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

   1 /*
   2  * Copyright (C) 2009-2011 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 #GritsOpenGL
  25  * when drawing surface textures for GritsTiles.
  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
  35 #include "gtkgl.h"
  36 #include "gpqueue.h"
  37 #include "grits-util.h"
  38 #include "roam.h"
  39
  40 /*
  41  * TODO:
  42  *   - Optimize for memory consumption
  43  *   - Profile for computation speed
  44  *   - Target polygon count/detail
  45  */
  46
  47 /* For GPQueue comparators */
  48 static gint tri_cmp(RoamTriangle *a, RoamTriangle *b, gpointer data)
  49 {
  50         if      (a->error < b->error) return  1;
  51         else if (a->error > b->error) return -1;
  52         else                          return  0;
  53 }
  54 static gint dia_cmp(RoamDiamond *a, RoamDiamond *b, gpointer data)
  55 {
  56         if      (a->error < b->error) return -1;
  57         else if (a->error > b->error) return  1;
  58         else                          return  0;
  59 }
  60
  61
  62 /*************
  63  * RoamPoint *
  64  *************/
  65 /**
  66  * roam_point_new:
  67  * @lat:  the latitude for the point
  68  * @lon:  the longitude for the point
  69  * @elev: the elevation for the point
  70  *
  71  * Create a new point at the given locaiton
  72  *
  73  * Returns: the new point
  74  */
  75 RoamPoint *roam_point_new(gdouble lat, gdouble lon, gdouble elev)
  76 {
  77         RoamPoint *point = g_new0(RoamPoint, 1);
  78         point->lat  = lat;
  79         point->lon  = lon;
  80         point->elev = elev;
  81         /* For get_intersect */
  82         lle2xyz(lat, lon, elev, &point->x, &point->y, &point->z);
  83         return point;
  84 }
  85
  86 /**
  87  * roam_point_add_triangle:
  88  * @point:    the point
  89  * @triangle: the to add
  90  *
  91  * Associating a triangle with a point and update it's vertex normal.
  92  */
  93 void roam_point_add_triangle(RoamPoint *point, RoamTriangle *triangle)
  94 {
  95         for (int i = 0; i < 3; i++) {
  96                 point->norm[i] *= point->tris;
  97                 point->norm[i] += triangle->norm[i];
  98         }
  99         point->tris++;
 100         for (int i = 0; i < 3; i++)
 101                 point->norm[i] /= point->tris;
 102 }
 103
 104 /**
 105  * roam_point_remove_triangle:
 106  * @point:    the point
 107  * @triangle: the to add
 108  *
 109  * Un-associating a triangle with a point and update it's vertex normal.
 110  */
 111 void roam_point_remove_triangle(RoamPoint *point, RoamTriangle *triangle)
 112 {
 113         for (int i = 0; i < 3; i++) {
 114                 point->norm[i] *= point->tris;
 115                 point->norm[i] -= triangle->norm[i];
 116         }
 117         point->tris--;
 118         if (point->tris)
 119                 for (int i = 0; i < 3; i++)
 120                         point->norm[i] /= point->tris;
 121 }
 122
 123 /**
 124  * roam_point_update_height:
 125  * @point: the point
 126  *
 127  * Update the height (elevation) of a point based on the current height function
 128  */
 129 void roam_point_update_height(RoamPoint *point)
 130 {
 131         if (point->height_func) {
 132                 gdouble elev = point->height_func(
 133                                 point->lat, point->lon, point->height_data);
 134                 lle2xyz(point->lat, point->lon, elev,
 135                                 &point->x, &point->y, &point->z);
 136         }
 137 }
 138
 139 /**
 140  * roam_point_update_projection:
 141  * @point: the point
 142  * @view:  the view to use when projecting the point
 143  *
 144  * Updated the screen-space projection of a point.
 145  */
 146 void roam_point_update_projection(RoamPoint *point, RoamView *view)
 147 {
 148         static int count   = 0;
 149         static int version = 0;
 150         if (version != view->version) {
 151                 g_debug("RoamPoint: Projected %d points", count);
 152                 count   = 0;
 153                 version = view->version;
 154         }
 155
 156         if (point->pversion != view->version) {
 157                 /* Cache projection */
 158                 gluProject(point->x, point->y, point->z,
 159                         view->model, view->proj, view->view,
 160                         &point->px, &point->py, &point->pz);
 161                 point->pversion = view->version;
 162                 count++;
 163         }
 164 }
 165
 166 /****************
 167  * RoamTriangle *
 168  ****************/
 169 /**
 170  * roam_triangle_new:
 171  * @l: the left point
 172  * @m: the middle point
 173  * @r: the right point
 174  *
 175  * Create a new triangle consisting of three points.
