(m->option_name, "row_step") == 0 ) { m->row_step = atof(value); } else if ( strcmp(m->option_name, "col_step") == 0 ) { m->col_step = atof(value); } else { printf("Unknown option %s with value %s, ignoring ...\n", m->option_name, value); } } /* do whatever needs to be done with the mesh now that it's been loaded, such as generating the OpenGL call list. */ void mesh_do_it(struct MESH *m) { area_terrain = mesh_to_OpenGL(m); } /* return the current altitude based on mesh data. We should rewrite * this to interpolate exact values, but for now this is good enough */ double mesh_altitude(double lon, double lat) { /* we expect incoming (lon,lat) to be in arcsec for now */ double xlocal, ylocal, dx, dy, zA, zB, elev; int x1, y1, z1, x2, y2, z2, x3, y3, z3; int xindex, yindex; int skip; skip = scenery.terrain_skip; /* determine if we are in the lower triangle or the upper triangle ______ | /| | / | | / | |/ | ------ then calculate our end points */ xlocal = (lon - eg.originx) / eg.col_step; ylocal = (lat - eg.originy) / eg.row_step; xindex = (int)(xlocal / skip) * skip; yindex = (int)(ylocal / skip) * skip; if ( (xindex < 0) || (xindex + skip >= eg.cols) || (yindex < 0) || (yindex + skip >= eg.rows) ) { return(-9999); } dx = xlocal - xindex; dy = ylocal - yindex; if ( dx > dy ) { /* lower triangle */ /* printf(" Lower triangle\n"); */ x1 = xindex; y1 = yindex; z1 = eg.mesh_data[y1 * eg.cols + x1]; x2 = xindex + skip; y2 = yindex; z2 = eg.mesh_data[y2 * eg.cols + x2]; x3 = xindex + skip; y3 = yindex + skip; z3 = eg.mesh_data[y3 * eg.cols + x3]; /* printf(" dx = %.2f dy = %.2f\n", dx, dy); printf(" (x1,y1,z1) = (%d,%d,%d)\n", x1, y1, z1); printf(" (x2,y2,z2) = (%d,%d,%d)\n", x2, y2, z2); printf(" (x3,y3,z3) = (%d,%d,%d)\n", x3, y3, z3); */ zA = dx * (z2 - z1) / skip + z1; zB = dx * (z3 - z1) / skip + z1; /* printf(" zA = %.2f zB = %.2f\n", zA, zB); */ if ( dx > FG_EPSILON ) { elev = dy * (zB - zA) / dx + zA; } else { elev = zA; } } else { /* upper triangle */ /* printf(" Upper triangle\n"); */ x1 = xindex; y1 = yindex; z1 = eg.mesh_data[y1 * eg.cols + x1]; x2 = xindex; y2 = yindex + skip; z2 = eg.mesh_data[y2 * eg.cols + x2]; x3 = xindex + skip; y3 = yindex + skip; z3 = eg.mesh_data[y3 * eg.cols + x3]; /* printf(" dx = %.2f dy = %.2f\n", dx, dy); printf(" (x1,y1,z1) = (%d,%d,%d)\n", x1, y1, z1); printf(" (x2,y2,z2) = (%d,%d,%d)\n", x2, y2, z2); printf(" (x3,y3,z3) = (%d,%d,%d)\n", x3, y3, z3); */ zA = dy * (z2 - z1) / skip + z1; zB = dy * (z3 - z1) / skip + z1; /* printf(" zA = %.2f zB = %.2f\n", zA, zB ); printf(" xB - xA = %.2f\n", eg.col_step * dy / eg.row_step); */ if ( dy > FG_EPSILON ) { elev = dx * (zB - zA) / dy + zA; } else { elev = zA; } } return(elev); } /* walk through mesh and make opengl calls */ GLint mesh_to_OpenGL(struct MESH *m) { GLint mesh; /* static GLfloat color[4] = { 0.5, 0.4, 0.25, 1.0 }; */ /* dark desert */ /* static GLfloat color[4] = { 0.5, 0.5, 0.25, 1.0 }; */ static GLfloat color[4] = { 1.0, 0.0, 0.0, 1.0 }; double centerx, centery; double randx, randy; float x1, y1, x2, y2, z11, z12, z21, z22; struct fgCartesianPoint p11, p12, p21, p22, c; double gc_lon, gc_lat, sl_radius; MAT3vec v1, v2, normal; int i, j, istep, jstep, iend, jend; float temp; printf("In mesh2GL(), generating GL call list.