1 // tilemgr.cxx -- routines to handle dynamic management of scenery tiles
3 // Written by Curtis Olson, started January 1998.
5 // Copyright (C) 1997 Curtis L. Olson - curt@infoplane.com
7 // This program is free software; you can redistribute it and/or
8 // modify it under the terms of the GNU General Public License as
9 // published by the Free Software Foundation; either version 2 of the
10 // License, or (at your option) any later version.
12 // This program is distributed in the hope that it will be useful, but
13 // WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 // General Public License for more details.
17 // You should have received a copy of the GNU General Public License
18 // along with this program; if not, write to the Free Software
19 // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 // (Log is kept at end of this file)
36 #include <Aircraft/aircraft.h>
38 #include <Bucket/bucketutils.h>
39 #include <Debug/fg_debug.h>
40 #include <Include/fg_constants.h>
41 #include <Include/fg_types.h>
42 #include <Main/options.hxx>
43 #include <Main/views.hxx>
44 #include <Math/fg_geodesy.h>
45 #include <Math/mat3.h>
46 #include <Math/polar3d.hxx>
47 #include <Math/vector.hxx>
48 #include <Objects/material.hxx>
49 #include <Objects/obj.hxx>
50 #include <Weather/weather.h>
52 #include "scenery.hxx"
53 #include "tilecache.hxx"
56 // to test clipping speedup in fgTileMgrRender()
57 #if defined ( USE_FAST_FOV_CLIP )
58 // #define TEST_FOV_CLIP
63 #define FG_LOCAL_X_Y 81 // max(o->tile_diameter) ** 2
65 #define FG_SQUARE( X ) ( (X) * (X) )
68 # define FG_MEM_COPY(to,from,n) memcpy(to, from, n)
70 # define FG_MEM_COPY(to,from,n) bcopy(from, to, n)
73 // closest (potentially viewable) tiles, centered on current tile.
74 // This is an array of pointers to cache indexes.
75 int tiles[FG_LOCAL_X_Y];
78 // Initialize the Tile Manager subsystem
79 int fgTileMgrInit( void ) {
80 fgPrintf( FG_TERRAIN, FG_INFO, "Initializing Tile Manager subsystem.\n");
82 // load default material library
83 material_mgr.load_lib();
90 void fgTileMgrLoadTile( fgBUCKET *p, int *index) {
93 c = &global_tile_cache;
95 fgPrintf( FG_TERRAIN, FG_DEBUG, "Updating for bucket %d %d %d %d\n",
96 p->lon, p->lat, p->x, p->y);
98 // if not in cache, load tile into the next available slot
99 if ( (*index = c->exists(p)) < 0 ) {
100 *index = c->next_avail();
101 c->fill_in(*index, p);
104 fgPrintf( FG_TERRAIN, FG_DEBUG, "Selected cache index of %d\n", *index);
108 // given the current lon/lat, fill in the array of local chunks. If
109 // the chunk isn't already in the cache, then read it from disk.
110 int fgTileMgrUpdate( void ) {
114 static fgBUCKET p_last = {-1000, 0, 0, 0};
118 c = &global_tile_cache;
119 f = current_aircraft.flight;
121 tile_diameter = current_options.get_tile_diameter();
123 fgBucketFind(FG_Longitude * RAD_TO_DEG, FG_Latitude * RAD_TO_DEG, &p1);
124 dw = tile_diameter / 2;
125 dh = tile_diameter / 2;
127 if ( (p1.lon == p_last.lon) && (p1.lat == p_last.lat) &&
128 (p1.x == p_last.x) && (p1.y == p_last.y) ) {
129 // same bucket as last time
130 fgPrintf( FG_TERRAIN, FG_DEBUG, "Same bucket as last time\n");
131 } else if ( p_last.lon == -1000 ) {
132 // First time through, initialize the system and load all
135 fgPrintf( FG_TERRAIN, FG_INFO, " First time through ... ");
136 fgPrintf( FG_TERRAIN, FG_INFO, " Updating Tile list for %d,%d %d,%d\n",
137 p1.lon, p1.lat, p1.x, p1.y);
138 fgPrintf( FG_TERRAIN, FG_INFO, " Loading %d tiles\n",
139 tile_diameter * tile_diameter);
141 // wipe/initialize tile cache
144 // build the local area list and update cache
145 for ( j = 0; j < tile_diameter; j++ ) {
146 for ( i = 0; i < tile_diameter; i++ ) {
147 fgBucketOffset(&p1, &p2, i - dw, j - dh);
148 fgTileMgrLoadTile(&p2, &tiles[(j*tile_diameter) + i]);
152 // We've moved to a new bucket, we need to scroll our
153 // structures, and load in the new tiles
155 // CURRENTLY THIS ASSUMES WE CAN ONLY MOVE TO ADJACENT TILES.