 176  *
 177  * Returns: the new triangle
 178  */
 179 RoamTriangle *roam_triangle_new(RoamPoint *l, RoamPoint *m, RoamPoint *r,
 180                 RoamDiamond *parent)
 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->parent = parent;
 189         triangle->split  = roam_point_new(
 190                 (l->lat + r->lat)/2,
 191                 (ABS(l->lat) == 90 ? r->lon :
 192                  ABS(r->lat) == 90 ? l->lon :
 193                  lon_avg(l->lon, r->lon)),
 194                 (l->elev + r->elev)/2);
 195         /* TODO: Move this back to sphere, or actually use the nesting */
 196         triangle->split->height_func = m->height_func;
 197         triangle->split->height_data = m->height_data;
 198         roam_point_update_height(triangle->split);
 199         //if ((float)triangle->split->lat > 44 && (float)triangle->split->lat < 46)
 200         //      g_debug("RoamTriangle: new - (l,m,r,split).lats = %7.2f %7.2f %7.2f %7.2f",
 201         //                      l->lat, m->lat, r->lat, triangle->split->lat);
 202         //if ((float)l->lat == (float)r->lat &&
 203         //    (float)triangle->split->lat != (float)l->lat)
 204         //      g_warning("RoamTriangle: new - split.lat=%f != (l=r).lat=%f",
 205         //              triangle->split->lat, l->lat);
 206
 207         /* Update normal */
 208         crossd3((gdouble*)triangle->p.l,
 209                 (gdouble*)triangle->p.m,
 210                 (gdouble*)triangle->p.r, triangle->norm);
 211         normd(triangle->norm);
 212
 213         /* Store bounding box, for get_intersect */
 214         RoamPoint *p[] = {l,m,r};
 215         triangle->edge.n =  -90; triangle->edge.s =  90;
 216         triangle->edge.e = -180; triangle->edge.w = 180;
 217         gboolean maxed = FALSE;
 218         for (int i = 0; i < G_N_ELEMENTS(p); i++) {
 219                 triangle->edge.n = MAX(triangle->edge.n, p[i]->lat);
 220                 triangle->edge.s = MIN(triangle->edge.s, p[i]->lat);
 221                 if (p[i]->lat == 90 || p[i]->lat == -90)
 222                         continue;
 223                 if (p[i]->lon == 180) {
 224                         maxed = TRUE;
 225                         continue;
 226                 }
 227                 triangle->edge.e = MAX(triangle->edge.e, p[i]->lon);
 228                 triangle->edge.w = MIN(triangle->edge.w, p[i]->lon);
 229         }
 230         if (maxed) {
 231                 if (triangle->edge.e < 0)
 232                         triangle->edge.w = -180;
 233                 else
 234                         triangle->edge.e =  180;
 235         }
 236
 237         //g_message("roam_triangle_new: %p", triangle);
 238         return triangle;
 239 }
 240
 241 /**
 242  * roam_triangle_free:
 243  * @triangle: the triangle
 244  *
 245  * Free data associated with a triangle
 246  */
 247 void roam_triangle_free(RoamTriangle *triangle)
 248 {
 249         g_free(triangle->split);
 250         g_free(triangle);
 251 }
 252
 253 /**
 254  * roam_triangle_add:
 255  * @triangle: the triangle
 256  * @left:     the left neighbor
 257  * @base:     the base neighbor
 258  * @right:    the right neighbor
 259  * @sphere:   the sphere to add the triangle to
 260  *
 261  * Add a triangle into the sphere's mesh using the given neighbors.
 262  */
 263 void roam_triangle_add(RoamTriangle *triangle,
 264                 RoamTriangle *left, RoamTriangle *base, RoamTriangle *right,
 265                 RoamSphere *sphere)
 266 {
 267         triangle->t.l = left;
 268         triangle->t.b = base;
 269         triangle->t.r = right;
 270
 271         roam_point_add_triangle(triangle->p.l, triangle);
 272         roam_point_add_triangle(triangle->p.m, triangle);
 273         roam_point_add_triangle(triangle->p.r, triangle);
 274
 275         if (sphere->view)
 276                 roam_triangle_update_errors(triangle, sphere);
 277
 278         triangle->handle = g_pqueue_push(sphere->triangles, triangle);
 279 }
 280
 281 /**
 282  * roam_triangle_remove:
 283  * @triangle: the triangle
 284  * @sphere:   the sphere to remove the triangle from
 285  *
 286  * Remove a triangle from a sphere's mesh.
