-/**************************************************************************
- * bucketutils.c -- support routines to handle fgBUCKET operations
- *
- * Written by Curtis Olson, started January 1998.
- *
- * 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)
- **************************************************************************/
-
-
-#include <math.h>
-#include <stdio.h>
-
-#include <Include/fg_constants.h>
-#include <Scenery/bucketutils.h>
-
-
-/* Generate the unique scenery tile index containing the specified
- lon/lat parameters.
-
- The index is constructed as follows:
-
- 9 bits - to represent 360 degrees of longitude (-180 to 179)
- 8 bits - to represent 180 degrees of latitude (-90 to 89)
-
- Each 1 degree by 1 degree tile is further broken down into an 8x8
- grid. So we also need:
-
- 3 bits - to represent x (0 to 7)
- 3 bits - to represent y (0 to 7) */
-long int fgBucketGenIndex(struct fgBUCKET *p) {
- long index = 0;
-
- index = ((p->lon + 180) << 14) + ((p->lat + 90) << 6) + (p->y << 3) + p->x;
- /* printf(" generated index = %ld\n", index); */
-
- return(index);
-}
-
-
-/* Parse a unique scenery tile index and find the lon, lat, x, and y */
-void fgBucketParseIndex(long int index, struct fgBUCKET *p) {
- p->lon = index >> 14;
- index -= p->lon << 14;
- p->lon -= 180;
-
- p->lat = index >> 6;
- index -= p->lat << 6;
- p->lat -= 90;
-
- p->y = index >> 3;
- index -= p->y << 3;
-
- p->x = index;
-}
-
-
-/* Build a path name from an tile index */
-void fgBucketGenBasePath(struct fgBUCKET *p, char *path) {
- long int index;
- int top_lon, top_lat, main_lon, main_lat;
- char hem, pole;
-
- index = fgBucketGenIndex(p);
-
- path[0] = '\0';
-
- top_lon = p->lon / 10;
- main_lon = p->lon;
- if ( (p->lon < 0) && (top_lon * 10 != p->lon) ) {
- top_lon -= 1;
- }
- top_lon *= 10;
- if ( top_lon >= 0 ) {
- hem = 'e';
- } else {
- hem = 'w';
- top_lon *= -1;
- }
- if ( main_lon < 0 ) {
- main_lon *= -1;
- }
-
- top_lat = p->lat / 10;
- main_lat = p->lat;
- if ( (p->lat < 0) && (top_lat * 10 != p->lat) ) {
- top_lat -= 1;
- }
- top_lat *= 10;
- if ( top_lat >= 0 ) {
- pole = 'n';
- } else {
- pole = 's';
- top_lat *= -1;
- }
- if ( main_lat < 0 ) {
- main_lat *= -1;
- }
-
- sprintf(path, "%c%03d%c%03d/%c%03d%c%03d",
- hem, top_lon, pole, top_lat,
- hem, main_lon, pole, main_lat);
-}
-
-
-/* offset an bucket struct by the specified amounts in the X & Y direction */
-void fgBucketOffset(struct fgBUCKET *in, struct fgBUCKET *out, int x, int y) {
- int diff, temp;
- int dist_lat;
-
- out->lon = in->lon;
- out->lat = in->lat;
- out->x = in->x;
- out->y = in->y;
-
- /* do X direction */
- diff = out->x + x;
- /* printf(" reducing x (%d)\n", diff); */
- if ( diff >= 0 ) {
- temp = diff / 8;
- } else if ( diff < -7 ) {
- temp = (diff + 1) / 8 - 1;
- } else {
- temp = diff / 8 - 1;
- }
- out->x = ((diff % 8) + 8) % 8;
- out->lon = ( (out->lon + 180 + 360 + temp) % 360 ) - 180;
-
- /* do Y direction */
- diff = out->y + y;
- /* printf(" reducing x (%d)\n", diff); */
- if ( diff >= 0 ) {
- temp = diff / 8;
- } else if ( diff < -7 ) {
- temp = (diff + 1) / 8 - 1;
- } else {
- temp = diff / 8 - 1;
- }
- out->y = ((diff % 8) + 8) % 8;
- out->lat = out->lat + temp;
-
- if ( out->lat >= 90 ) {
- dist_lat = out->lat - 90;
- /* printf(" +lat = %d +y = %d\n", dist_lat, out->y); */
-
- out->lat = 90 - (dist_lat + 1);
- out->lon = ( (out->lon + 180 + 180) % 360 ) - 180;
- out->y = 7 - out->y;
- }
-
- if ( out->lat < -90 ) {
- dist_lat = -90 - out->lat;
- /* printf(" +lat = %d +y = %d\n", dist_lat, out->y); */