156 // AT ULTRA HIGH SPEEDS THIS ASSUMPTION MAY NOT BE VALID IF
157 // THE AIRCRAFT CAN SKIP A TILE IN A SINGLE ITERATION.
159 fgPrintf( FG_TERRAIN, FG_INFO, "Updating Tile list for %d,%d %d,%d\n",
160 p1.lon, p1.lat, p1.x, p1.y);
162 if ( (p1.lon > p_last.lon) ||
163 ( (p1.lon == p_last.lon) && (p1.x > p_last.x) ) ) {
164 fgPrintf( FG_TERRAIN, FG_INFO, " Loading %d tiles\n",
166 for ( j = 0; j < tile_diameter; j++ ) {
168 for ( i = 0; i < tile_diameter - 1; i++ ) {
169 tiles[(j*tile_diameter) + i] =
170 tiles[(j*tile_diameter) + i + 1];
172 // load in new column
173 fgBucketOffset(&p_last, &p2, dw + 1, j - dh);
174 fgTileMgrLoadTile(&p2, &tiles[(j*tile_diameter) +
177 } else if ( (p1.lon < p_last.lon) ||
178 ( (p1.lon == p_last.lon) && (p1.x < p_last.x) ) ) {
179 fgPrintf( FG_TERRAIN, FG_INFO, " Loading %d tiles\n",
181 for ( j = 0; j < tile_diameter; j++ ) {
183 for ( i = tile_diameter - 1; i > 0; i-- ) {
184 tiles[(j*tile_diameter) + i] =
185 tiles[(j*tile_diameter) + i - 1];
187 // load in new column
188 fgBucketOffset(&p_last, &p2, -dw - 1, j - dh);
189 fgTileMgrLoadTile(&p2, &tiles[(j*tile_diameter) + 0]);
193 if ( (p1.lat > p_last.lat) ||
194 ( (p1.lat == p_last.lat) && (p1.y > p_last.y) ) ) {
195 fgPrintf( FG_TERRAIN, FG_INFO, " Loading %d tiles\n",
197 for ( i = 0; i < tile_diameter; i++ ) {
199 for ( j = 0; j < tile_diameter - 1; j++ ) {
200 tiles[(j * tile_diameter) + i] =
201 tiles[((j+1) * tile_diameter) + i];
203 // load in new column
204 fgBucketOffset(&p_last, &p2, i - dw, dh + 1);
205 fgTileMgrLoadTile(&p2, &tiles[((tile_diameter-1) *
206 tile_diameter) + i]);
208 } else if ( (p1.lat < p_last.lat) ||
209 ( (p1.lat == p_last.lat) && (p1.y < p_last.y) ) ) {
210 fgPrintf( FG_TERRAIN, FG_INFO, " Loading %d tiles\n",
212 for ( i = 0; i < tile_diameter; i++ ) {
214 for ( j = tile_diameter - 1; j > 0; j-- ) {
215 tiles[(j * tile_diameter) + i] =
216 tiles[((j-1) * tile_diameter) + i];
218 // load in new column
219 fgBucketOffset(&p_last, &p2, i - dw, -dh - 1);
220 fgTileMgrLoadTile(&p2, &tiles[0 + i]);
232 // Calculate shortest distance from point to line
233 static double point_line_dist_squared( fgPoint3d *tc, fgPoint3d *vp,
239 p[0] = tc->x; p[1] = tc->y; p[2] = tc->z;
240 p0[0] = vp->x; p0[1] = vp->y; p0[2] = vp->z;
242 dist = fgPointLineSquared(p, p0, d);
244 // printf("dist = %.2f\n", dist);
250 // Calculate if point/radius is inside view frustum
251 static int viewable( fgPoint3d *cp, double radius ) {
252 int viewable = 1; // start by assuming it's viewable
255 /********************************/
256 #if defined( USE_FAST_FOV_CLIP ) // views.hxx
257 /********************************/
267 mat = (double *)(current_view.WORLD_TO_EYE);
269 eye[2] = x*mat[2] + y*mat[6] + z*mat[10] + mat[14];
271 // Check near and far clip plane
272 if( ( eye[2] > radius ) ||