 287  */
 288 void roam_triangle_remove(RoamTriangle *triangle, RoamSphere *sphere)
 289 {
 290         /* Update vertex normals */
 291         roam_point_remove_triangle(triangle->p.l, triangle);
 292         roam_point_remove_triangle(triangle->p.m, triangle);
 293         roam_point_remove_triangle(triangle->p.r, triangle);
 294
 295         g_pqueue_remove(sphere->triangles, triangle->handle);
 296 }
 297
 298 /* (neight->t.? == old) = new */
 299 static void roam_triangle_sync_neighbors(RoamTriangle *neigh, RoamTriangle *old, RoamTriangle *new)
 300 {
 301         if      (neigh->t.l == old) neigh->t.l = new;
 302         else if (neigh->t.b == old) neigh->t.b = new;
 303         else if (neigh->t.r == old) neigh->t.r = new;
 304 }
 305
 306 static gboolean roam_triangle_visible(RoamTriangle *triangle, RoamSphere *sphere)
 307 {
 308         RoamPoint *l = triangle->p.l;
 309         RoamPoint *m = triangle->p.m;
 310         RoamPoint *r = triangle->p.r;
 311         gdouble min_x = MIN(MIN(l->px, m->px), r->px);
 312         gdouble max_x = MAX(MAX(l->px, m->px), r->px);
 313         gdouble min_y = MIN(MIN(l->py, m->py), r->py);
 314         gdouble max_y = MAX(MAX(l->py, m->py), r->py);
 315         gint *view = sphere->view->view;
 316         return !(max_x < view[0] || min_x > view[2] ||
 317                  max_y < view[1] || min_y > view[3]) &&
 318                  l->pz > 0 && m->pz > 0 && r->pz > 0 &&
 319                  l->pz < 1 && m->pz < 1 && r->pz < 1;
 320 }
 321
 322 static gboolean roam_triangle_backface(RoamTriangle *triangle, RoamSphere *sphere)
 323 {
 324         RoamPoint *l = triangle->p.l;
 325         RoamPoint *m = triangle->p.m;
 326         RoamPoint *r = triangle->p.r;
 327         roam_point_update_projection(l, sphere->view);
 328         roam_point_update_projection(m, sphere->view);
 329         roam_point_update_projection(r, sphere->view);
 330         double size = -( l->px * (m->py - r->py) +
 331                          m->px * (r->py - l->py) +
 332                          r->px * (l->py - m->py) ) / 2.0;
 333         return size < 0;
 334 }
 335
 336 /**
 337  * roam_triangle_update_errors:
 338  * @triangle: the triangle
 339  * @sphere:   the sphere to use when updating errors
 340  *
 341  * Update the error value associated with a triangle. Called when the view
 342  * changes.
 343  */
 344 void roam_triangle_update_errors(RoamTriangle *triangle, RoamSphere *sphere)
 345 {
 346         /* Update points */
 347         roam_point_update_projection(triangle->p.l, sphere->view);
 348         roam_point_update_projection(triangle->p.m, sphere->view);
 349         roam_point_update_projection(triangle->p.r, sphere->view);
 350
 351         if (!roam_triangle_visible(triangle, sphere)) {
 352                 triangle->error = -1;
 353         } else {
 354                 roam_point_update_projection(triangle->split, sphere->view);
 355                 RoamPoint *l     = triangle->p.l;
 356                 RoamPoint *m     = triangle->p.m;
 357                 RoamPoint *r     = triangle->p.r;
 358                 RoamPoint *split = triangle->split;
 359
 360                 /*               l-r midpoint        projected l-r midpoint */
 361                 gdouble pxdist = (l->px + r->px)/2 - split->px;
 362                 gdouble pydist = (l->py + r->py)/2 - split->py;
 363
 364                 triangle->error = sqrt(pxdist*pxdist + pydist*pydist);
 365
 366                 /* Multiply by size of triangle */
 367                 double size = -( l->px * (m->py - r->py) +
 368                                  m->px * (r->py - l->py) +
 369                                  r->px * (l->py - m->py) ) / 2.0;
 370
 371                 /* Size < 0 == backface */
 372                 triangle->error *= size;
 373
 374                 /* Give some preference to "edge" faces */
 375                 if (roam_triangle_backface(triangle->t.l, sphere) ||
 376                     roam_triangle_backface(triangle->t.b, sphere) ||
 377                     roam_triangle_backface(triangle->t.r, sphere))
 378                         triangle->error *= 50;
 379         }
 380 }
 381
 382 /**
 383  * roam_triangle_split:
 384  * @triangle: the triangle
 385  * @sphere:   the sphere
 386  *
 387  * Split a triangle into two child triangles and update the sphere.
