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 {
 182         RoamTriangle *triangle = g_new0(RoamTriangle, 1);
 183
 184         triangle->error = 0;
 185         triangle->p.l = l;
 186         triangle->p.m = m;
 187         triangle->p.r = r;
 188         triangle->split = roam_point_new(
 189                 (l->lat + r->lat)/2,
 190                 (ABS(l->lat) == 90 ? r->lon :
 191                  ABS(r->lat) == 90 ? l->lon :
 192                  lon_avg(l->lon, r->lon)),
 193                 (l->elev + r->elev)/2);
 194         /* TODO: Move this back to sphere, or actually use the nesting */
 195         triangle->split->height_func = m->height_func;
 196         triangle->split->height_data = m->height_data;
 197         roam_point_update_height(triangle->split);
 198         //if ((float)triangle->split->lat > 44 && (float)triangle->split->lat < 46)
 199         //      g_debug("RoamTriangle: new - (l,m,r,split).lats = %7.2f %7.2f %7.2f %7.2f",
 200         //                      l->lat, m->lat, r->lat, triangle->split->lat);
 201         //if ((float)l->lat == (float)r->lat &&
 202         //    (float)triangle->split->lat != (float)l->lat)
 203         //      g_warning("RoamTriangle: new - split.lat=%f != (l=r).lat=%f",
 204         //              triangle->split->lat, l->lat);
 205
 206         /* Update normal */
 207         double pa[3];
 208         double pb[3];
 209         pa[0] = triangle->p.l->x - triangle->p.m->x;
 210         pa[1] = triangle->p.l->y - triangle->p.m->y;
 211         pa[2] = triangle->p.l->z - triangle->p.m->z;
 212
 213         pb[0] = triangle->p.r->x - triangle->p.m->x;
 214         pb[1] = triangle->p.r->y - triangle->p.m->y;
 215         pb[2] = triangle->p.r->z - triangle->p.m->z;
 216
 217         triangle->norm[0] = pa[1] * pb[2] - pa[2] * pb[1];
 218         triangle->norm[1] = pa[2] * pb[0] - pa[0] * pb[2];
 219         triangle->norm[2] = pa[0] * pb[1] - pa[1] * pb[0];
 220
 221         double total = sqrt(triangle->norm[0] * triangle->norm[0] +
 222                             triangle->norm[1] * triangle->norm[1] +
 223                             triangle->norm[2] * triangle->norm[2]);
 224
 225         triangle->norm[0] /= total;
 226         triangle->norm[1] /= total;
 227         triangle->norm[2] /= total;
 228
 229         /* Store bounding box, for get_intersect */
 230         RoamPoint *p[] = {l,m,r};
 231         triangle->edge.n =  -90; triangle->edge.s =  90;
 232         triangle->edge.e = -180; triangle->edge.w = 180;
 233         gboolean maxed = FALSE;
 234         for (int i = 0; i < G_N_ELEMENTS(p); i++) {
 235                 triangle->edge.n = MAX(triangle->edge.n, p[i]->lat);
 236                 triangle->edge.s = MIN(triangle->edge.s, p[i]->lat);
 237                 if (p[i]->lat == 90 || p[i]->lat == -90)
 238                         continue;
 239                 if (p[i]->lon == 180) {
 240                         maxed = TRUE;
 241                         continue;
 242                 }
 243                 triangle->edge.e = MAX(triangle->edge.e, p[i]->lon);
 244                 triangle->edge.w = MIN(triangle->edge.w, p[i]->lon);
 245         }
 246         if (maxed) {
 247                 if (triangle->edge.e < 0)
 248                         triangle->edge.w = -180;
 249                 else
 250                         triangle->edge.e =  180;
 251         }
 252
 253         //g_message("roam_triangle_new: %p", triangle);
 254         return triangle;
 255 }
 256
 257 /**
 258  * roam_triangle_free:
 259  * @triangle: the triangle
 260  *
 261  * Free data associated with a triangle
 262  */
 263 void roam_triangle_free(RoamTriangle *triangle)
 264 {
 265         g_free(triangle->split);
 266         g_free(triangle);
 267 }
 268
 269 /**
 270  * roam_triangle_add:
 271  * @triangle: the triangle
 272  * @left:     the left neighbor
 273  * @base:     the base neighbor
 274  * @right:    the right neighbor
 275  * @sphere:   the sphere to add the triangle to
 276  *
 277  * Add a triangle into the sphere's mesh using the given neighbors.
