Pileus Git - grits/blob - src/roam.c

   1 /*
   2  * Copyright (C) 2009-2010 Andy Spencer <andy753421@gmail.com>
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 /**
  19  * SECTION:roam
  20  * @short_description: Realtime Optimally-Adapting Meshes
  21  *
  22  * A spherical version of the Realtime Optimally-Adapting Meshes (ROAM)
  23  * algorithm is use for drawing the surface of the planet. ROAM provide a
  24  * continuous level-of-detail mesh of the planet which is used by #GisOpenGL
  25  * when drawing surface textures for GisTiles.
  26  *
  27  * This implementation of the ROAM algorithm is based on an octahedron as the
  28  * base model.
  29  */
  30
  31 #include <glib.h>
  32 #include <math.h>
  33 #include <string.h>
  34 #include <GL/gl.h>
  35 #include <GL/glu.h>
  36
  37 #include "gpqueue.h"
  38 #include "gis-util.h"
  39 #include "roam.h"
  40
  41 /*
  42  * TODO:
  43  *   - Optimize for memory consumption
  44  *   - Profile for computation speed
  45  *   - Target polygon count/detail
  46  */
  47
  48 /* For GPQueue comparators */
  49 static gint tri_cmp(RoamTriangle *a, RoamTriangle *b, gpointer data)
  50 {
  51         if      (a->error < b->error) return  1;
  52         else if (a->error > b->error) return -1;
  53         else                          return  0;
  54 }
  55 static gint dia_cmp(RoamDiamond *a, RoamDiamond *b, gpointer data)
  56 {
  57         if      (a->error < b->error) return -1;
  58         else if (a->error > b->error) return  1;
  59         else                          return  0;
  60 }
  61
  62
  63 /*************
  64  * RoamPoint *
  65  *************/
  66 /**
  67  * roam_point_new:
  68  * @lat:  the latitude for the point
  69  * @lon:  the longitude for the point
  70  * @elev: the elevation for the point
  71  *
  72  * Create a new point at the given locaiton
  73  *
  74  * Returns: the new point
  75  */
  76 RoamPoint *roam_point_new(gdouble lat, gdouble lon, gdouble elev)
  77 {
  78         RoamPoint *point = g_new0(RoamPoint, 1);
  79         point->lat  = lat;
  80         point->lon  = lon;
  81         point->elev = elev;
  82         /* For get_intersect */
  83         lle2xyz(lat, lon, elev, &point->x, &point->y, &point->z);
  84         return point;
  85 }
  86
  87 /**
  88  * roam_point_add_triangle:
  89  * @point:    the point
  90  * @triangle: the to add
  91  *
  92  * Associating a triangle with a point and update it's vertex normal.
  93  */
  94 void roam_point_add_triangle(RoamPoint *point, RoamTriangle *triangle)
  95 {
  96         for (int i = 0; i < 3; i++) {
  97                 point->norm[i] *= point->tris;
  98                 point->norm[i] += triangle->norm[i];
  99         }
 100         point->tris++;
 101         for (int i = 0; i < 3; i++)
 102                 point->norm[i] /= point->tris;
 103 }
 104
 105 /**
 106  * roam_point_remove_triangle:
 107  * @point:    the point
 108  * @triangle: the to add
 109  *
 110  * Un-associating a triangle with a point and update it's vertex normal.
 111  */
 112 void roam_point_remove_triangle(RoamPoint *point, RoamTriangle *triangle)
 113 {
 114         for (int i = 0; i < 3; i++) {
 115                 point->norm[i] *= point->tris;
 116                 point->norm[i] -= triangle->norm[i];
 117         }
 118         point->tris--;
 119         if (point->tris)
 120                 for (int i = 0; i < 3; i++)
 121                         point->norm[i] /= point->tris;
 122 }
 123
 124 /**
 125  * roam_point_update_height:
 126  * @point: the point
 127  *
 128  * Update the height (elevation) of a point based on the current height function
 129  */
 130 void roam_point_update_height(RoamPoint *point)
 131 {
 132         if (point->height_func) {
 133                 gdouble elev = point->height_func(
 134                                 point->lat, point->lon, point->height_data);
 135                 lle2xyz(point->lat, point->lon, elev,
 136                                 &point->x, &point->y, &point->z);
 137         }
 138 }
 139
 140 /**
 141  * roam_point_update_projection:
 142  * @point: the point
 143  * @view:  the view to use when projecting the point
 144  *
 145  * Updated the screen-space projection of a point.
 146  */
 147 void roam_point_update_projection(RoamPoint *point, RoamView *view)
 148 {
 149         static int count   = 0;
 150         static int version = 0;
 151         if (version != view->version) {
 152                 g_debug("RoamPoint: Projected %d points", count);
 153                 count   = 0;
 154                 version = view->version;
 155         }
 156
 157         if (point->pversion != view->version) {
 158                 /* Cache projection */
 159                 gluProject(point->x, point->y, point->z,
 160                         view->model, view->proj, view->view,
 161                         &point->px, &point->py, &point->pz);
 162                 point->pversion = view->version;
 163                 count++;
 164         }
 165 }
 166
 167 /****************
 168  * RoamTriangle *
 169  ****************/
 170 /**
 171  * roam_triangle_new:
 172  * @l: the left point
 173  * @m: the middle point
 174  * @r: the right point
 175  *
 176  * Create a new triangle consisting of three points.