 388  * triangle
 389  */
 390 void roam_triangle_split(RoamTriangle *triangle, RoamSphere *sphere)
 391 {
 392         //g_message("roam_triangle_split: %p, e=%f\n", triangle, triangle->error);
 393
 394         sphere->polys += 2;
 395
 396         if (triangle != triangle->t.b->t.b)
 397                 roam_triangle_split(triangle->t.b, sphere);
 398         if (triangle != triangle->t.b->t.b)
 399                 g_assert_not_reached();
 400
 401         RoamTriangle *s = triangle;      // Self
 402         RoamTriangle *b = triangle->t.b; // Base
 403
 404         RoamDiamond *dia = roam_diamond_new(s, b);
 405
 406         /* Add new triangles */
 407         RoamPoint *mid = triangle->split;
 408         RoamTriangle *sl = s->kids[0] = roam_triangle_new(s->p.m, mid, s->p.l, dia); // Self Left
 409         RoamTriangle *sr = s->kids[1] = roam_triangle_new(s->p.r, mid, s->p.m, dia); // Self Right
 410         RoamTriangle *bl = b->kids[0] = roam_triangle_new(b->p.m, mid, b->p.l, dia); // Base Left
 411         RoamTriangle *br = b->kids[1] = roam_triangle_new(b->p.r, mid, b->p.m, dia); // Base Right
 412
 413         /*                triangle,l,  base,      r,  sphere */
 414         roam_triangle_add(sl, sr, s->t.l, br, sphere);
 415         roam_triangle_add(sr, bl, s->t.r, sl, sphere);
 416         roam_triangle_add(bl, br, b->t.l, sr, sphere);
 417         roam_triangle_add(br, sl, b->t.r, bl, sphere);
 418
 419         roam_triangle_sync_neighbors(s->t.l, s, sl);
 420         roam_triangle_sync_neighbors(s->t.r, s, sr);
 421         roam_triangle_sync_neighbors(b->t.l, b, bl);
 422         roam_triangle_sync_neighbors(b->t.r, b, br);
 423
 424         /* Remove old triangles */
 425         roam_triangle_remove(s, sphere);
 426         roam_triangle_remove(b, sphere);
 427
 428         /* Add/Remove diamonds */
 429         roam_diamond_update_errors(dia, sphere);
 430         roam_diamond_add(dia, sphere);
 431         roam_diamond_remove(s->parent, sphere);
 432         roam_diamond_remove(b->parent, sphere);
 433 }
 434
 435 /**
 436  * roam_triangle_draw:
 437  * @triangle: the triangle
 438  *
 439  * Draw the triangle. Use for debugging.
 440  */
 441 void roam_triangle_draw(RoamTriangle *triangle)
 442 {
 443         glBegin(GL_TRIANGLES);
 444         glNormal3dv(triangle->p.r->norm); glVertex3dv((double*)triangle->p.r);
 445         glNormal3dv(triangle->p.m->norm); glVertex3dv((double*)triangle->p.m);
 446         glNormal3dv(triangle->p.l->norm); glVertex3dv((double*)triangle->p.l);
 447         glEnd();
 448         return;
 449 }
 450
 451 /**
 452  * roam_triangle_draw_normal:
 453  * @triangle: the triangle
 454  *
 455  * Draw a normal vector for the triangle. Used while debugging.
 456  */
 457 void roam_triangle_draw_normal(RoamTriangle *triangle)
 458 {
 459         double center[] = {
 460                 (triangle->p.l->x + triangle->p.m->x + triangle->p.r->x)/3.0,
 461                 (triangle->p.l->y + triangle->p.m->y + triangle->p.r->y)/3.0,
 462                 (triangle->p.l->z + triangle->p.m->z + triangle->p.r->z)/3.0,
 463         };
 464         double end[] = {
 465                 center[0]+triangle->norm[0]*2000000,
 466                 center[1]+triangle->norm[1]*2000000,
 467                 center[2]+triangle->norm[2]*2000000,
 468         };
 469         glBegin(GL_LINES);
 470         glVertex3dv(center);
 471         glVertex3dv(end);
 472         glEnd();
 473 }
 474
 475 /***************
 476  * RoamDiamond *
 477  ***************/
 478 /**
 479  * roam_diamond_new:
 480  * @parent0: a parent triangle
 481  * @parent1: a parent triangle
 482  * @kid0:    a child triangle
 483  * @kid1:    a child triangle
 484  * @kid2:    a child triangle
 485  * @kid3:    a child triangle
 486  *
 487  * Create a diamond to store information about two split triangles.