 278  */
 279 void roam_triangle_add(RoamTriangle *triangle,
 280                 RoamTriangle *left, RoamTriangle *base, RoamTriangle *right,
 281                 RoamSphere *sphere)
 282 {
 283         triangle->t.l = left;
 284         triangle->t.b = base;
 285         triangle->t.r = right;
 286
 287         roam_point_add_triangle(triangle->p.l, triangle);
 288         roam_point_add_triangle(triangle->p.m, triangle);
 289         roam_point_add_triangle(triangle->p.r, triangle);
 290
 291         if (sphere->view)
 292                 roam_triangle_update_errors(triangle, sphere);
 293
 294         triangle->handle = g_pqueue_push(sphere->triangles, triangle);
 295 }
 296
 297 /**
 298  * roam_triangle_remove:
 299  * @triangle: the triangle
 300  * @sphere:   the sphere to remove the triangle from
 301  *
 302  * Remove a triangle from a sphere's mesh.
 303  */
 304 void roam_triangle_remove(RoamTriangle *triangle, RoamSphere *sphere)
 305 {
 306         /* Update vertex normals */
 307         roam_point_remove_triangle(triangle->p.l, triangle);
 308         roam_point_remove_triangle(triangle->p.m, triangle);
 309         roam_point_remove_triangle(triangle->p.r, triangle);
 310
 311         g_pqueue_remove(sphere->triangles, triangle->handle);
 312 }
 313
 314 static void roam_triangle_sync_neighbors(RoamTriangle *new, RoamTriangle *old, RoamTriangle *neigh)
 315 {
 316         if      (neigh->t.l == old) neigh->t.l = new;
 317         else if (neigh->t.b == old) neigh->t.b = new;
 318         else if (neigh->t.r == old) neigh->t.r = new;
 319         else g_assert_not_reached();
 320 }
 321
 322 static gboolean roam_triangle_visible(RoamTriangle *triangle, RoamSphere *sphere)
 323 {
 324         RoamPoint *l = triangle->p.l;
 325         RoamPoint *m = triangle->p.m;
 326         RoamPoint *r = triangle->p.r;
 327         gdouble min_x = MIN(MIN(l->px, m->px), r->px);
 328         gdouble max_x = MAX(MAX(l->px, m->px), r->px);
 329         gdouble min_y = MIN(MIN(l->py, m->py), r->py);
 330         gdouble max_y = MAX(MAX(l->py, m->py), r->py);
 331         gint *view = sphere->view->view;
 332         return !(max_x < view[0] || min_x > view[2] ||
 333                  max_y < view[1] || min_y > view[3]) &&
 334                  l->pz > 0 && m->pz > 0 && r->pz > 0 &&
 335                  l->pz < 1 && m->pz < 1 && r->pz < 1;
 336 }
 337
 338 /**
 339  * roam_triangle_update_errors:
 340  * @triangle: the triangle
 341  * @sphere:   the sphere to use when updating errors
 342  *
 343  * Update the error value associated with a triangle. Called when the view
 344  * changes.