273 ( eye[2] + radius + current_weather.visibility < 0) )
278 eye[0] = (x*mat[0] + y*mat[4] + z*mat[8] + mat[12]) * current_view.slope_x;
280 // check right and left clip plane (from eye perspective)
281 x1 = radius * current_view.fov_x_clip;
282 if( (eye[2] > -(eye[0]+x1)) || (eye[2] > (eye[0]-x1)) )
287 eye[1] = (x*mat[1] + y*mat[5] + z*mat[9] + mat[13]) * current_view.slope_y;
289 // check bottom and top clip plane (from eye perspective)
290 y1 = radius * current_view.fov_y_clip;
291 if( (eye[2] > -(eye[1]+y1)) || (eye[2] > (eye[1]-y1)) )
296 /********************************/
297 #else // DO NOT USE_FAST_FOV_CLIP
298 /********************************/
306 MAT3_SET_HVEC(world, cp->x, cp->y, cp->z, 1.0);
307 // MAT3mult_vec(eye, world, v->WORLD_TO_EYE);
308 // printf( "\nworld -> eye = %.2f %.2f %.2f radius = %.2f\n",
309 // eye[0], eye[1], eye[2], radius);
311 // Use lazy evaluation for calculating eye hvec.
313 #define mat v->WORLD_TO_EYE
314 eye[2] = vec[0]*mat[0][2]+vec[1]*mat[1][2]+vec[2]*mat[2][2]+mat[3][2];
316 // Check near clip plane
317 if ( eye[2] > radius ) {
321 // Check far clip plane
322 if ( eye[2] + radius < -current_weather.visibility ) {
326 // check right clip plane (from eye perspective)
327 // y = m * (x - x0) = equation of a line intercepting X axis at x0
328 x1 = v->cos_fov_x * radius;
329 y1 = v->sin_fov_x * radius;
331 eye[0] = vec[0]*mat[0][0]+vec[1]*mat[1][0]+vec[2]*mat[2][0]+mat[3][0];
333 if ( eye[2] > ((slope * (eye[0] - x1)) + y1) ) {
337 // check left clip plane (from eye perspective)
338 if ( eye[2] > -((slope * (eye[0] + x1)) - y1) ) {
342 // check bottom clip plane (from eye perspective)
343 x1 = -(v->cos_fov_y) * radius;
344 y1 = v->sin_fov_y * radius;
346 eye[1] = vec[0]*mat[0][1]+vec[1]*mat[1][1]+vec[2]*mat[2][1]+mat[3][1];
350 if ( eye[2] > ((slope * (eye[1] - x1)) + y1) ) {
354 // check top clip plane (from eye perspective)
355 if ( eye[2] > -((slope * (eye[1] + x1)) - y1) ) {
359 #endif // defined( USE_FAST_FOV_CLIP )
367 // inrange() IS THIS POINT WITHIN POSSIBLE VIEWING RANGE ?
368 // calculate distance from vertical tangent line at
369 // current position to center of object.
370 // this is equivalent to
371 // dist = point_line_dist_squared( &(t->center), &(v->abs_view_pos),
373 // if ( dist < FG_SQUARE(t->bounding_radius) ) {
375 // the compiler should inline this for us
378 inrange( const double radius, const fgPoint3d *center, const fgPoint3d *vp,
385 u[0] = center->x - vp->x;
386 u[1] = center->y - vp->y;
387 u[2] = center->z - vp->z;
389 // calculate the projection, u1, of u along d.
390 // u1 = ( dot_prod(u, d) / dot_prod(d, d) ) * d;
392 MAT3_SCALE_VEC(u1, up,
393 (MAT3_DOT_PRODUCT(u, up) / MAT3_DOT_PRODUCT(up, up)) );
395 // v = u - u1 = vector from closest point on line, p1, to the
396 // original point, p.