 177  *
 178  * Returns: the new triangle
 179  */
 180 RoamTriangle *roam_triangle_new(RoamPoint *l, RoamPoint *m, RoamPoint *r,
 181                 RoamDiamond *parent)
 182 {
 183         RoamTriangle *triangle = g_new0(RoamTriangle, 1);
 184
 185         triangle->error  = 0;
 186         triangle->p.l    = l;
 187         triangle->p.m    = m;
 188         triangle->p.r    = r;
 189         triangle->parent = parent;
 190         triangle->split  = roam_point_new(
 191                 (l->lat + r->lat)/2,
 192                 (ABS(l->lat) == 90 ? r->lon :
 193                  ABS(r->lat) == 90 ? l->lon :
 194                  lon_avg(l->lon, r->lon)),
 195                 (l->elev + r->elev)/2);
 196         /* TODO: Move this back to sphere, or actually use the nesting */
 197         triangle->split->height_func = m->height_func;
 198         triangle->split->height_data = m->height_data;
 199         roam_point_update_height(triangle->split);
 200         //if ((float)triangle->split->lat > 44 && (float)triangle->split->lat < 46)
 201         //      g_debug("RoamTriangle: new - (l,m,r,split).lats = %7.2f %7.2f %7.2f %7.2f",
 202         //                      l->lat, m->lat, r->lat, triangle->split->lat);
 203         //if ((float)l->lat == (float)r->lat &&
 204         //    (float)triangle->split->lat != (float)l->lat)
 205         //      g_warning("RoamTriangle: new - split.lat=%f != (l=r).lat=%f",
 206         //              triangle->split->lat, l->lat);
 207
 208         /* Update normal */
 209         double pa[3];
 210         double pb[3];
 211         pa[0] = triangle->p.l->x - triangle->p.m->x;
 212         pa[1] = triangle->p.l->y - triangle->p.m->y;
 213         pa[2] = triangle->p.l->z - triangle->p.m->z;
 214
 215         pb[0] = triangle->p.r->x - triangle->p.m->x;
 216         pb[1] = triangle->p.r->y - triangle->p.m->y;
 217         pb[2] = triangle->p.r->z - triangle->p.m->z;
 218
 219         triangle->norm[0] = pa[1] * pb[2] - pa[2] * pb[1];
 220         triangle->norm[1] = pa[2] * pb[0] - pa[0] * pb[2];
 221         triangle->norm[2] = pa[0] * pb[1] - pa[1] * pb[0];
 222
 223         double total = sqrt(triangle->norm[0] * triangle->norm[0] +
 224                             triangle->norm[1] * triangle->norm[1] +
 225                             triangle->norm[2] * triangle->norm[2]);
 226
 227         triangle->norm[0] /= total;
 228         triangle->norm[1] /= total;
 229         triangle->norm[2] /= total;
 230
 231         /* Store bounding box, for get_intersect */
 232         RoamPoint *p[] = {l,m,r};
 233         triangle->edge.n =  -90; triangle->edge.s =  90;
 234         triangle->edge.e = -180; triangle->edge.w = 180;
 235         gboolean maxed = FALSE;
 236         for (int i = 0; i < G_N_ELEMENTS(p); i++) {
 237                 triangle->edge.n = MAX(triangle->edge.n, p[i]->lat);
 238                 triangle->edge.s = MIN(triangle->edge.s, p[i]->lat);
 239                 if (p[i]->lat == 90 || p[i]->lat == -90)
 240                         continue;
 241                 if (p[i]->lon == 180) {
 242                         maxed = TRUE;
 243                         continue;
 244                 }
 245                 triangle->edge.e = MAX(triangle->edge.e, p[i]->lon);
 246                 triangle->edge.w = MIN(triangle->edge.w, p[i]->lon);
 247         }
 248         if (maxed) {
 249                 if (triangle->edge.e < 0)
 250                         triangle->edge.w = -180;
 251                 else
 252                         triangle->edge.e =  180;
 253         }
 254
 255         //g_message("roam_triangle_new: %p", triangle);
 256         return triangle;
 257 }
 258
 259 /**
 260  * roam_triangle_free:
 261  * @triangle: the triangle
 262  *
 263  * Free data associated with a triangle
 264  */
 265 void roam_triangle_free(RoamTriangle *triangle)
 266 {
 267         g_free(triangle->split);
 268         g_free(triangle);
 269 }
 270
 271 /**
 272  * roam_triangle_add:
 273  * @triangle: the triangle
 274  * @left:     the left neighbor
 275  * @base:     the base neighbor
 276  * @right:    the right neighbor
 277  * @sphere:   the sphere to add the triangle to
 278  *
 279  * Add a triangle into the sphere's mesh using the given neighbors.