 345  */
 346 void roam_triangle_update_errors(RoamTriangle *triangle, RoamSphere *sphere)
 347 {
 348         /* Update points */
 349         roam_point_update_projection(triangle->p.l, sphere->view);
 350         roam_point_update_projection(triangle->p.m, sphere->view);
 351         roam_point_update_projection(triangle->p.r, sphere->view);
 352
 353         if (!roam_triangle_visible(triangle, sphere)) {
 354                 triangle->error = -1;
 355         } else {
 356                 roam_point_update_projection(triangle->split, sphere->view);
 357                 RoamPoint *l = triangle->p.l;
 358                 RoamPoint *m = triangle->p.m;
 359                 RoamPoint *r = triangle->p.r;
 360                 RoamPoint *split = triangle->split;
 361
 362                 /*               l-r midpoint        projected l-r midpoint */
 363                 gdouble pxdist = (l->px + r->px)/2 - split->px;
 364                 gdouble pydist = (l->py + r->py)/2 - split->py;
 365
 366                 triangle->error = sqrt(pxdist*pxdist + pydist*pydist);
 367
 368                 /* Multiply by size of triangle */
 369                 double size = -( l->px * (m->py - r->py) +
 370                                  m->px * (r->py - l->py) +
 371                                  r->px * (l->py - m->py) ) / 2.0;
 372
 373                 /* Size < 0 == backface */
 374                 //if (size < 0)
 375                 //      triangle->error *= -1;
 376                 triangle->error *= size;
 377         }
 378 }
 379
 380 /**
 381  * roam_triangle_split:
 382  * @triangle: the triangle
 383  * @sphere:   the sphere
 384  *
 385  * Split a triangle into two child triangles and update the sphere.
 386  */
 387 void roam_triangle_split(RoamTriangle *triangle, RoamSphere *sphere)
 388 {
 389         //g_message("roam_triangle_split: %p, e=%f\n", triangle, triangle->error);
 390
 391         sphere->polys += 2;
 392
 393         if (triangle != triangle->t.b->t.b)
 394                 roam_triangle_split(triangle->t.b, sphere);
 395         if (triangle != triangle->t.b->t.b)
 396                 g_assert_not_reached();
 397
 398         RoamTriangle *base = triangle->t.b;
 399
 400         /* Add new triangles */
 401         RoamPoint *mid = triangle->split;
 402         RoamTriangle *sl = triangle->kids[0] = roam_triangle_new(triangle->p.m, mid, triangle->p.l); // triangle Left
 403         RoamTriangle *sr = triangle->kids[1] = roam_triangle_new(triangle->p.r, mid, triangle->p.m); // triangle Right
 404         RoamTriangle *bl = base->kids[0] = roam_triangle_new(base->p.m, mid, base->p.l); // Base Left
 405         RoamTriangle *br = base->kids[1] = roam_triangle_new(base->p.r, mid, base->p.m); // Base Right
 406
 407         /*                triangle,l,  base,      r,  sphere */
 408         roam_triangle_add(sl, sr, triangle->t.l, br, sphere);
 409         roam_triangle_add(sr, bl, triangle->t.r, sl, sphere);
 410         roam_triangle_add(bl, br, base->t.l, sr, sphere);
 411         roam_triangle_add(br, sl, base->t.r, bl, sphere);
 412
 413         roam_triangle_sync_neighbors(sl, triangle, triangle->t.l);
 414         roam_triangle_sync_neighbors(sr, triangle, triangle->t.r);
 415         roam_triangle_sync_neighbors(bl, base, base->t.l);
 416         roam_triangle_sync_neighbors(br, base, base->t.r);
 417
 418         /* Remove old triangles */
 419         roam_triangle_remove(triangle, sphere);
 420         roam_triangle_remove(base, sphere);
 421
 422         /* Add/Remove diamonds */
 423         RoamDiamond *diamond = roam_diamond_new(triangle, base, sl, sr, bl, br);
 424         roam_diamond_update_errors(diamond, sphere);
 425         roam_diamond_add(diamond, sphere);
 426         roam_diamond_remove(triangle->parent, sphere);
 427         roam_diamond_remove(base->parent, sphere);
 428 }
 429
 430 /**
 431  * roam_triangle_draw:
 432  * @triangle: the triangle
 433  *
 434  * Draw the triangle. Use for debugging.
 435  */
 436 void roam_triangle_draw(RoamTriangle *triangle)
 437 {
 438         glBegin(GL_TRIANGLES);
 439         glNormal3dv(triangle->p.r->norm); glVertex3dv((double*)triangle->p.r);
 440         glNormal3dv(triangle->p.m->norm); glVertex3dv((double*)triangle->p.m);
 441         glNormal3dv(triangle->p.l->norm); glVertex3dv((double*)triangle->p.l);
 442         glEnd();
 443         return;
 444 }
 445
 446 /**
 447  * roam_triangle_draw_normal:
 448  * @triangle: the triangle
 449  *
 450  * Draw a normal vector for the triangle. Used while debugging.