 488  *
 489  * Returns: the new diamond
 490  */
 491 RoamDiamond *roam_diamond_new(RoamTriangle *parent0, RoamTriangle *parent1)
 492 {
 493         RoamDiamond *diamond = g_new0(RoamDiamond, 1);
 494         diamond->parents[0] = parent0;
 495         diamond->parents[1] = parent1;
 496         return diamond;
 497 }
 498
 499 /**
 500  * roam_diamond_add:
 501  * @diamond: the diamond
 502  * @sphere:  the sphere to add the diamond to
 503  *
 504  * Add a diamond into the sphere's pool of diamonds. It will be check for
 505  * possible merges.
 506  */
 507 void roam_diamond_add(RoamDiamond *diamond, RoamSphere *sphere)
 508 {
 509         diamond->active = TRUE;
 510         diamond->error  = MAX(diamond->parents[0]->error, diamond->parents[1]->error);
 511         diamond->handle = g_pqueue_push(sphere->diamonds, diamond);
 512 }
 513
 514 /**
 515  * roam_diamond_remove:
 516  * @diamond: the diamond
 517  * @sphere:  the sphere to remove the diamond from
 518  *
 519  * Remove a diamond from the sphere's pool of diamonds.
 520  */
 521 void roam_diamond_remove(RoamDiamond *diamond, RoamSphere *sphere)
 522 {
 523         if (diamond && diamond->active) {
 524                 diamond->active = FALSE;
 525                 g_pqueue_remove(sphere->diamonds, diamond->handle);
 526         }
 527 }
 528
 529 /**
 530  * roam_diamond_merge:
 531  * @diamond: the diamond
 532  * @sphere:  the sphere
 533  *
 534  * "Merge" a diamond back into two parent triangles. The original two triangles
 535  * are added back into the sphere and the four child triangles as well as the
 536  * diamond are removed.
 537  */
 538 void roam_diamond_merge(RoamDiamond *diamond, RoamSphere *sphere)
 539 {
 540         //g_message("roam_diamond_merge: %p, e=%f\n", diamond, diamond->error);
 541
 542         /* TODO: pick the best split */
 543         sphere->polys -= 2;
 544
 545         /* Use nicer temp names */
 546         RoamTriangle *s = diamond->parents[0]; // Self
 547         RoamTriangle *b = diamond->parents[1]; // Base
 548
 549         RoamTriangle *sl = s->kids[0];
 550         RoamTriangle *sr = s->kids[1];
 551         RoamTriangle *bl = b->kids[0];
 552         RoamTriangle *br = b->kids[1];
 553
 554         s->kids[0] = s->kids[1] = NULL;
 555         b->kids[0] = b->kids[1] = NULL;
 556
 557         /* Add original triangles */
 558         roam_triangle_sync_neighbors(s->t.l, sl, s);
 559         roam_triangle_sync_neighbors(s->t.r, sr, s);
 560         roam_triangle_sync_neighbors(b->t.l, bl, b);
 561         roam_triangle_sync_neighbors(b->t.r, br, b);
 562
 563         roam_triangle_add(s, sl->t.b, b, sr->t.b, sphere);
 564         roam_triangle_add(b, bl->t.b, s, br->t.b, sphere);
 565
 566         roam_triangle_sync_neighbors(sl->t.b, sl, s);
 567         roam_triangle_sync_neighbors(sr->t.b, sr, s);
 568         roam_triangle_sync_neighbors(bl->t.b, bl, b);
 569         roam_triangle_sync_neighbors(br->t.b, br, b);
 570
 571         /* Remove child triangles */
 572         roam_triangle_remove(sl, sphere);
 573         roam_triangle_remove(sr, sphere);
 574         roam_triangle_remove(bl, sphere);
 575         roam_triangle_remove(br, sphere);
 576
 577         /* Add/Remove triangles */
 578         if (s->t.l->t.l == s->t.r->t.r &&
 579             s->t.l->t.l != s && s->parent) {
 580                 roam_diamond_update_errors(s->parent, sphere);
 581                 roam_diamond_add(s->parent, sphere);
 582         }
 583
 584         if (b->t.l->t.l == b->t.r->t.r &&
 585             b->t.l->t.l != b && b->parent) {
 586                 roam_diamond_update_errors(b->parent, sphere);
 587                 roam_diamond_add(b->parent, sphere);
 588         }
 589
 590         /* Remove and free diamond and child triangles */
 591         roam_diamond_remove(diamond, sphere);
 592         g_assert(sl->p.m == sr->p.m &&
 593                  sr->p.m == bl->p.m &&
 594                  bl->p.m == br->p.m);
 595         g_assert(sl->p.m->tris == 0);
 596         roam_triangle_free(sl);
 597         roam_triangle_free(sr);
 598         roam_triangle_free(bl);
 599         roam_triangle_free(br);
 600         g_free(diamond);
 601 }
 602
 603 /**
 604  * roam_diamond_update_errors:
 605  * @diamond: the diamond
 606  * @sphere:  the sphere to use when updating errors
 607  *
 608  * Update the error value associated with a diamond. Called when the view
 609  * changes.