397 MAT3_SUB_VEC(v, u, u1);
399 return( FG_SQUARE(radius) >= MAT3_DOT_PRODUCT(v, v));
403 // Determine scenery altitude. Normally this just happens when we
404 // render the scene, but we'd also like to be able to do this
405 // explicitely. lat & lon are in radians. abs_view_pos in meters.
406 // Returns result in meters.
407 double fgTileMgrCurElev( double lon, double lat, fgPoint3d *abs_view_pos ) {
411 fgFRAGMENT *frag_ptr;
413 fgPoint3d earth_center, result;
416 list < fgFRAGMENT > :: iterator current;
417 list < fgFRAGMENT > :: iterator last;
418 double dist, min_dist, lat_geod, alt, sea_level_r;
420 int index, tile_diameter, i;
422 c = &global_tile_cache;
423 // v = ¤t_view;
425 local_up[0] = abs_view_pos->x;
426 local_up[1] = abs_view_pos->y;
427 local_up[2] = abs_view_pos->z;
429 // Find current translation offset
430 fgBucketFind(lon * RAD_TO_DEG, lat * RAD_TO_DEG, &p);
431 index = c->exists(&p);
432 t = c->get_tile(index);
434 scenery.next_center.x = t->center.x;
435 scenery.next_center.y = t->center.y;
436 scenery.next_center.z = t->center.z;
438 earth_center.x = 0.0;
439 earth_center.y = 0.0;
440 earth_center.z = 0.0;
442 fgPrintf( FG_TERRAIN, FG_DEBUG,
443 "Pos = (%.2f, %.2f) Current bucket = %d %d %d %d Index = %ld\n",
444 lon * RAD_TO_DEG, lat * RAD_TO_DEG,
445 p.lon, p.lat, p.x, p.y, fgBucketGenIndex(&p) );
447 // calculate tile offset
448 x = (t->offset.x = t->center.x - scenery.center.x);
449 y = (t->offset.y = t->center.y - scenery.center.y);
450 z = (t->offset.z = t->center.z - scenery.center.z);
452 // calc current terrain elevation calculate distance from
453 // vertical tangent line at current position to center of
456 /* printf("distance squared = %.2f, bounding radius = %.2f\n",
457 point_line_dist_squared(&(t->offset), &(v->view_pos),
458 v->local_up), t->bounding_radius); */
460 dist = point_line_dist_squared( &(t->center), abs_view_pos,
462 if ( dist < FG_SQUARE(t->bounding_radius) ) {
464 // traverse fragment list for tile
465 current = t->fragment_list.begin();
466 last = t->fragment_list.end();
468 for ( ; current != last; ++current ) {
469 frag_ptr = &(*current);
470 /* printf("distance squared = %.2f, bounding radius = %.2f\n",
471 point_line_dist_squared( &(frag_ptr->center),
472 &abs_view_pos), local_up),
473 frag_ptr->bounding_radius); */
475 dist = point_line_dist_squared( &(frag_ptr->center),
476 abs_view_pos, local_up);
477 if ( dist <= FG_SQUARE(frag_ptr->bounding_radius) ) {
478 if ( frag_ptr->intersect( abs_view_pos,
479 &earth_center, 0, &result ) ) {
480 // compute geocentric coordinates of tile center
481 pp = fgCartToPolar3d(result);
482 // convert to geodetic coordinates
483 fgGeocToGeod(pp.lat, pp.radius, &lat_geod,
485 // printf("alt = %.2f\n", alt);
486 // exit since we found an intersection
493 printf("no terrain intersection found\n");
498 // NEW for legibility
500 // update this tile's geometry for current view
501 // The Compiler should inline this
503 update_tile_geometry( fgTILE *t, GLdouble *MODEL_VIEW)
508 // calculate tile offset
509 x = (t->offset.x = t->center.x - scenery.center.x);
510 y = (t->offset.y = t->center.y - scenery.center.y);
511 z = (t->offset.z = t->center.z - scenery.center.z);
515 // Calculate the model_view transformation matrix for this tile
516 FG_MEM_COPY( m, MODEL_VIEW, 16*sizeof(GLdouble) );
518 // This is equivalent to doing a glTranslatef(x, y, z);
519 m[12] += (m[0]*x + m[4]*y + m[8] *z);
520 m[13] += (m[1]*x + m[5]*y + m[9] *z);
521 m[14] += (m[2]*x + m[6]*y + m[10]*z);