 280  */
 281 void roam_triangle_add(RoamTriangle *triangle,
 282                 RoamTriangle *left, RoamTriangle *base, RoamTriangle *right,
 283                 RoamSphere *sphere)
 284 {
 285         triangle->t.l = left;
 286         triangle->t.b = base;
 287         triangle->t.r = right;
 288
 289         roam_point_add_triangle(triangle->p.l, triangle);
 290         roam_point_add_triangle(triangle->p.m, triangle);
 291         roam_point_add_triangle(triangle->p.r, triangle);
 292
 293         if (sphere->view)
 294                 roam_triangle_update_errors(triangle, sphere);
 295
 296         triangle->handle = g_pqueue_push(sphere->triangles, triangle);
 297 }
 298
 299 /**
 300  * roam_triangle_remove:
 301  * @triangle: the triangle
 302  * @sphere:   the sphere to remove the triangle from
 303  *
 304  * Remove a triangle from a sphere's mesh.
 305  */
 306 void roam_triangle_remove(RoamTriangle *triangle, RoamSphere *sphere)
 307 {
 308         /* Update vertex normals */
 309         roam_point_remove_triangle(triangle->p.l, triangle);
 310         roam_point_remove_triangle(triangle->p.m, triangle);
 311         roam_point_remove_triangle(triangle->p.r, triangle);
 312
 313         g_pqueue_remove(sphere->triangles, triangle->handle);
 314 }
 315
 316 /* (neight->t.? == old) = new */
 317 static void roam_triangle_sync_neighbors(RoamTriangle *neigh, RoamTriangle *old, RoamTriangle *new)
 318 {
 319         if      (neigh->t.l == old) neigh->t.l = new;
 320         else if (neigh->t.b == old) neigh->t.b = new;
 321         else if (neigh->t.r == old) neigh->t.r = new;
 322 }
 323
 324 static gboolean roam_triangle_visible(RoamTriangle *triangle, RoamSphere *sphere)
 325 {
 326         RoamPoint *l = triangle->p.l;
 327         RoamPoint *m = triangle->p.m;
 328         RoamPoint *r = triangle->p.r;
 329         gdouble min_x = MIN(MIN(l->px, m->px), r->px);
 330         gdouble max_x = MAX(MAX(l->px, m->px), r->px);
 331         gdouble min_y = MIN(MIN(l->py, m->py), r->py);
 332         gdouble max_y = MAX(MAX(l->py, m->py), r->py);
 333         gint *view = sphere->view->view;
 334         return !(max_x < view[0] || min_x > view[2] ||
 335                  max_y < view[1] || min_y > view[3]) &&
 336                  l->pz > 0 && m->pz > 0 && r->pz > 0 &&
 337                  l->pz < 1 && m->pz < 1 && r->pz < 1;
 338 }
 339
 340 static gboolean roam_triangle_backface(RoamTriangle *triangle, RoamSphere *sphere)
 341 {
 342         RoamPoint *l = triangle->p.l;
 343         RoamPoint *m = triangle->p.m;
 344         RoamPoint *r = triangle->p.r;
 345         roam_point_update_projection(l, sphere->view);
 346         roam_point_update_projection(m, sphere->view);
 347         roam_point_update_projection(r, sphere->view);
 348         double size = -( l->px * (m->py - r->py) +
 349                          m->px * (r->py - l->py) +
 350                          r->px * (l->py - m->py) ) / 2.0;
 351         return size < 0;
 352 }
 353
 354 /**
 355  * roam_triangle_update_errors:
 356  * @triangle: the triangle
 357  * @sphere:   the sphere to use when updating errors
 358  *
 359  * Update the error value associated with a triangle. Called when the view
 360  * changes.