\n"); /* Detail level. This is how big a step we take as we walk * through the DEM data set. This value is initialized in * .../Scenery/scenery.c:fgSceneryInit() */ istep = jstep = scenery.terrain_skip ; centerx = m->originx + (m->rows * m->row_step) / 2.0; centery = m->originy + (m->cols * m->col_step) / 2.0; fgGeodToGeoc(centery*ARCSEC_TO_RAD, 0, &sl_radius, &gc_lat); c = fgPolarToCart(centerx*ARCSEC_TO_RAD, gc_lat, sl_radius); scenery.center = c; mesh = glGenLists(1); glNewList(mesh, GL_COMPILE); /* glMaterialfv( GL_FRONT, GL_AMBIENT_AND_DIFFUSE, color ); */ glColor3fv(color); iend = m->cols - 1; jend = m->rows - 1; y1 = m->originy; y2 = y1 + (m->col_step * istep); for ( i = 0; i < iend; i += istep ) { x1 = m->originx; x2 = x1 + (m->row_step * jstep); glBegin(GL_TRIANGLE_STRIP); for ( j = 0; j < jend; j += jstep ) { z11 = m->mesh_data[i * m->cols + j ]; z12 = m->mesh_data[(i+istep) * m->cols + j ]; z21 = m->mesh_data[i * m->cols + (j+jstep)]; z22 = m->mesh_data[(i+istep) * m->cols + (j+jstep)]; /* printf("A geodetic point is (%.2f, %.2f, %.2f)\n", x1, y1, z11); */ gc_lon = x1*ARCSEC_TO_RAD; fgGeodToGeoc(y1*ARCSEC_TO_RAD, z11, &sl_radius, &gc_lat); /* printf("A geocentric point is (%.2f, %.2f, %.2f)\n", gc_lon, gc_lat, sl_radius+z11); */ p11 = fgPolarToCart(gc_lon, gc_lat, sl_radius+z11); /* printf("A cart point is (%.8f, %.8f, %.8f)\n", p11.x, p11.y, p11.z); */ gc_lon = x1*ARCSEC_TO_RAD; fgGeodToGeoc(y2*ARCSEC_TO_RAD, z12, &sl_radius, &gc_lat); p12 = fgPolarToCart(gc_lon, gc_lat, sl_radius+z12); gc_lon = x2*ARCSEC_TO_RAD; fgGeodToGeoc(y1*ARCSEC_TO_RAD, z21, &sl_radius, &gc_lat); p21 = fgPolarToCart(gc_lon, gc_lat, sl_radius+z21); gc_lon = x2*ARCSEC_TO_RAD; fgGeodToGeoc(y2*ARCSEC_TO_RAD, z22, &sl_radius, &gc_lat); p22 = fgPolarToCart(gc_lon, gc_lat, sl_radius+z22); v1[0] = p22.y - p11.y; v1[1] = p22.z - p11.z; v1[2] = z22 - z11; v2[0] = p12.y - p11.y; v2[1] = p12.z - p11.z; v2[2] = z12 - z11; MAT3cross_product(normal, v1, v2); MAT3_NORMALIZE_VEC(normal,temp); glNormal3d(normal[0], normal[1], normal[2]); /* printf("normal 1 = (%.2f %.2f %.2f\n", normal[0], normal[1], normal[2]); */ if ( j == 0 ) { /* first time through */ glVertex3d(p12.x - c.x, p12.y - c.y, p12.z - c.z); glVertex3d(p11.x - c.x, p11.y - c.y, p11.z - c.z); } glVertex3d(p22.x - c.x, p22.y - c.y, p22.z - c.z); v2[0] = p21.y - p11.y; v2[1] = p21.z - p11.z; v2[2] = z21 - z11; MAT3cross_product(normal, v2, v1); MAT3_NORMALIZE_VEC(normal,temp); glNormal3d(normal[0], normal[1], normal[2]); /* printf("normal 2 = (%.2f %.2f %.2f\n", normal[0], normal[1], normal[2]); */ glVertex3d(p21.x - c.x, p21.y - c.y, p21.z - c.z); x1 += m->row_step * jstep; x2 += m->row_step * jstep; } glEnd(); y1 += m->col_step * istep; y2 += m->col_step * istep; } /* this