 451  */
 452 void roam_triangle_draw_normal(RoamTriangle *triangle)
 453 {
 454         double center[] = {
 455                 (triangle->p.l->x + triangle->p.m->x + triangle->p.r->x)/3.0,
 456                 (triangle->p.l->y + triangle->p.m->y + triangle->p.r->y)/3.0,
 457                 (triangle->p.l->z + triangle->p.m->z + triangle->p.r->z)/3.0,
 458         };
 459         double end[] = {
 460                 center[0]+triangle->norm[0]*2000000,
 461                 center[1]+triangle->norm[1]*2000000,
 462                 center[2]+triangle->norm[2]*2000000,
 463         };
 464         glBegin(GL_LINES);
 465         glVertex3dv(center);
 466         glVertex3dv(end);
 467         glEnd();
 468 }
 469
 470 /***************
 471  * RoamDiamond *
 472  ***************/
 473 /**
 474  * roam_diamond_new:
 475  * @parent0: a parent triangle
 476  * @parent1: a parent triangle
 477  * @kid0:    a child triangle
 478  * @kid1:    a child triangle
 479  * @kid2:    a child triangle
 480  * @kid3:    a child triangle
 481  *
 482  * Create a diamond to store information about two split triangles.
 483  *
 484  * Returns: the new diamond
 485  */
 486 RoamDiamond *roam_diamond_new(
 487                 RoamTriangle *parent0, RoamTriangle *parent1,
 488                 RoamTriangle *kid0, RoamTriangle *kid1,
 489                 RoamTriangle *kid2, RoamTriangle *kid3)
 490 {
 491         RoamDiamond *diamond = g_new0(RoamDiamond, 1);
 492
 493         diamond->kids[0] = kid0;
 494         diamond->kids[1] = kid1;
 495         diamond->kids[2] = kid2;
 496         diamond->kids[3] = kid3;
 497
 498         kid0->parent = diamond;
 499         kid1->parent = diamond;
 500         kid2->parent = diamond;
 501         kid3->parent = diamond;
 502
 503         diamond->parents[0] = parent0;
 504         diamond->parents[1] = parent1;
 505
 506         return diamond;
 507 }
 508
 509 /**
 510  * roam_diamond_add:
 511  * @diamond: the diamond
 512  * @sphere:  the sphere to add the diamond to
 513  *
 514  * Add a diamond into the sphere's pool of diamonds. It will be check for
 515  * possible merges.
 516  */
 517 void roam_diamond_add(RoamDiamond *diamond, RoamSphere *sphere)
 518 {
 519         diamond->active = TRUE;
 520         diamond->error  = MAX(diamond->parents[0]->error, diamond->parents[1]->error);
 521         diamond->handle = g_pqueue_push(sphere->diamonds, diamond);
 522 }
 523
 524 /**
 525  * roam_diamond_remove:
 526  * @diamond: the diamond
 527  * @sphere:  the sphere to remove the diamond from
 528  *
 529  * Remove a diamond from the sphere's pool of diamonds.
 530  */
 531 void roam_diamond_remove(RoamDiamond *diamond, RoamSphere *sphere)
 532 {
 533         if (diamond && diamond->active) {
 534                 diamond->active = FALSE;
 535                 g_pqueue_remove(sphere->diamonds, diamond->handle);
 536         }
 537 }
 538
 539 /**
 540  * roam_diamond_merge:
 541  * @diamond: the diamond
 542  * @sphere:  the sphere
 543  *
 544  * "Merge" a diamond back into two parent triangles. The original two triangles
 545  * are added back into the sphere and the four child triangles as well as the
 546  * diamond are removed.