 361  */
 362 void roam_triangle_update_errors(RoamTriangle *triangle, RoamSphere *sphere)
 363 {
 364 #if 0
 365         /* Update points */
 366         roam_point_update_projection(triangle->p.l, sphere->view);
 367         roam_point_update_projection(triangle->p.m, sphere->view);
 368         roam_point_update_projection(triangle->p.r, sphere->view);
 369
 370         if (!roam_triangle_visible(triangle, sphere)) {
 371                 triangle->error = -1;
 372         } else {
 373                 roam_point_update_projection(triangle->split, sphere->view);
 374                 RoamPoint *l     = triangle->p.l;
 375                 RoamPoint *m     = triangle->p.m;
 376                 RoamPoint *r     = triangle->p.r;
 377                 RoamPoint *split = triangle->split;
 378
 379                 /*               l-r midpoint        projected l-r midpoint */
 380                 gdouble pxdist = (l->px + r->px)/2 - split->px;
 381                 gdouble pydist = (l->py + r->py)/2 - split->py;
 382
 383                 triangle->error = sqrt(pxdist*pxdist + pydist*pydist);
 384
 385                 /* Multiply by size of triangle */
 386                 double size = -( l->px * (m->py - r->py) +
 387                                  m->px * (r->py - l->py) +
 388                                  r->px * (l->py - m->py) ) / 2.0;
 389
 390                 /* Size < 0 == backface */
 391                 triangle->error *= size;
 392
 393                 /* Give some preference to "edge" faces */
 394                 if (roam_triangle_backface(triangle->t.l, sphere) ||
 395                     roam_triangle_backface(triangle->t.b, sphere) ||
 396                     roam_triangle_backface(triangle->t.r, sphere))
 397                         triangle->error *= 500;
 398         }
 399 #endif
 400
 401         /* For pure distance based errors */
 402         (void)roam_triangle_visible;
 403         (void)roam_triangle_backface;
 404         RoamPoint *l = triangle->p.l;
 405         RoamPoint *m = triangle->p.m;
 406         RoamPoint *r = triangle->p.r;
 407         double base = distd((gdouble*)l, (gdouble*)r);
 408         double dist = distd((gdouble*)m, (gdouble*)sphere->view->pos);
 409         triangle->error = base/dist;
 410 }
 411
 412 /**
 413  * roam_triangle_split:
 414  * @triangle: the triangle
 415  * @sphere:   the sphere
 416  *
 417  * Split a triangle into two child triangles and update the sphere.
 418  * triangle
 419  */
 420 void roam_triangle_split(RoamTriangle *triangle, RoamSphere *sphere)
 421 {
 422         //g_message("roam_triangle_split: %p, e=%f\n", triangle, triangle->error);
 423
 424         sphere->polys += 2;
 425
 426         if (triangle != triangle->t.b->t.b)
 427                 roam_triangle_split(triangle->t.b, sphere);
 428         if (triangle != triangle->t.b->t.b)
 429                 g_assert_not_reached();
 430
 431         RoamTriangle *s = triangle;      // Self
 432         RoamTriangle *b = triangle->t.b; // Base
 433
 434         RoamDiamond *dia = roam_diamond_new(s, b);
 435
 436         /* Add new triangles */
 437         RoamPoint *mid = triangle->split;
 438         RoamTriangle *sl = s->kids[0] = roam_triangle_new(s->p.m, mid, s->p.l, dia); // Self Left
 439         RoamTriangle *sr = s->kids[1] = roam_triangle_new(s->p.r, mid, s->p.m, dia); // Self Right
 440         RoamTriangle *bl = b->kids[0] = roam_triangle_new(b->p.m, mid, b->p.l, dia); // Base Left
 441         RoamTriangle *br = b->kids[1] = roam_triangle_new(b->p.r, mid, b->p.m, dia); // Base Right
 442
 443         /*                triangle,l,  base,      r,  sphere */
 444         roam_triangle_add(sl, sr, s->t.l, br, sphere);
 445         roam_triangle_add(sr, bl, s->t.r, sl, sphere);
 446         roam_triangle_add(bl, br, b->t.l, sr, sphere);
 447         roam_triangle_add(br, sl, b->t.r, bl, sphere);
 448
 449         roam_triangle_sync_neighbors(s->t.l, s, sl);
 450         roam_triangle_sync_neighbors(s->t.r, s, sr);
 451         roam_triangle_sync_neighbors(b->t.l, b, bl);
 452         roam_triangle_sync_neighbors(b->t.r, b, br);
 453
 454         /* Remove old triangles */
 455         roam_triangle_remove(s, sphere);
 456         roam_triangle_remove(b, sphere);
 457
 458         /* Add/Remove diamonds */
 459         roam_diamond_update_errors(dia, sphere);
 460         roam_diamond_add(dia, sphere);
 461         roam_diamond_remove(s->parent, sphere);
 462         roam_diamond_remove(b->parent, sphere);
 463 }
 464
 465 /**
 466  * roam_triangle_draw:
 467  * @triangle: the triangle
 468  *
 469  * Draw the triangle. Use for debugging.
 470  */
 471 void roam_triangle_draw(RoamTriangle *triangle)
 472 {
 473         glBegin(GL_TRIANGLES);
 474         glNormal3dv(triangle->p.r->norm); glVertex3dv((double*)triangle->p.r);
 475         glNormal3dv(triangle->p.m->norm); glVertex3dv((double*)triangle->p.m);
 476         glNormal3dv(triangle->p.l->norm); glVertex3dv((double*)triangle->p.l);
 477         glEnd();
 478         return;
 479 }
 480
 481 /**
 482  * roam_triangle_draw_normal:
 483  * @triangle: the triangle
 484  *
 485  * Draw a normal vector for the triangle. Used while debugging.