will go, it's only here for testing/debugging */ for ( i = 0; i < 200; i++ ) { randx = fg_random() * 3600.0; randy = fg_random() * 3600.0; /* mesh_make_test_object(m->originx + randx, m->originy + randy); */ } glEndList(); return(mesh); } /* $Log$ /* Revision 1.27 1998/01/19 19:27:15 curt /* Merged in make system changes from Bob Kuehne /* This should simplify things tremendously. /* * Revision 1.26 1998/01/19 18:40:36 curt * Tons of little changes to clean up the code and to remove fatal errors * when building with the c++ compiler. * * Revision 1.25 1998/01/07 03:31:27 curt * Miscellaneous tweaks. * * Revision 1.24 1997/12/15 23:54:59 curt * Add xgl wrappers for debugging. * Generate terrain normals on the fly. * * Revision 1.23 1997/10/30 12:38:44 curt * Working on new scenery subsystem. * * Revision 1.22 1997/10/28 21:00:21 curt * Changing to new terrain format. * * Revision 1.21 1997/08/27 03:30:27 curt * Changed naming scheme of basic shared structures. * * Revision 1.20 1997/08/19 23:55:08 curt * Worked on better simulating real lighting. * * Revision 1.19 1997/08/06 00:24:28 curt * Working on correct real time sun lighting. * * Revision 1.18 1997/08/02 19:10:14 curt * Incorporated mesh2GL.c into mesh.c * * Revision 1.17 1997/07/18 23:41:26 curt * Tweaks for building with Cygnus Win32 compiler. * * Revision 1.16 1997/07/16 20:04:51 curt * Minor tweaks to aid Win32 port. * * Revision 1.15 1997/07/14 16:26:04 curt * Testing/playing -- placed objects randomly across the entire terrain. * * Revision 1.14 1997/07/12 04:01:14 curt * Added #include to help Win32 compiling. * * Revision 1.13 1997/07/12 02:27:11 curt * Looking at potential scenery transformation/coordinate system problems. * * Revision 1.12 1997/07/11 03:23:19 curt * Solved some scenery display/orientation problems. Still have a positioning * (or transformation?) problem. * * Revision 1.11 1997/07/11 01:30:02 curt * More tweaking of terrian floor. * * Revision 1.10 1997/07/10 04:26:38 curt * We now can interpolated ground elevation for any position in the grid. We * can use this to enforce a "hard" ground. We still need to enforce some * bounds checking so that we don't try to lookup data points outside the * grid data set. * * Revision 1.9 1997/07/10 02:22:10 curt * Working on terrain elevation interpolation routine. * * Revision 1.8 1997/07/09 21:31:15 curt * Working on making the ground "hard." * * Revision 1.7 1997/07/08 18:20:13 curt * Working on establishing a hard ground. * * Revision 1.6 1997/06/29 21:16:49 curt * More twiddling with the Scenery Management system. * * Revision 1.5 1997/06/22 21:44:41 curt * Working on intergrating the VRML (subset) parser. * * Revision 1.4 1997/05/30 19:30:17 curt * The LaRCsim flight model is starting to look like it is working. * * Revision 1.3 1997/05/23 15:40:41 curt * Added GNU copyright headers. * * Revision 1.2 1997/05/19 18:20:50 curt * Slight change to origin key words. * * Revision 1.1 1997/05/16 16:07:04 curt * Initial revision. * */