522 // m[15] += (m[3]*x + m[7]*y + m[11]*z);
523 // m[3] m7[] m[11] are 0.0 see LookAt() in views.cxx
524 // so m[15] is unchanged
528 // Render the local tiles
529 void fgTileMgrRender( void ) {
532 fgTILE *t, *last_tile_ptr;
535 fgPoint3d frag_offset, pp;
536 fgPoint3d earth_center, result;
537 fgFRAGMENT *frag_ptr;
540 double dist, min_dist, lat_geod, alt, sea_level_r;
542 list < fgFRAGMENT > :: iterator current;
543 list < fgFRAGMENT > :: iterator last;
545 int tile_diameter, textures;
551 c = &global_tile_cache;
552 f = current_aircraft.flight;
555 tile_diameter = current_options.get_tile_diameter();
556 textures = current_options.get_textures();
558 // Find current translation offset
559 fgBucketFind(FG_Longitude * RAD_TO_DEG, FG_Latitude * RAD_TO_DEG, &p);
560 index = c->exists(&p);
561 t = c->get_tile(index);
563 scenery.next_center.x = t->center.x;
564 scenery.next_center.y = t->center.y;
565 scenery.next_center.z = t->center.z;
567 earth_center.x = 0.0;
568 earth_center.y = 0.0;
569 earth_center.z = 0.0;
571 fgPrintf( FG_TERRAIN, FG_DEBUG,
572 "Pos = (%.2f, %.2f) Current bucket = %d %d %d %d Index = %ld\n",
573 FG_Longitude * RAD_TO_DEG, FG_Latitude * RAD_TO_DEG,
574 p.lon, p.lat, p.x, p.y, fgBucketGenIndex(&p) );
576 // initialize the transient per-material fragment lists
577 material_mgr.init_transient_material_lists();
580 scenery.cur_elev = fgTileMgrCurElev( FG_Longitude, FG_Latitude,
581 &(v->abs_view_pos) );
584 // traverse the potentially viewable tile list
585 for ( i = 0; i < (tile_diameter * tile_diameter); i++ ) {
587 // fgPrintf( FG_TERRAIN, FG_DEBUG, "Index = %d\n", index);
588 t = c->get_tile(index);
590 // calculate tile offset
591 x = (t->offset.x = t->center.x - scenery.center.x);
592 y = (t->offset.y = t->center.y - scenery.center.y);
593 z = (t->offset.z = t->center.z - scenery.center.z);
596 for ( j = 0; j < 16; j++ ) {
597 m[j] = v->MODEL_VIEW[j];
600 // Calculate the model_view transformation matrix for this tile
601 // This is equivalent to doing a glTranslatef(x, y, z);
602 m[12] = m[0] * x + m[4] * y + m[8] * z + m[12];
603 m[13] = m[1] * x + m[5] * y + m[9] * z + m[13];
604 m[14] = m[2] * x + m[6] * y + m[10] * z + m[14];
605 m[15] = m[3] * x + m[7] * y + m[11] * z + m[15];
607 #if defined( TEST_FOV_CLIP )
608 if( viewable(&(t->offset), t->bounding_radius) !=
609 viewable2(&(t->offset), t->bounding_radius) )
611 printf("FOV PROBLEM\n");
614 #endif // defined( TEST_FOV_CLIP )
616 // Course (tile based) culling
617 if ( viewable(&(t->offset), t->bounding_radius) ) {
618 // at least a portion of this tile could be viewable
621 // xglTranslatef(t->offset.x, t->offset.y, t->offset.z);
623 // traverse fragment list for tile
624 current = t->fragment_list.begin();
625 last = t->fragment_list.end();
627 for ( ; current != last; ++current ) {
628 frag_ptr = &(*current);
630 if ( frag_ptr->display_list >= 0 ) {
631 // Fine (fragment based) culling
632 frag_offset.x = frag_ptr->center.x - scenery.center.x;
633 frag_offset.y = frag_ptr->center.y - scenery.center.y;
634 frag_offset.z = frag_ptr->center.z - scenery.center.z;
636 #if defined( TEST_FOV_CLIP )
637 radius = frag_ptr->bounding_radius*2;
638 if ( viewable(&frag_offset, radius) !=
639 viewable2(&frag_offset, radius) ) {
640 printf("FOV PROBLEM\n");
643 #endif // defined( TEST_FOV_CLIP )
645 if ( viewable(&frag_offset, frag_ptr->bounding_radius*2) ) {
646 // add to transient per-material property fragment list
647 // frag_ptr->tile_offset.x = t->offset.x;
648 // frag_ptr->tile_offset.y = t->offset.y;