 486  */
 487 void roam_triangle_draw_normal(RoamTriangle *triangle)
 488 {
 489         double center[] = {
 490                 (triangle->p.l->x + triangle->p.m->x + triangle->p.r->x)/3.0,
 491                 (triangle->p.l->y + triangle->p.m->y + triangle->p.r->y)/3.0,
 492                 (triangle->p.l->z + triangle->p.m->z + triangle->p.r->z)/3.0,
 493         };
 494         double end[] = {
 495                 center[0]+triangle->norm[0]*2000000,
 496                 center[1]+triangle->norm[1]*2000000,
 497                 center[2]+triangle->norm[2]*2000000,
 498         };
 499         glBegin(GL_LINES);
 500         glVertex3dv(center);
 501         glVertex3dv(end);
 502         glEnd();
 503 }
 504
 505 /***************
 506  * RoamDiamond *
 507  ***************/
 508 /**
 509  * roam_diamond_new:
 510  * @parent0: a parent triangle
 511  * @parent1: a parent triangle
 512  * @kid0:    a child triangle
 513  * @kid1:    a child triangle
 514  * @kid2:    a child triangle
 515  * @kid3:    a child triangle
 516  *
 517  * Create a diamond to store information about two split triangles.
 518  *
 519  * Returns: the new diamond
 520  */
 521 RoamDiamond *roam_diamond_new(RoamTriangle *parent0, RoamTriangle *parent1)
 522 {
 523         RoamDiamond *diamond = g_new0(RoamDiamond, 1);
 524         diamond->parents[0] = parent0;
 525         diamond->parents[1] = parent1;
 526         return diamond;
 527 }
 528
 529 /**
 530  * roam_diamond_add:
 531  * @diamond: the diamond
 532  * @sphere:  the sphere to add the diamond to
 533  *
 534  * Add a diamond into the sphere's pool of diamonds. It will be check for
 535  * possible merges.
 536  */
 537 void roam_diamond_add(RoamDiamond *diamond, RoamSphere *sphere)
 538 {
 539         diamond->active = TRUE;
 540         diamond->error  = MAX(diamond->parents[0]->error, diamond->parents[1]->error);
 541         diamond->handle = g_pqueue_push(sphere->diamonds, diamond);
 542 }
 543
 544 /**
 545  * roam_diamond_remove:
 546  * @diamond: the diamond
 547  * @sphere:  the sphere to remove the diamond from
 548  *
 549  * Remove a diamond from the sphere's pool of diamonds.
 550  */
 551 void roam_diamond_remove(RoamDiamond *diamond, RoamSphere *sphere)
 552 {
 553         if (diamond && diamond->active) {
 554                 diamond->active = FALSE;
 555                 g_pqueue_remove(sphere->diamonds, diamond->handle);
 556         }
 557 }
 558
 559 /**
 560  * roam_diamond_merge:
 561  * @diamond: the diamond
 562  * @sphere:  the sphere
 563  *
 564  * "Merge" a diamond back into two parent triangles. The original two triangles
 565  * are added back into the sphere and the four child triangles as well as the
 566  * diamond are removed.
 567  */
 568 void roam_diamond_merge(RoamDiamond *diamond, RoamSphere *sphere)
 569 {
 570         //g_message("roam_diamond_merge: %p, e=%f\n", diamond, diamond->error);
 571
 572         /* TODO: pick the best split */
 573         sphere->polys -= 2;
 574
 575         /* Use nicer temp names */
 576         RoamTriangle *s = diamond->parents[0]; // Self
 577         RoamTriangle *b = diamond->parents[1]; // Base
 578
 579         RoamTriangle *sl = s->kids[0];
 580         RoamTriangle *sr = s->kids[1];
 581         RoamTriangle *bl = b->kids[0];
 582         RoamTriangle *br = b->kids[1];
 583
 584         s->kids[0] = s->kids[1] = NULL;
 585         b->kids[0] = b->kids[1] = NULL;
 586
 587         /* Add original triangles */
 588         roam_triangle_sync_neighbors(s->t.l, sl, s);
 589         roam_triangle_sync_neighbors(s->t.r, sr, s);
 590         roam_triangle_sync_neighbors(b->t.l, bl, b);
 591         roam_triangle_sync_neighbors(b->t.r, br, b);
 592
 593         roam_triangle_add(s, sl->t.b, b, sr->t.b, sphere);
 594         roam_triangle_add(b, bl->t.b, s, br->t.b, sphere);
 595
 596         roam_triangle_sync_neighbors(sl->t.b, sl, s);
 597         roam_triangle_sync_neighbors(sr->t.b, sr, s);
 598         roam_triangle_sync_neighbors(bl->t.b, bl, b);
 599         roam_triangle_sync_neighbors(br->t.b, br, b);
 600
 601         /* Remove child triangles */
 602         roam_triangle_remove(sl, sphere);
 603         roam_triangle_remove(sr, sphere);
 604         roam_triangle_remove(bl, sphere);
 605         roam_triangle_remove(br, sphere);
 606
 607         /* Add/Remove triangles */
 608         if (s->t.l->t.l == s->t.r->t.r &&
 609             s->t.l->t.l != s && s->parent) {
 610                 roam_diamond_update_errors(s->parent, sphere);
 611                 roam_diamond_add(s->parent, sphere);
 612         }
 613
 614         if (b->t.l->t.l == b->t.r->t.r &&
 615             b->t.l->t.l != b && b->parent) {
 616                 roam_diamond_update_errors(b->parent, sphere);
 617                 roam_diamond_add(b->parent, sphere);
 618         }
 619
 620         /* Remove and free diamond and child triangles */
 621         roam_diamond_remove(diamond, sphere);
 622         g_assert(sl->p.m == sr->p.m &&
 623                  sr->p.m == bl->p.m &&
 624                  bl->p.m == br->p.m);
 625         g_assert(sl->p.m->tris == 0);
 626         roam_triangle_free(sl);
 627         roam_triangle_free(sr);
 628         roam_triangle_free(bl);
 629         roam_triangle_free(br);
 630         g_free(diamond);
 631 }
 632
 633 /**
 634  * roam_diamond_update_errors:
 635  * @diamond: the diamond
 636  * @sphere:  the sphere to use when updating errors
 637  *
 638  * Update the error value associated with a diamond. Called when the view
 639  * changes.
