1 /**************************************************************************
2 * tilecache.c -- routines to handle scenery tile caching
4 * Written by Curtis Olson, started January 1998.
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 **************************************************************************/
34 #include <Include/general.h>
35 #include <Main/fg_debug.h>
36 #include <Main/views.h>
37 #include <Scenery/bucketutils.h>
38 #include <Scenery/obj.h>
39 #include <Scenery/tilecache.h>
43 struct fgTILE tile_cache[FG_TILE_CACHE_SIZE];
46 /* Initialize the tile cache subsystem */
47 void fgTileCacheInit( void ) {
50 fgPrintf(FG_TERRAIN, FG_INFO, "Initializing the tile cache.\n");
52 for ( i = 0; i < FG_TILE_CACHE_SIZE; i++ ) {
53 tile_cache[i].used = 0;
58 /* Search for the specified "bucket" in the cache */
59 int fgTileCacheExists( struct fgBUCKET *p ) {
62 for ( i = 0; i < FG_TILE_CACHE_SIZE; i++ ) {
63 if ( tile_cache[i].tile_bucket.lon == p->lon ) {
64 if ( tile_cache[i].tile_bucket.lat == p->lat ) {
65 if ( tile_cache[i].tile_bucket.x == p->x ) {
66 if ( tile_cache[i].tile_bucket.y == p->y ) {
67 fgPrintf( FG_TERRAIN, FG_DEBUG,
68 "TILE EXISTS in cache ... index = %d\n", i );
80 /* Fill in a tile cache entry with real data for the specified bucket */
81 void fgTileCacheEntryFillIn( int index, struct fgBUCKET *p ) {
88 /* Mark this cache entry as used */
89 tile_cache[index].used = 1;
91 /* Update the bucket */
92 tile_cache[index].tile_bucket.lon = p->lon;
93 tile_cache[index].tile_bucket.lat = p->lat;
94 tile_cache[index].tile_bucket.x = p->x;
95 tile_cache[index].tile_bucket.y = p->y;
97 /* Load the appropriate area and get the display list pointer */
98 fgBucketGenBasePath(p, base_path);
99 sprintf(file_name, "%s/Scenery/%s/%ld.obj", g->root_dir,
100 base_path, fgBucketGenIndex(p));
101 tile_cache[index].display_list =
102 fgObjLoad(file_name, &tile_cache[index].local_ref,
103 &tile_cache[index].bounding_radius);
107 /* Free a tile cache entry */
108 void fgTileCacheEntryFree( int index ) {
109 /* Mark this cache entry as un-used */
110 tile_cache[index].used = 0;
112 /* Update the bucket */
113 fgPrintf( FG_TERRAIN, FG_DEBUG,
114 "FREEING TILE = (%d %d %d %d)\n",
115 tile_cache[index].tile_bucket.lon,
116 tile_cache[index].tile_bucket.lat,
117 tile_cache[index].tile_bucket.x,
118 tile_cache[index].tile_bucket.y );
120 /* Load the appropriate area and get the display list pointer */
121 xglDeleteLists( tile_cache[index].display_list, 1 );
125 /* Return info for a tile cache entry */
126 void fgTileCacheEntryInfo( int index, GLint *display_list,
127 struct fgCartesianPoint *local_ref ) {
128 *display_list = tile_cache[index].display_list;
129 /* fgPrintf(FG_TERRAIN, FG_DEBUG, "Display list = %d\n", *display_list); */
131 local_ref->x = tile_cache[index].local_ref.x;
132 local_ref->y = tile_cache[index].local_ref.y;
133 local_ref->z = tile_cache[index].local_ref.z;
137 /* Return index of next available slot in tile cache */
138 int fgTileCacheNextAvail( void ) {
141 float dx, dy, dz, max, med, min, tmp;
142 float dist, max_dist;
150 for ( i = 0; i < FG_TILE_CACHE_SIZE; i++ ) {
151 if ( tile_cache[i].used == 0 ) {
154 /* calculate approximate distance from view point */
155 fgPrintf( FG_TERRAIN, FG_DEBUG,
156 "DIST Abs view pos = %.4f, %.4f, %.4f\n",
157 v->abs_view_pos.x, v->abs_view_pos.y, v->abs_view_pos.z );
158 fgPrintf( FG_TERRAIN, FG_DEBUG,
159 " ref point = %.4f, %.4f, %.4f\n",
160 tile_cache[i].local_ref.x, tile_cache[i].local_ref.y,
161 tile_cache[i].local_ref.z);
163 dx = fabs(tile_cache[i].local_ref.x - v->abs_view_pos.x);
164 dy = fabs(tile_cache[i].local_ref.y - v->abs_view_pos.y);
165 dz = fabs(tile_cache[i].local_ref.z - v->abs_view_pos.z);
167 max = dx; med = dy; min = dz;
169 tmp = max; max = med; med = tmp;
172 tmp = max; max = min; min = tmp;
174 dist = max + (med + min) / 4;
176 fgPrintf( FG_TERRAIN, FG_DEBUG, " distance = %.2f\n", dist);
178 if ( dist > max_dist ) {
185 /* If we made it this far, then there were no open cache entries.
186 * We will instead free the furthest cache entry and return it's
189 fgTileCacheEntryFree( max_index );
195 /* Revision 1.6 1998/01/31 00:43:26 curt
196 /* Added MetroWorks patches from Carmen Volpe.
198 * Revision 1.5 1998/01/29 00:51:39 curt
199 * First pass at tile cache, dynamic tile loading and tile unloading now works.
201 * Revision 1.4 1998/01/27 03:26:43 curt
202 * Playing with new fgPrintf command.
204 * Revision 1.3 1998/01/27 00:48:03 curt
205 * Incorporated Paul Bleisch's <bleisch@chromatic.com> new debug message
206 * system and commandline/config file processing code.
208 * Revision 1.2 1998/01/26 15:55:24 curt
209 * Progressing on building dynamic scenery system.
211 * Revision 1.1 1998/01/24 00:03:29 curt