 610  */
 611 void roam_diamond_update_errors(RoamDiamond *diamond, RoamSphere *sphere)
 612 {
 613         roam_triangle_update_errors(diamond->parents[0], sphere);
 614         roam_triangle_update_errors(diamond->parents[1], sphere);
 615         diamond->error = MAX(diamond->parents[0]->error, diamond->parents[1]->error);
 616 }
 617
 618 /**************
 619  * RoamSphere *
 620  **************/
 621 /**
 622  * roam_sphere_new:
 623  *
 624  * Create a new sphere
 625  *
 626  * Returns: the sphere
 627  */
 628 RoamSphere *roam_sphere_new()
 629 {
 630         RoamSphere *sphere = g_new0(RoamSphere, 1);
 631         sphere->polys       = 8;
 632         sphere->triangles   = g_pqueue_new((GCompareDataFunc)tri_cmp, NULL);
 633         sphere->diamonds    = g_pqueue_new((GCompareDataFunc)dia_cmp, NULL);
 634         sphere->view        = g_new0(RoamView, 1);
 635
 636         RoamPoint *vertexes[] = {
 637                 roam_point_new( 90,   0,  0), // 0 (North)
 638                 roam_point_new(-90,   0,  0), // 1 (South)
 639                 roam_point_new(  0,   0,  0), // 2 (Europe/Africa)
 640                 roam_point_new(  0,  90,  0), // 3 (Asia,East)
 641                 roam_point_new(  0, 180,  0), // 4 (Pacific)
 642                 roam_point_new(  0, -90,  0), // 5 (Americas,West)
 643         };
 644         int _triangles[][2][3] = {
 645                 /*lv mv rv   ln, bn, rn */
 646                 {{2,0,3}, {3, 4, 1}}, // 0
 647                 {{3,0,4}, {0, 5, 2}}, // 1
 648                 {{4,0,5}, {1, 6, 3}}, // 2
 649                 {{5,0,2}, {2, 7, 0}}, // 3
 650                 {{3,1,2}, {5, 0, 7}}, // 4
 651                 {{4,1,3}, {6, 1, 4}}, // 5
 652                 {{5,1,4}, {7, 2, 5}}, // 6
 653                 {{2,1,5}, {4, 3, 6}}, // 7
 654         };
 655
 656         for (int i = 0; i < 6; i++)
 657                 roam_point_update_height(vertexes[i]);
 658         for (int i = 0; i < 8; i++)
 659                 sphere->roots[i] = roam_triangle_new(
 660                         vertexes[_triangles[i][0][0]],
 661                         vertexes[_triangles[i][0][1]],
 662                         vertexes[_triangles[i][0][2]],
 663                         NULL);
 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         glGetDoublev (GL_MODELVIEW_MATRIX,  sphere->view->model);
 689         glGetDoublev (GL_PROJECTION_MATRIX, sphere->view->proj);
 690         glGetIntegerv(GL_VIEWPORT,          sphere->view->view);
 691         sphere->view->version++;
 692 }
 693
 694 /**
 695  * roam_sphere_update_errors
 696  * @sphere: the sphere
 697  *
 698  * Update triangle and diamond errors in the sphere.
 699  */
 700 void roam_sphere_update_errors(RoamSphere *sphere)
 701 {
 702         g_debug("RoamSphere: update_errors - polys=%d", sphere->polys);
 703
 704         static int version = 0;
 705         if (version == sphere->view->version)
 706                 return;
 707         version = sphere->view->version;
 708
 709         GPtrArray *tris = g_pqueue_get_array(sphere->triangles);
 710         GPtrArray *dias = g_pqueue_get_array(sphere->diamonds);
 711
 712         for (int i = 0; i < tris->len; i++) {
 713                 RoamTriangle *triangle = tris->pdata[i];
 714                 roam_triangle_update_errors(triangle, sphere);
 715                 g_pqueue_priority_changed(sphere->triangles, triangle->handle);
 716         }
 717
 718         for (int i = 0; i < dias->len; i++) {
 719                 RoamDiamond *diamond = dias->pdata[i];
 720                 roam_diamond_update_errors(diamond, sphere);
 721                 g_pqueue_priority_changed(sphere->diamonds, diamond->handle);
 722         }
 723
 724         g_ptr_array_free(tris, TRUE);
 725         g_ptr_array_free(dias, TRUE);
 726 }
 727
 728 /**
 729  * roam_sphere_split_one
 730  * @sphere: the sphere
 731  *
 732  * Split the triangle with the greatest error.