649 // frag_ptr->tile_offset.z = t->offset.z;
651 mtl_ptr = frag_ptr->material_ptr;
652 // printf(" lookup = %s\n", mtl_ptr->texture_name);
653 if ( ! mtl_ptr->append_sort_list( frag_ptr ) ) {
654 fgPrintf( FG_TERRAIN, FG_ALERT,
655 "Overran material sorting array\n" );
658 // xglCallList(frag_ptr->display_list);
661 // printf("Culled a fragment %.2f %.2f %.2f %.2f\n",
662 // frag_ptr->center.x, frag_ptr->center.y,
663 // frag_ptr->center.z, frag_ptr->bounding_radius);
671 culled += t->fragment_list.size();
675 if ( (drawn + culled) > 0 ) {
676 v->vfc_ratio = (double)culled / (double)(drawn + culled);
680 // printf("drawn = %d culled = %d saved = %.2f\n", drawn, culled,
684 // traverse the transient per-material fragment lists and render
685 // out all fragments for each material property.
687 material_mgr.render_fragments();
693 // Revision 1.36 1998/09/14 12:45:26 curt
696 // Revision 1.35 1998/09/10 19:07:16 curt
697 // /Simulator/Objects/fragment.hxx
698 // Nested fgFACE inside fgFRAGMENT since its not used anywhere else.
700 // ./Simulator/Objects/material.cxx
701 // ./Simulator/Objects/material.hxx
702 // Made fgMATERIAL and fgMATERIAL_MGR bona fide classes with private
703 // data members - that should keep the rabble happy :)
705 // ./Simulator/Scenery/tilemgr.cxx
706 // In viewable() delay evaluation of eye[0] and eye[1] in until they're
708 // Change to fgTileMgrRender() to call fgMATERIAL_MGR::render_fragments()
711 // ./Include/fg_stl_config.h
712 // ./Include/auto_ptr.hxx
713 // Added support for g++ 2.7.
714 // Further changes to other files are forthcoming.
716 // Brief summary of changes required for g++ 2.7.
717 // operator->() not supported by iterators: use (*i).x instead of i->x
718 // default template arguments not supported,
719 // <functional> doesn't have mem_fun_ref() needed by callbacks.
720 // some std include files have different names.
721 // template member functions not supported.
723 // Revision 1.34 1998/09/09 20:58:09 curt
724 // Tweaks to loop constructs with STL usage.
726 // Revision 1.33 1998/09/08 15:05:10 curt
727 // Optimization by Norman Vine.
729 // Revision 1.32 1998/08/25 16:52:44 curt
730 // material.cxx material.hxx obj.cxx obj.hxx texload.c texload.h moved to
733 // Revision 1.31 1998/08/24 20:11:40 curt
736 // Revision 1.30 1998/08/22 14:49:59 curt
737 // Attempting to iron out seg faults and crashes.
738 // Did some shuffling to fix a initialization order problem between view
739 // position, scenery elevation.
741 // Revision 1.29 1998/08/20 15:12:06 curt
742 // Used a forward declaration of classes fgTILE and fgMATERIAL to eliminate
743 // the need for "void" pointers and casts.
744 // Quick hack to count the number of scenery polygons that are being drawn.
746 // Revision 1.28 1998/08/12 21:13:06 curt
747 // material.cxx: don't load textures if they are disabled
748 // obj.cxx: optimizations from Norman Vine
749 // tile.cxx: minor tweaks
750 // tile.hxx: addition of num_faces
751 // tilemgr.cxx: minor tweaks
753 // Revision 1.27 1998/07/24 21:42:09 curt
754 // material.cxx: whups, double method declaration with no definition.
755 // obj.cxx: tweaks to avoid errors in SGI's CC.
756 // tile.cxx: optimizations by Norman Vine.
757 // tilemgr.cxx: optimizations by Norman Vine.
759 // Revision 1.26 1998/07/20 12:51:26 curt
760 // Added far clip plane to fragment clipping calculations and tie this to
761 // weather->visibility. This way you can increase framerates by increasing
762 // for and lowering visibility.