 547  */
 548 void roam_diamond_merge(RoamDiamond *diamond, RoamSphere *sphere)
 549 {
 550         //g_message("roam_diamond_merge: %p, e=%f\n", diamond, diamond->error);
 551
 552         sphere->polys -= 2;
 553
 554         /* TODO: pick the best split */
 555         RoamTriangle **kids = diamond->kids;
 556
 557         /* Create triangles */
 558         RoamTriangle *triangle  = diamond->parents[0];
 559         RoamTriangle *base = diamond->parents[1];
 560
 561         roam_triangle_add(triangle,  kids[0]->t.b, base, kids[1]->t.b, sphere);
 562         roam_triangle_add(base, kids[2]->t.b, triangle,  kids[3]->t.b, sphere);
 563
 564         roam_triangle_sync_neighbors(triangle,  kids[0], kids[0]->t.b);
 565         roam_triangle_sync_neighbors(triangle,  kids[1], kids[1]->t.b);
 566         roam_triangle_sync_neighbors(base, kids[2], kids[2]->t.b);
 567         roam_triangle_sync_neighbors(base, kids[3], kids[3]->t.b);
 568
 569         /* Remove triangles */
 570         roam_triangle_remove(kids[0], sphere);
 571         roam_triangle_remove(kids[1], sphere);
 572         roam_triangle_remove(kids[2], sphere);
 573         roam_triangle_remove(kids[3], sphere);
 574
 575         /* Clear kids */
 576         triangle->kids[0]  = triangle->kids[1]  = NULL;
 577         base->kids[0] = base->kids[1] = NULL;
 578
 579         /* Add/Remove triangles */
 580         if (triangle->t.l->t.l == triangle->t.r->t.r &&
 581             triangle->t.l->t.l != triangle && triangle->parent) {
 582                 roam_diamond_update_errors(triangle->parent, sphere);
 583                 roam_diamond_add(triangle->parent, sphere);
 584         }
 585
 586         if (base->t.l->t.l == base->t.r->t.r &&
 587             base->t.l->t.l != base && base->parent) {
 588                 roam_diamond_update_errors(base->parent, sphere);
 589                 roam_diamond_add(base->parent, sphere);
 590         }
 591
 592         /* Remove and free diamond and child triangles */
 593         roam_diamond_remove(diamond, sphere);
 594         g_assert(diamond->kids[0]->p.m == diamond->kids[1]->p.m &&
 595                  diamond->kids[1]->p.m == diamond->kids[2]->p.m &&
 596                  diamond->kids[2]->p.m == diamond->kids[3]->p.m);
 597         g_assert(diamond->kids[0]->p.m->tris == 0);
 598         roam_triangle_free(diamond->kids[0]);
 599         roam_triangle_free(diamond->kids[1]);
 600         roam_triangle_free(diamond->kids[2]);
 601         roam_triangle_free(diamond->kids[3]);
 602         g_free(diamond);
 603 }
 604
 605 /**
 606  * roam_diamond_update_errors:
 607  * @diamond: the diamond
 608  * @sphere:  the sphere to use when updating errors
 609  *
 610  * Update the error value associated with a diamond. Called when the view
 611  * changes.
 612  */
 613 void roam_diamond_update_errors(RoamDiamond *diamond, RoamSphere *sphere)
 614 {
 615         roam_triangle_update_errors(diamond->parents[0], sphere);
 616         roam_triangle_update_errors(diamond->parents[1], sphere);
 617         diamond->error = MAX(diamond->parents[0]->error, diamond->parents[1]->error);
 618 }
 619
 620 /**************
 621  * RoamSphere *
 622  **************/
 623 /**
 624  * roam_sphere_new:
 625  *
 626  * Create a new sphere
 627  *
 628  * Returns: the sphere
 629  */
 630 RoamSphere *roam_sphere_new()
 631 {
 632         RoamSphere *sphere = g_new0(RoamSphere, 1);
 633         sphere->polys       = 8;
 634         sphere->triangles   = g_pqueue_new((GCompareDataFunc)tri_cmp, NULL);
 635         sphere->diamonds    = g_pqueue_new((GCompareDataFunc)dia_cmp, NULL);
 636
 637         RoamPoint *vertexes[] = {
 638                 roam_point_new( 90,   0,  0), // 0 (North)
 639                 roam_point_new(-90,   0,  0), // 1 (South)