 733  */
 734 void roam_sphere_split_one(RoamSphere *sphere)
 735 {
 736         RoamTriangle *to_split = g_pqueue_peek(sphere->triangles);
 737         if (!to_split) return;
 738         roam_triangle_split(to_split, sphere);
 739 }
 740
 741 /**
 742  * roam_sphere_merge_one
 743  * @sphere: the sphere
 744  *
 745  * Merge the diamond with the lowest error.
 746  */
 747 void roam_sphere_merge_one(RoamSphere *sphere)
 748 {
 749         RoamDiamond *to_merge = g_pqueue_peek(sphere->diamonds);
 750         if (!to_merge) return;
 751         roam_diamond_merge(to_merge, sphere);
 752 }
 753
 754 /**
 755  * roam_sphere_split_merge
 756  * @sphere: the sphere
 757  *
 758  * Perform a predetermined number split-merge iterations.
 759  *
 760  * Returns: the number splits and merges done
 761  */
 762 gint roam_sphere_split_merge(RoamSphere *sphere)
 763 {
 764         gint iters = 0, max_iters = 500;
 765         //gint target = 20000;
 766         //gint target = 4000;
 767         gint target = 2000;
 768         //gint target = 500;
 769
 770         if (!sphere->view)
 771                 return 0;
 772
 773         if (target - sphere->polys > 100) {
 774                 //g_debug("RoamSphere: split_merge - Splitting %d - %d > 100", target, sphere->polys);
 775                 while (sphere->polys < target && iters++ < max_iters)
 776                         roam_sphere_split_one(sphere);
 777         }
 778
 779         if (sphere->polys - target > 100) {
 780                 //g_debug("RoamSphere: split_merge - Merging %d - %d > 100", sphere->polys, target);
 781                 while (sphere->polys > target && iters++ < max_iters)
 782                         roam_sphere_merge_one(sphere);
 783         }
 784
 785         while (((RoamTriangle*)g_pqueue_peek(sphere->triangles))->error >
 786                ((RoamDiamond *)g_pqueue_peek(sphere->diamonds ))->error &&
 787                iters++ < max_iters) {
 788                 //g_debug("RoamSphere: split_merge - Fixing 1 %f > %f && %d < %d",
 789                 //              ((RoamTriangle*)g_pqueue_peek(sphere->triangles))->error,
 790                 //              ((RoamDiamond *)g_pqueue_peek(sphere->diamonds ))->error,
 791                 //              iters-1, max_iters);
 792                 roam_sphere_merge_one(sphere);
 793                 roam_sphere_split_one(sphere);
 794         }
 795
 796         return iters;
 797 }
 798
 799 /**
 800  * roam_sphere_draw:
 801  * @sphere: the sphere
 802  *
 803  * Draw the sphere. Use for debugging.
 804  */
 805 void roam_sphere_draw(RoamSphere *sphere)
 806 {
 807         g_debug("RoamSphere: draw");
 808         g_pqueue_foreach(sphere->triangles, (GFunc)roam_triangle_draw, NULL);
 809 }
 810
 811 /**
 812  * roam_sphere_draw_normals
 813  * @sphere: the sphere
 814  *
 815  * Draw all the surface normal vectors for the sphere. Used while debugging.