 640  */
 641 void roam_diamond_update_errors(RoamDiamond *diamond, RoamSphere *sphere)
 642 {
 643         roam_triangle_update_errors(diamond->parents[0], sphere);
 644         roam_triangle_update_errors(diamond->parents[1], sphere);
 645         diamond->error = MAX(diamond->parents[0]->error, diamond->parents[1]->error);
 646 }
 647
 648 /**************
 649  * RoamSphere *
 650  **************/
 651 /**
 652  * roam_sphere_new:
 653  *
 654  * Create a new sphere
 655  *
 656  * Returns: the sphere
 657  */
 658 RoamSphere *roam_sphere_new()
 659 {
 660         RoamSphere *sphere = g_new0(RoamSphere, 1);
 661         sphere->polys       = 8;
 662         sphere->triangles   = g_pqueue_new((GCompareDataFunc)tri_cmp, NULL);
 663         sphere->diamonds    = g_pqueue_new((GCompareDataFunc)dia_cmp, NULL);
 664
 665         RoamPoint *vertexes[] = {
 666                 roam_point_new( 90,   0,  0), // 0 (North)
 667                 roam_point_new(-90,   0,  0), // 1 (South)
 668                 roam_point_new(  0,   0,  0), // 2 (Europe/Africa)
 669                 roam_point_new(  0,  90,  0), // 3 (Asia,East)
 670                 roam_point_new(  0, 180,  0), // 4 (Pacific)
 671                 roam_point_new(  0, -90,  0), // 5 (Americas,West)
 672         };
 673         int _triangles[][2][3] = {
 674                 /*lv mv rv   ln, bn, rn */
 675                 {{2,0,3}, {3, 4, 1}}, // 0
 676                 {{3,0,4}, {0, 5, 2}}, // 1
 677                 {{4,0,5}, {1, 6, 3}}, // 2
 678                 {{5,0,2}, {2, 7, 0}}, // 3
 679                 {{3,1,2}, {5, 0, 7}}, // 4
 680                 {{4,1,3}, {6, 1, 4}}, // 5
 681                 {{5,1,4}, {7, 2, 5}}, // 6
 682                 {{2,1,5}, {4, 3, 6}}, // 7
 683         };
 684
 685         for (int i = 0; i < 6; i++)
 686                 roam_point_update_height(vertexes[i]);
 687         for (int i = 0; i < 8; i++)
 688                 sphere->roots[i] = roam_triangle_new(
 689                         vertexes[_triangles[i][0][0]],
 690                         vertexes[_triangles[i][0][1]],
 691                         vertexes[_triangles[i][0][2]],
 692                         NULL);
 693         for (int i = 0; i < 8; i++)
 694                 roam_triangle_add(sphere->roots[i],
 695                         sphere->roots[_triangles[i][1][0]],
 696                         sphere->roots[_triangles[i][1][1]],
 697                         sphere->roots[_triangles[i][1][2]],
 698                         sphere);
 699         for (int i = 0; i < 8; i++)
 700                 g_debug("RoamSphere: new - %p edge=%f,%f,%f,%f", sphere->roots[i],
 701                                 sphere->roots[i]->edge.n,
 702                                 sphere->roots[i]->edge.s,
 703                                 sphere->roots[i]->edge.e,
 704                                 sphere->roots[i]->edge.w);
 705
 706         return sphere;
 707 }
 708
 709 /**
 710  * roam_sphere_update_view
 711  * @sphere: the sphere
 712  *
 713  * Recreate the sphere's view matrices based on the current OpenGL state.
 714  */
 715 void roam_sphere_update_view(RoamSphere *sphere)
 716 {
 717         if (!sphere->view)
 718                 sphere->view = g_new0(RoamView, 1);
 719         glGetDoublev (GL_MODELVIEW_MATRIX,  sphere->view->model);
 720         glGetDoublev (GL_PROJECTION_MATRIX, sphere->view->proj);
 721         glGetIntegerv(GL_VIEWPORT,          sphere->view->view);
 722         sphere->view->version++;
 723 }
 724
 725 /**
 726  * roam_sphere_update_errors
 727  * @sphere: the sphere
 728  *
 729  * Update triangle and diamond errors in the sphere.