 640                 roam_point_new(  0,   0,  0), // 2 (Europe/Africa)
 641                 roam_point_new(  0,  90,  0), // 3 (Asia,East)
 642                 roam_point_new(  0, 180,  0), // 4 (Pacific)
 643                 roam_point_new(  0, -90,  0), // 5 (Americas,West)
 644         };
 645         int _triangles[][2][3] = {
 646                 /*lv mv rv   ln, bn, rn */
 647                 {{2,0,3}, {3, 4, 1}}, // 0
 648                 {{3,0,4}, {0, 5, 2}}, // 1
 649                 {{4,0,5}, {1, 6, 3}}, // 2
 650                 {{5,0,2}, {2, 7, 0}}, // 3
 651                 {{3,1,2}, {5, 0, 7}}, // 4
 652                 {{4,1,3}, {6, 1, 4}}, // 5
 653                 {{5,1,4}, {7, 2, 5}}, // 6
 654                 {{2,1,5}, {4, 3, 6}}, // 7
 655         };
 656
 657         for (int i = 0; i < 6; i++)
 658                 roam_point_update_height(vertexes[i]);
 659         for (int i = 0; i < 8; i++)
 660                 sphere->roots[i] = roam_triangle_new(
 661                         vertexes[_triangles[i][0][0]],
 662                         vertexes[_triangles[i][0][1]],
 663                         vertexes[_triangles[i][0][2]]);
 664         for (int i = 0; i < 8; i++)
 665                 roam_triangle_add(sphere->roots[i],
 666                         sphere->roots[_triangles[i][1][0]],
 667                         sphere->roots[_triangles[i][1][1]],
 668                         sphere->roots[_triangles[i][1][2]],
 669                         sphere);
 670         for (int i = 0; i < 8; i++)
 671                 g_debug("RoamSphere: new - %p edge=%f,%f,%f,%f", sphere->roots[i],
 672                                 sphere->roots[i]->edge.n,
 673                                 sphere->roots[i]->edge.s,
 674                                 sphere->roots[i]->edge.e,
 675                                 sphere->roots[i]->edge.w);
 676
 677         return sphere;
 678 }
 679
 680 /**
 681  * roam_sphere_update_view
 682  * @sphere: the sphere
 683  *
 684  * Recreate the sphere's view matrices based on the current OpenGL state.
 685  */
 686 void roam_sphere_update_view(RoamSphere *sphere)
 687 {
 688         if (!sphere->view)
 689                 sphere->view = g_new0(RoamView, 1);
 690         glGetDoublev (GL_MODELVIEW_MATRIX,  sphere->view->model);
 691         glGetDoublev (GL_PROJECTION_MATRIX, sphere->view->proj);
 692         glGetIntegerv(GL_VIEWPORT,          sphere->view->view);
 693         sphere->view->version++;
 694 }
 695
 696 /**
 697  * roam_sphere_update_errors
 698  * @sphere: the sphere
 699  *
 700  * Update triangle and diamond errors in the sphere.
 701  */
 702 void roam_sphere_update_errors(RoamSphere *sphere)
 703 {
 704         g_debug("RoamSphere: update_errors - polys=%d", sphere->polys);
 705         GPtrArray *tris = g_pqueue_get_array(sphere->triangles);
 706         GPtrArray *dias = g_pqueue_get_array(sphere->diamonds);
 707
 708         roam_sphere_update_view(sphere);
 709
 710         for (int i = 0; i < tris->len; i++) {
 711                 RoamTriangle *triangle = tris->pdata[i];
 712                 roam_triangle_update_errors(triangle, sphere);
 713                 g_pqueue_priority_changed(sphere->triangles, triangle->handle);
 714         }
 715
 716         for (int i = 0; i < dias->len; i++) {
 717                 RoamDiamond *diamond = dias->pdata[i];
 718                 roam_diamond_update_errors(diamond, sphere);
 719                 g_pqueue_priority_changed(sphere->diamonds, diamond->handle);
 720         }
 721
 722         g_ptr_array_free(tris, TRUE);
 723         g_ptr_array_free(dias, TRUE);
 724 }
 725
 726 /**
 727  * roam_sphere_split_one
 728  * @sphere: the sphere
 729  *
 730  * Split the triangle with the greatest error.