 816  */
 817 void roam_sphere_draw_normals(RoamSphere *sphere)
 818 {
 819         g_debug("RoamSphere: draw_normal");
 820         g_pqueue_foreach(sphere->triangles, (GFunc)roam_triangle_draw_normal, NULL);
 821 }
 822
 823 static GList *_roam_sphere_get_leaves(RoamTriangle *triangle, GList *list, gboolean all)
 824 {
 825         if (triangle->kids[0] && triangle->kids[1]) {
 826                 if (all) list = g_list_prepend(list, triangle);
 827                 list = _roam_sphere_get_leaves(triangle->kids[0], list, all);
 828                 list = _roam_sphere_get_leaves(triangle->kids[1], list, all);
 829                 return list;
 830         } else {
 831                 return g_list_prepend(list, triangle);
 832         }
 833 }
 834
 835 static GList *_roam_sphere_get_intersect_rec(RoamTriangle *triangle, GList *list,
 836                 gboolean all, gdouble n, gdouble s, gdouble e, gdouble w)
 837 {
 838         gdouble tn = triangle->edge.n;
 839         gdouble ts = triangle->edge.s;
 840         gdouble te = triangle->edge.e;
 841         gdouble tw = triangle->edge.w;
 842
 843         gboolean debug = FALSE  &&
 844                 n==90 && s==45 && e==-90 && w==-180 &&
 845                 ts > 44 && ts < 46;
 846
 847         if (debug)
 848                 g_message("t=%p: %f < %f || %f > %f || %f < %f || %f > %f",
 849                             triangle, tn,   s,   ts,   n,   te,   w,   tw,   e);
 850         if (tn <= s || ts >= n || te <= w || tw >= e) {
 851                 /* No intersect */
 852                 if (debug) g_message("no intersect");
 853                 return list;
 854         } else if (tn <= n && ts >= s && te <= e && tw >= w) {
 855                 /* Triangle is completely contained */
 856                 if (debug) g_message("contained");
 857                 if (all) list = g_list_prepend(list, triangle);
 858                 return _roam_sphere_get_leaves(triangle, list, all);
 859         } else if (triangle->kids[0] && triangle->kids[1]) {
 860                 /* Paritial intersect with children */
 861                 if (debug) g_message("edge w/ child");
 862                 if (all) list = g_list_prepend(list, triangle);
 863                 list = _roam_sphere_get_intersect_rec(triangle->kids[0], list, all, n, s, e, w);
 864                 list = _roam_sphere_get_intersect_rec(triangle->kids[1], list, all, n, s, e, w);
 865                 return list;
 866         } else {
 867                 /* This triangle is an edge case */
 868                 if (debug) g_message("edge");
 869                 return g_list_prepend(list, triangle);
 870         }
 871 }
 872
 873 /**
 874  * roam_sphere_get_intersect
 875  * @sphere: the sphere
 876  * @all: TRUE if non-leaf triangle should be returned as well
 877  * @n: the northern edge
 878  * @s: the southern edge
 879  * @e: the eastern edge
 880  * @w: the western edge
 881  *
 882  * Lookup triangles withing the sphere that intersect a given lat-lon box.
 883  *
 884  * Returns: the list of intersecting triangles.
 885  */
 886 /* Warning: This grabs pointers to triangles which can be changed by other
 887  * calls, e.g. split_merge. If you use this, you need to do some locking to
 888  * prevent the returned list from becomming stale. */
 889 GList *roam_sphere_get_intersect(RoamSphere *sphere, gboolean all,
 890                 gdouble n, gdouble s, gdouble e, gdouble w)
 891 {
 892         /* I think this is correct..
 893          * i_cost = cost for triangle-rectagnle intersect test
 894          * time = n_tiles * 2*tris_per_tile * i_cost
 895          * time = 30      * 2*333           * i_cost = 20000 * i_cost */
 896         GList *list = NULL;
 897         for (int i = 0; i < G_N_ELEMENTS(sphere->roots); i++)
 898                 list = _roam_sphere_get_intersect_rec(sphere->roots[i],
 899                                 list, all, n, s, e, w);
 900         return list;
 901 }
 902
 903 static void roam_sphere_free_tri(RoamTriangle *triangle)
 904 {
 905         if (--triangle->p.l->tris == 0) g_free(triangle->p.l);
 906         if (--triangle->p.m->tris == 0) g_free(triangle->p.m);
 907         if (--triangle->p.r->tris == 0) g_free(triangle->p.r);
 908         roam_triangle_free(triangle);
 909 }
 910
 911 /**
 912  * roam_sphere_free
 913  * @sphere: the sphere
 914  *
 915  * Free data associated with a sphere
 916  */
 917 void roam_sphere_free(RoamSphere *sphere)
 918 {
 919         g_debug("RoamSphere: free");
 920         /* Slow method, but it should work */
 921         while (sphere->polys > 8)
 922                 roam_sphere_merge_one(sphere);
 923         /* TODO: free points */
 924         g_pqueue_foreach(sphere->triangles, (GFunc)roam_sphere_free_tri, NULL);
 925         g_pqueue_free(sphere->triangles);
 926         g_pqueue_free(sphere->diamonds);
 927         g_free(sphere->view);
 928         g_free(sphere);
 929 }