 730  */
 731 void roam_sphere_update_errors(RoamSphere *sphere)
 732 {
 733         g_debug("RoamSphere: update_errors - polys=%d", sphere->polys);
 734         GPtrArray *tris = g_pqueue_get_array(sphere->triangles);
 735         GPtrArray *dias = g_pqueue_get_array(sphere->diamonds);
 736
 737         roam_sphere_update_view(sphere);
 738
 739         for (int i = 0; i < tris->len; i++) {
 740                 RoamTriangle *triangle = tris->pdata[i];
 741                 roam_triangle_update_errors(triangle, sphere);
 742                 g_pqueue_priority_changed(sphere->triangles, triangle->handle);
 743         }
 744
 745         for (int i = 0; i < dias->len; i++) {
 746                 RoamDiamond *diamond = dias->pdata[i];
 747                 roam_diamond_update_errors(diamond, sphere);
 748                 g_pqueue_priority_changed(sphere->diamonds, diamond->handle);
 749         }
 750
 751         g_ptr_array_free(tris, TRUE);
 752         g_ptr_array_free(dias, TRUE);
 753 }
 754
 755 /**
 756  * roam_sphere_split_one
 757  * @sphere: the sphere
 758  *
 759  * Split the triangle with the greatest error.
 760  */
 761 void roam_sphere_split_one(RoamSphere *sphere)
 762 {
 763         RoamTriangle *to_split = g_pqueue_peek(sphere->triangles);
 764         if (!to_split) return;
 765         roam_triangle_split(to_split, sphere);
 766 }
 767
 768 /**
 769  * roam_sphere_merge_one
 770  * @sphere: the sphere
 771  *
 772  * Merge the diamond with the lowest error.
 773  */
 774 void roam_sphere_merge_one(RoamSphere *sphere)
 775 {
 776         RoamDiamond *to_merge = g_pqueue_peek(sphere->diamonds);
 777         if (!to_merge) return;
 778         roam_diamond_merge(to_merge, sphere);
 779 }
 780
 781 /**
 782  * roam_sphere_split_merge
 783  * @sphere: the sphere
 784  *
 785  * Perform a predetermined number split-merge iterations.
 786  *
 787  * Returns: the number splits and merges done
 788  */
 789 gint roam_sphere_split_merge(RoamSphere *sphere)
 790 {
 791         gint iters = 0, max_iters = 500;
 792         gint target = 10000;
 793         //gint target = 4000;
 794         //gint target = 2000;
 795         //gint target = 500;
 796
 797         if (!sphere->view)
 798                 return 0;
 799
 800         if (target - sphere->polys > 100) {
 801                 //g_debug("RoamSphere: split_merge - Splitting %d - %d > 100", target, sphere->polys);
 802                 while (sphere->polys < target && iters++ < max_iters)
 803                         roam_sphere_split_one(sphere);
 804         }
 805
 806         if (sphere->polys - target > 100) {
 807                 //g_debug("RoamSphere: split_merge - Merging %d - %d > 100", sphere->polys, target);
 808                 while (sphere->polys > target && iters++ < max_iters)
 809                         roam_sphere_merge_one(sphere);
 810         }
 811
 812         while (((RoamTriangle*)g_pqueue_peek(sphere->triangles))->error >
 813                ((RoamDiamond *)g_pqueue_peek(sphere->diamonds ))->error &&
 814                iters++ < max_iters) {
 815                 //g_debug("RoamSphere: split_merge - Fixing 1 %f > %f && %d < %d",
 816                 //              ((RoamTriangle*)g_pqueue_peek(sphere->triangles))->error,
 817                 //              ((RoamDiamond *)g_pqueue_peek(sphere->diamonds ))->error,
 818                 //              iters-1, max_iters);
 819                 roam_sphere_merge_one(sphere);
 820                 roam_sphere_split_one(sphere);
 821         }
 822
 823         return iters;
 824 }
 825
 826 /**
 827  * roam_sphere_draw:
 828  * @sphere: the sphere
 829  *
 830  * Draw the sphere. Use for debugging.
 831  */
 832 void roam_sphere_draw(RoamSphere *sphere)
 833 {
 834         g_debug("RoamSphere: draw");
 835         g_pqueue_foreach(sphere->triangles, (GFunc)roam_triangle_draw, NULL);
 836 }
 837
 838 /**
 839  * roam_sphere_draw_normals
 840  * @sphere: the sphere
 841  *
 842  * Draw all the surface normal vectors for the sphere. Used while debugging.