 731  */
 732 void roam_sphere_split_one(RoamSphere *sphere)
 733 {
 734         RoamTriangle *to_split = g_pqueue_peek(sphere->triangles);
 735         if (!to_split) return;
 736         roam_triangle_split(to_split, sphere);
 737 }
 738
 739 /**
 740  * roam_sphere_merge_one
 741  * @sphere: the sphere
 742  *
 743  * Merge the diamond with the lowest error.
 744  */
 745 void roam_sphere_merge_one(RoamSphere *sphere)
 746 {
 747         RoamDiamond *to_merge = g_pqueue_peek(sphere->diamonds);
 748         if (!to_merge) return;
 749         roam_diamond_merge(to_merge, sphere);
 750 }
 751
 752 /**
 753  * roam_sphere_split_merge
 754  * @sphere: the sphere
 755  *
 756  * Perform a predetermined number split-merge iterations.
 757  *
 758  * Returns: the number splits and merges done
 759  */
 760 gint roam_sphere_split_merge(RoamSphere *sphere)
 761 {
 762         gint iters = 0, max_iters = 500;
 763         //gint target = 4000;
 764         gint target = 2000;
 765         //gint target = 500;
 766
 767         if (!sphere->view)
 768                 return 0;
 769
 770         if (target - sphere->polys > 100) {
 771                 //g_debug("RoamSphere: split_merge - Splitting %d - %d > 100", target, sphere->polys);
 772                 while (sphere->polys < target && iters++ < max_iters)
 773                         roam_sphere_split_one(sphere);
 774         }
 775
 776         if (sphere->polys - target > 100) {
 777                 //g_debug("RoamSphere: split_merge - Merging %d - %d > 100", sphere->polys, target);
 778                 while (sphere->polys > target && iters++ < max_iters)
 779                         roam_sphere_merge_one(sphere);
 780         }
 781
 782         while (((RoamTriangle*)g_pqueue_peek(sphere->triangles))->error >
 783                ((RoamDiamond *)g_pqueue_peek(sphere->diamonds ))->error &&
 784                iters++ < max_iters) {
 785                 //g_debug("RoamSphere: split_merge - Fixing 1 %f > %f && %d < %d",
 786                 //              ((RoamTriangle*)g_pqueue_peek(sphere->triangles))->error,
 787                 //              ((RoamDiamond *)g_pqueue_peek(sphere->diamonds ))->error,
 788                 //              iters-1, max_iters);
 789                 roam_sphere_merge_one(sphere);
 790                 roam_sphere_split_one(sphere);
 791         }
 792
 793         return iters;
 794 }
 795
 796 /**
 797  * roam_sphere_draw:
 798  * @sphere: the sphere
 799  *
 800  * Draw the sphere. Use for debugging.
 801  */
 802 void roam_sphere_draw(RoamSphere *sphere)
 803 {
 804         g_debug("RoamSphere: draw");
 805         g_pqueue_foreach(sphere->triangles, (GFunc)roam_triangle_draw, NULL);
 806 }
 807
 808 /**
 809  * roam_sphere_draw_normals
 810  * @sphere: the sphere
 811  *
 812  * Draw all the surface normal vectors for the sphere. Used while debugging.