-
- out->lat = -90 + (dist_lat - 1);
- out->lon = ( (out->lon + 180 + 180) % 360 ) - 180;
- out->y = 7 - out->y;
- }
-}
-
-
-/* Given a lat/lon, find the "bucket" or tile that it falls within */
-void fgBucketFind(double lon, double lat, struct fgBUCKET *p) {
- double diff;
-
- diff = lon - (double)(int)lon;
- /* printf("diff = %.2f\n", diff); */
- if ( (lon >= 0) || (fabs(diff) < FG_EPSILON) ) {
- p->lon = (int)lon;
- } else {
- p->lon = (int)lon - 1;
- }
- /* printf(" p->lon = %d\n", p->lon); */
-
- diff = lat - (double)(int)lat;
- /* printf("diff = %.2f\n", diff); */
- if ( (lat >= 0) || (fabs(diff) < FG_EPSILON) ) {
- p->lat = (int)lat;
- } else {
- p->lat = (int)lat - 1;
- }
- /* printf(" p->lat = %d\n", p->lat); */
-
- p->x = (int)((lon - p->lon) * 8);
- p->y = (int)((lat - p->lat) * 8);
- /* printf( "Bucket = lon,lat = %d,%d x,y index = %d,%d\n",
- p->lon, p->lat, p->x, p->y); */
-}
-
-
-/* Given a lat/lon, fill in the local tile index array */
-void fgBucketGenIdxArray(struct fgBUCKET *p1, struct fgBUCKET *tiles,
- int width, int height) {
- struct fgBUCKET *p2;
- int dw, dh, i, j;
-
- dh = height / 2;
- dw = width / 2;
- for ( j = 0; j < height; j++ ) {
- for ( i = 0; i < width; i++ ) {
- fgBucketOffset(p1, &tiles[(j*width)+i], i - dw, j - dh);
- p2 = &tiles[(j*width)+i];
- /* printf( " bucket = %d %d %d %d index = %ld\n",
- p2->lon, p2->lat, p2->x, p2->y,
- fgBucketGenIndex(&tiles[(j*width)+i])); */
- }
- }
-}
-
-
-/* sample main for testing
-int main() {
- struct fgBUCKET p1;
- long int tile[49];
- char path[256];
- double lon, lat;
- int i, j;
-
- p1.lon = 180;
- p1.lat = 90;
- p1.x = 7;
- p1.y = 7;
-
- printf("Max index = %ld\n", gen_index(&p1));
-
- lon = -50.0;
- lat = -50.0;
- find_bucket(lon, lat, &p1);
- gen_idx_array(&p1, tile, 7, 7);
- for ( j = 0; j < 7; j++ ) {
- for ( i = 0; i < 7; i++ ) {
- gen_path(tile[(j*7)+i], path);
- printf(" path = %s\n", path);
- }
- }
-
- lon = 50.0;
- lat = 50.0;
- find_bucket(lon, lat, &p1);
- gen_idx_array(&p1, tile, 7, 7);
- for ( j = 0; j < 7; j++ ) {
- for ( i = 0; i < 7; i++ ) {
- gen_path(tile[(j*7)+i], path);
- printf(" path = %s\n", path);
- }
- }
-
- return(1);
-} */
-
-
-/* $Log$
-/* Revision 1.6 1998/02/09 15:07:51 curt
-/* Minor tweaks.
-/*
- * Revision 1.5 1998/01/29 00:51:38 curt
- * First pass at tile cache, dynamic tile loading and tile unloading now works.
- *
- * Revision 1.4 1998/01/27 03:26:41 curt
- * Playing with new fgPrintf command.
- *
- * Revision 1.3 1998/01/27 00:48:01 curt
- * Incorporated Paul Bleisch's <bleisch@chromatic.com> new debug message
- * system and commandline/config file processing code.
- *
- * Revision 1.2 1998/01/24 00:03:28 curt
- * Initial revision.
- *
- * Revision 1.1 1998/01/23 20:06:51 curt
- * tileutils.* renamed to bucketutils.*
- *
- * Revision 1.6 1998/01/19 19:27:18 curt
- * Merged in make system changes from Bob Kuehne <rpk@sgi.com>
- * This should simplify things tremendously.
- *
- * Revision 1.5 1998/01/14 02:19:04 curt
- * Makde offset_bucket visible to outside.
- *
- * Revision 1.4 1998/01/13 00:23:12 curt
- * Initial changes to support loading and management of scenery tiles. Note,
- * there's still a fair amount of work left to be done.
- *
- * Revision 1.3 1998/01/10 00:01:47 curt
- * Misc api changes and tweaks.
- *
- * Revision 1.2 1998/01/08 02:22:28 curt
- * Continue working on basic features.
- *
- * Revision 1.1 1998/01/07 23:50:52 curt
- * "area" renamed to "tile"
- *
- * Revision 1.1 1998/01/07 23:23:40 curt
- * Initial revision.
- *
- * */
-
-