 843  */
 844 void roam_sphere_draw_normals(RoamSphere *sphere)
 845 {
 846         g_debug("RoamSphere: draw_normal");
 847         g_pqueue_foreach(sphere->triangles, (GFunc)roam_triangle_draw_normal, NULL);
 848 }
 849
 850 static GList *_roam_sphere_get_leaves(RoamTriangle *triangle, GList *list, gboolean all)
 851 {
 852         if (triangle->kids[0] && triangle->kids[1]) {
 853                 if (all) list = g_list_prepend(list, triangle);
 854                 list = _roam_sphere_get_leaves(triangle->kids[0], list, all);
 855                 list = _roam_sphere_get_leaves(triangle->kids[1], list, all);
 856                 return list;
 857         } else {
 858                 return g_list_prepend(list, triangle);
 859         }
 860 }
 861
 862 static GList *_roam_sphere_get_intersect_rec(RoamTriangle *triangle, GList *list,
 863                 gboolean all, gdouble n, gdouble s, gdouble e, gdouble w)
 864 {
 865         gdouble tn = triangle->edge.n;
 866         gdouble ts = triangle->edge.s;
 867         gdouble te = triangle->edge.e;
 868         gdouble tw = triangle->edge.w;
 869
 870         gboolean debug = FALSE  &&
 871                 n==90 && s==45 && e==-90 && w==-180 &&
 872                 ts > 44 && ts < 46;
 873
 874         if (debug)
 875                 g_message("t=%p: %f < %f || %f > %f || %f < %f || %f > %f",
 876                             triangle, tn,   s,   ts,   n,   te,   w,   tw,   e);
 877         if (tn <= s || ts >= n || te <= w || tw >= e) {
 878                 /* No intersect */
 879                 if (debug) g_message("no intersect");
 880                 return list;
 881         } else if (tn <= n && ts >= s && te <= e && tw >= w) {
 882                 /* Triangle is completely contained */
 883                 if (debug) g_message("contained");
 884                 if (all) list = g_list_prepend(list, triangle);
 885                 return _roam_sphere_get_leaves(triangle, list, all);
 886         } else if (triangle->kids[0] && triangle->kids[1]) {
 887                 /* Paritial intersect with children */
 888                 if (debug) g_message("edge w/ child");
 889                 if (all) list = g_list_prepend(list, triangle);
 890                 list = _roam_sphere_get_intersect_rec(triangle->kids[0], list, all, n, s, e, w);
 891                 list = _roam_sphere_get_intersect_rec(triangle->kids[1], list, all, n, s, e, w);
 892                 return list;
 893         } else {
 894                 /* This triangle is an edge case */
 895                 if (debug) g_message("edge");
 896                 return g_list_prepend(list, triangle);
 897         }
 898 }
 899
 900 /**
 901  * roam_sphere_get_intersect
 902  * @sphere: the sphere
 903  * @all: TRUE if non-leaf triangle should be returned as well
 904  * @n: the northern edge
 905  * @s: the southern edge
 906  * @e: the eastern edge
 907  * @w: the western edge
 908  *
 909  * Lookup triangles withing the sphere that intersect a given lat-lon box.
 910  *
 911  * Returns: the list of intersecting triangles.
 912  */
 913 /* Warning: This grabs pointers to triangles which can be changed by other
 914  * calls, e.g. split_merge. If you use this, you need to do some locking to
 915  * prevent the returned list from becomming stale. */
 916 GList *roam_sphere_get_intersect(RoamSphere *sphere, gboolean all,
 917                 gdouble n, gdouble s, gdouble e, gdouble w)
 918 {
 919         /* I think this is correct..
 920          * i_cost = cost for triangle-rectagnle intersect test
 921          * time = n_tiles * 2*tris_per_tile * i_cost
 922          * time = 30      * 2*333           * i_cost = 20000 * i_cost */
 923         GList *list = NULL;
 924         for (int i = 0; i < G_N_ELEMENTS(sphere->roots); i++)
 925                 list = _roam_sphere_get_intersect_rec(sphere->roots[i],
 926                                 list, all, n, s, e, w);
 927         return list;
 928 }
 929
 930 static void roam_sphere_free_tri(RoamTriangle *triangle)
 931 {
 932         if (--triangle->p.l->tris == 0) g_free(triangle->p.l);
 933         if (--triangle->p.m->tris == 0) g_free(triangle->p.m);
 934         if (--triangle->p.r->tris == 0) g_free(triangle->p.r);
 935         roam_triangle_free(triangle);
 936 }
 937
 938 /**
 939  * roam_sphere_free
 940  * @sphere: the sphere
 941  *
 942  * Free data associated with a sphere
 943  */
 944 void roam_sphere_free(RoamSphere *sphere)
 945 {
 946         g_debug("RoamSphere: free");
 947         /* Slow method, but it should work */
 948         while (sphere->polys > 8)
 949                 roam_sphere_merge_one(sphere);
 950         /* TODO: free points */
 951         g_pqueue_foreach(sphere->triangles, (GFunc)roam_sphere_free_tri, NULL);
 952         g_pqueue_free(sphere->triangles);
 953         g_pqueue_free(sphere->diamonds);
 954         g_free(sphere->view);
 955         g_free(sphere);
 956 }