 813  */
 814 void roam_sphere_draw_normals(RoamSphere *sphere)
 815 {
 816         g_debug("RoamSphere: draw_normal");
 817         g_pqueue_foreach(sphere->triangles, (GFunc)roam_triangle_draw_normal, NULL);
 818 }
 819
 820 static GList *_roam_sphere_get_leaves(RoamTriangle *triangle, GList *list, gboolean all)
 821 {
 822         if (triangle->kids[0] && triangle->kids[1]) {
 823                 if (all) list = g_list_prepend(list, triangle);
 824                 list = _roam_sphere_get_leaves(triangle->kids[0], list, all);
 825                 list = _roam_sphere_get_leaves(triangle->kids[1], list, all);
 826                 return list;
 827         } else {
 828                 return g_list_prepend(list, triangle);
 829         }
 830 }
 831
 832 static GList *_roam_sphere_get_intersect_rec(RoamTriangle *triangle, GList *list,
 833                 gboolean all, gdouble n, gdouble s, gdouble e, gdouble w)
 834 {
 835         gdouble tn = triangle->edge.n;
 836         gdouble ts = triangle->edge.s;
 837         gdouble te = triangle->edge.e;
 838         gdouble tw = triangle->edge.w;
 839
 840         gboolean debug = FALSE  &&
 841                 n==90 && s==45 && e==-90 && w==-180 &&
 842                 ts > 44 && ts < 46;
 843
 844         if (debug)
 845                 g_message("t=%p: %f < %f || %f > %f || %f < %f || %f > %f",
 846                             triangle, tn,   s,   ts,   n,   te,   w,   tw,   e);
 847         if (tn <= s || ts >= n || te <= w || tw >= e) {
 848                 /* No intersect */
 849                 if (debug) g_message("no intersect");
 850                 return list;
 851         } else if (tn <= n && ts >= s && te <= e && tw >= w) {
 852                 /* Triangle is completely contained */
 853                 if (debug) g_message("contained");
 854                 if (all) list = g_list_prepend(list, triangle);
 855                 return _roam_sphere_get_leaves(triangle, list, all);
 856         } else if (triangle->kids[0] && triangle->kids[1]) {
 857                 /* Paritial intersect with children */
 858                 if (debug) g_message("edge w/ child");
 859                 if (all) list = g_list_prepend(list, triangle);
 860                 list = _roam_sphere_get_intersect_rec(triangle->kids[0], list, all, n, s, e, w);
 861                 list = _roam_sphere_get_intersect_rec(triangle->kids[1], list, all, n, s, e, w);
 862                 return list;
 863         } else {
 864                 /* This triangle is an edge case */
 865                 if (debug) g_message("edge");
 866                 return g_list_prepend(list, triangle);
 867         }
 868 }
 869
 870 /**
 871  * roam_sphere_get_intersect
 872  * @sphere: the sphere
 873  * @all: TRUE if non-leaf triangle should be returned as well
 874  * @n: the northern edge
 875  * @s: the southern edge
 876  * @e: the eastern edge
 877  * @w: the western edge
 878  *
 879  * Lookup triangles withing the sphere that intersect a given lat-lon box.
 880  *
 881  * Returns: the list of intersecting triangles.
 882  */
 883 /* Warning: This grabs pointers to triangles which can be changed by other
 884  * calls, e.g. split_merge. If you use this, you need to do some locking to
 885  * prevent the returned list from becomming stale. */
 886 GList *roam_sphere_get_intersect(RoamSphere *sphere, gboolean all,
 887                 gdouble n, gdouble s, gdouble e, gdouble w)
 888 {
 889         /* I think this is correct..
 890          * i_cost = cost for triangle-rectagnle intersect test
 891          * time = n_tiles * 2*tris_per_tile * i_cost
 892          * time = 30      * 2*333           * i_cost = 20000 * i_cost */
 893         GList *list = NULL;
 894         for (int i = 0; i < G_N_ELEMENTS(sphere->roots); i++)
 895                 list = _roam_sphere_get_intersect_rec(sphere->roots[i],
 896                                 list, all, n, s, e, w);
 897         return list;
 898 }
 899
 900 static void roam_sphere_free_tri(RoamTriangle *triangle)
 901 {
 902         if (--triangle->p.l->tris == 0) g_free(triangle->p.l);
 903         if (--triangle->p.m->tris == 0) g_free(triangle->p.m);
 904         if (--triangle->p.r->tris == 0) g_free(triangle->p.r);
 905         roam_triangle_free(triangle);
 906 }
 907
 908 /**
 909  * roam_sphere_free
 910  * @sphere: the sphere
 911  *
 912  * Free data associated with a sphere
 913  */
 914 void roam_sphere_free(RoamSphere *sphere)
 915 {
 916         g_debug("RoamSphere: free");
 917         /* Slow method, but it should work */
 918         while (sphere->polys > 8)
 919                 roam_sphere_merge_one(sphere);
 920         /* TODO: free points */
 921         g_pqueue_foreach(sphere->triangles, (GFunc)roam_sphere_free_tri, NULL);
 922         g_pqueue_free(sphere->triangles);
 923         g_pqueue_free(sphere->diamonds);
 924         g_free(sphere->view);
 925         g_free(sphere);
 926 }