764 // Revision 1.25 1998/07/13 21:02:01 curt
765 // Wrote access functions for current fgOPTIONS.
767 // Revision 1.24 1998/07/12 03:18:29 curt
768 // Added ground collision detection. This involved:
769 // - saving the entire vertex list for each tile with the tile records.
770 // - saving the face list for each fragment with the fragment records.
771 // - code to intersect the current vertical line with the proper face in
772 // an efficient manner as possible.
773 // Fixed a bug where the tiles weren't being shifted to "near" (0,0,0)
775 // Revision 1.23 1998/07/08 14:47:23 curt
776 // Fix GL_MODULATE vs. GL_DECAL problem introduced by splash screen.
777 // polare3d.h renamed to polar3d.hxx
778 // fg{Cartesian,Polar}Point3d consolodated.
779 // Added some initial support for calculating local current ground elevation.
781 // Revision 1.22 1998/07/04 00:54:31 curt
782 // Added automatic mipmap generation.
784 // When rendering fragments, use saved model view matrix from associated tile
785 // rather than recalculating it with push() translate() pop().
787 // Revision 1.21 1998/06/27 16:54:59 curt
788 // Check for GL_VERSION_1_1 or GL_EXT_texture_object to decide whether to use
789 // "EXT" versions of texture management routines.
791 // Revision 1.20 1998/06/17 21:36:42 curt
792 // Load and manage multiple textures defined in the Materials library.
793 // Boost max material fagments for each material property to 800.
794 // Multiple texture support when rendering.
796 // Revision 1.19 1998/06/08 17:57:54 curt
797 // Working first pass at material proporty sorting.
799 // Revision 1.18 1998/06/06 01:09:32 curt
800 // I goofed on the log message in the last commit ... now fixed.
802 // Revision 1.17 1998/06/06 01:07:18 curt
803 // Increased per material fragment list size from 100 to 400.
804 // Now correctly draw viewable fragments in per material order.
806 // Revision 1.16 1998/06/05 22:39:55 curt
807 // Working on sorting by, and rendering by material properties.
809 // Revision 1.15 1998/06/03 00:47:51 curt
810 // No .h for STL includes.
811 // Minor view culling optimizations.
813 // Revision 1.14 1998/06/01 17:56:20 curt
814 // Incremental additions to material.cxx (not fully functional)
815 // Tweaked vfc_ratio math to avoid divide by zero.
817 // Revision 1.13 1998/05/24 02:49:10 curt
818 // Implimented fragment level view frustum culling.
820 // Revision 1.12 1998/05/23 14:09:23 curt
821 // Added tile.cxx and tile.hxx.
822 // Working on rewriting the tile management system so a tile is just a list
823 // fragments, and the fragment record contains the display list for that fragment.
825 // Revision 1.11 1998/05/20 20:53:55 curt
826 // Moved global ref point and radius (bounding sphere info, and offset) to
827 // data file rather than calculating it on the fly.
828 // Fixed polygon winding problem in scenery generation stage rather than
829 // compensating for it on the fly.
830 // Made a fgTILECACHE class.
832 // Revision 1.10 1998/05/17 16:59:34 curt
833 // Frist pass at view frustum culling now operational.
835 // Revision 1.9 1998/05/16 13:09:58 curt
836 // Beginning to add support for view frustum culling.
837 // Added some temporary code to calculate bouding radius, until the
838 // scenery generation tools and scenery can be updated.
840 // Revision 1.8 1998/05/07 23:15:21 curt
841 // Fixed a glTexImage2D() usage bug where width and height were mis-swapped.
842 // Added support for --tile-radius=n option.
844 // Revision 1.7 1998/05/06 03:16:42 curt
845 // Added an option to control square tile radius.
847 // Revision 1.6 1998/05/02 01:52:18 curt
848 // Playing around with texture coordinates.
850 // Revision 1.5 1998/04/30 12:35:32 curt
851 // Added a command line rendering option specify smooth/flat shading.
853 // Revision 1.4 1998/04/27 03:30:14 curt
854 // Minor transformation adjustments to try to keep scenery tiles closer to
855 // (0, 0, 0) GLfloats run out of precision at the distances we need to model
856 // the earth, but we can do a bunch of pre-transformations using double math
857 // and then cast to GLfloat once everything is close in where we have less
858 // precision problems.
860 // Revision 1.3 1998/04/25 22:06:32 curt
861 // Edited cvs log messages in source files ... bad bad bad!
863 // Revision 1.2 1998/04/24 00:51:09 curt
864 // Wrapped "#include <config.h>" in "#ifdef HAVE_CONFIG_H"
865 // Tweaked the scenery file extentions to be "file.obj" (uncompressed)
866 // or "file.obz" (compressed.)
868 // Revision 1.1 1998/04/22 13:22:48 curt
869 // C++ - ifing the code a bit.
871 // Revision 1.25 1998/04/18 04:14:07 curt
872 // Moved fg_debug.c to it's own library.
874 // Revision 1.24 1998/04/14 02:23:18 curt
875 // Code reorganizations. Added a Lib/ directory for more general libraries.
877 // Revision 1.23 1998/04/08 23:30:08 curt
878 // Adopted Gnu automake/autoconf system.
880 // Revision 1.22 1998/04/03 22:11:38 curt
881 // Converting to Gnu autoconf system.
883 // Revision 1.21 1998/03/23 21:23:05 curt
884 // Debugging output tweaks.
886 // Revision 1.20 1998/03/14 00:30:51 curt
887 // Beginning initial terrain texturing experiments.
889 // Revision 1.19 1998/02/20 00:16:25 curt
890 // Thursday's tweaks.
892 // Revision 1.18 1998/02/19 13:05:54 curt
893 // Incorporated some HUD tweaks from Michelle America.
894 // Tweaked the sky's sunset/rise colors.
895 // Other misc. tweaks.
897 // Revision 1.17 1998/02/16 13:39:46 curt
898 // Miscellaneous weekend tweaks. Fixed? a cache problem that caused whole
899 // tiles to occasionally be missing.
901 // Revision 1.16 1998/02/12 21:59:53 curt
902 // Incorporated code changes contributed by Charlie Hotchkiss
903 // <chotchkiss@namg.us.anritsu.com>
905 // Revision 1.14 1998/02/09 21:30:19 curt
906 // Fixed a nagging problem with terrain tiles not "quite" matching up perfectly.
908 // Revision 1.13 1998/02/07 15:29:46 curt
909 // Incorporated HUD changes and struct/typedef changes from Charlie Hotchkiss
910 // <chotchkiss@namg.us.anritsu.com>
912 // Revision 1.12 1998/02/01 03:39:55 curt
915 // Revision 1.11 1998/01/31 00:43:27 curt
916 // Added MetroWorks patches from Carmen Volpe.
918 // Revision 1.10 1998/01/29 00:51:40 curt
919 // First pass at tile cache, dynamic tile loading and tile unloading now works.
921 // Revision 1.9 1998/01/27 03:26:44 curt
922 // Playing with new fgPrintf command.
924 // Revision 1.8 1998/01/27 00:48:04 curt
925 // Incorporated Paul Bleisch's <pbleisch@acm.org> new debug message
926 // system and commandline/config file processing code.
928 // Revision 1.7 1998/01/26 15:55:25 curt
929 // Progressing on building dynamic scenery system.
931 // Revision 1.6 1998/01/24 00:03:30 curt
934 // Revision 1.5 1998/01/19 19:27:18 curt
935 // Merged in make system changes from Bob Kuehne <rpk@sgi.com>
936 // This should simplify things tremendously.
938 // Revision 1.4 1998/01/19 18:40:38 curt
939 // Tons of little changes to clean up the code and to remove fatal errors
940 // when building with the c++ compiler.
942 // Revision 1.3 1998/01/13 00:23:11 curt
943 // Initial changes to support loading and management of scenery tiles. Note,
944 // there's still a fair amount of work left to be done.
946 // Revision 1.2 1998/01/08 02:22:27 curt
947 // Continue working on basic features.
949 // Revision 1.1 1998/01/07 23:50:51 curt
950 // "area" renamed to "tile"
952 // Revision 1.2 1998/01/07 03:29:29 curt
953 // Given an arbitrary lat/lon, we can now:
954 // generate a unique index for the chunk containing the lat/lon
955 // generate a path name to the chunk file
956 // build a list of the indexes of all the nearby areas.
958 // Revision 1.1 1998/01/07 02:05:48 curt