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 #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 #include <GL/gl.h>
  35 #include <GL/glu.h>
  36
  37 #include "gpqueue.h"
  38 #include "grits-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         crossd3((gdouble*)triangle->p.l,
 210                 (gdouble*)triangle->p.m,
 211                 (gdouble*)triangle->p.r, triangle->norm);
 212         normd(triangle->norm);
 213
 214         /* Store bounding box, for get_intersect */
 215         RoamPoint *p[] = {l,m,r};
 216         triangle->edge.n =  -90; triangle->edge.s =  90;
 217         triangle->edge.e = -180; triangle->edge.w = 180;
 218         gboolean maxed = FALSE;
 219         for (int i = 0; i < G_N_ELEMENTS(p); i++) {
 220                 triangle->edge.n = MAX(triangle->edge.n, p[i]->lat);
 221                 triangle->edge.s = MIN(triangle->edge.s, p[i]->lat);
 222                 if (p[i]->lat == 90 || p[i]->lat == -90)
 223                         continue;
 224                 if (p[i]->lon == 180) {
 225                         maxed = TRUE;
 226                         continue;
 227                 }
 228                 triangle->edge.e = MAX(triangle->edge.e, p[i]->lon);
 229                 triangle->edge.w = MIN(triangle->edge.w, p[i]->lon);
 230         }
 231         if (maxed) {
 232                 if (triangle->edge.e < 0)
 233                         triangle->edge.w = -180;
 234                 else
 235                         triangle->edge.e =  180;
 236         }
 237
 238         //g_message("roam_triangle_new: %p", triangle);
 239         return triangle;
 240 }
 241
 242 /**
 243  * roam_triangle_free:
 244  * @triangle: the triangle
 245  *
 246  * Free data associated with a triangle
 247  */
 248 void roam_triangle_free(RoamTriangle *triangle)
 249 {
 250         g_free(triangle->split);
 251         g_free(triangle);
 252 }
 253
 254 /**
 255  * roam_triangle_add:
 256  * @triangle: the triangle
 257  * @left:     the left neighbor
 258  * @base:     the base neighbor
 259  * @right:    the right neighbor
 260  * @sphere:   the sphere to add the triangle to
 261  *
 262  * Add a triangle into the sphere's mesh using the given neighbors.
 263  */
 264 void roam_triangle_add(RoamTriangle *triangle,
 265                 RoamTriangle *left, RoamTriangle *base, RoamTriangle *right,
 266                 RoamSphere *sphere)
 267 {
 268         triangle->t.l = left;
 269         triangle->t.b = base;
 270         triangle->t.r = right;
 271
 272         roam_point_add_triangle(triangle->p.l, triangle);
 273         roam_point_add_triangle(triangle->p.m, triangle);
 274         roam_point_add_triangle(triangle->p.r, triangle);
 275
 276         if (sphere->view)
 277                 roam_triangle_update_errors(triangle, sphere);
 278
 279         triangle->handle = g_pqueue_push(sphere->triangles, triangle);
 280 }
 281
 282 /**
 283  * roam_triangle_remove:
 284  * @triangle: the triangle
 285  * @sphere:   the sphere to remove the triangle from
 286  *
 287  * Remove a triangle from a sphere's mesh.
 288  */
 289 void roam_triangle_remove(RoamTriangle *triangle, RoamSphere *sphere)
 290 {
 291         /* Update vertex normals */
 292         roam_point_remove_triangle(triangle->p.l, triangle);
 293         roam_point_remove_triangle(triangle->p.m, triangle);
 294         roam_point_remove_triangle(triangle->p.r, triangle);
 295
 296         g_pqueue_remove(sphere->triangles, triangle->handle);
 297 }
 298
 299 /* (neight->t.? == old) = new */
 300 static void roam_triangle_sync_neighbors(RoamTriangle *neigh, RoamTriangle *old, RoamTriangle *new)
 301 {
 302         if      (neigh->t.l == old) neigh->t.l = new;
 303         else if (neigh->t.b == old) neigh->t.b = new;
 304         else if (neigh->t.r == old) neigh->t.r = new;
 305 }
 306
 307 static gboolean roam_triangle_visible(RoamTriangle *triangle, RoamSphere *sphere)
 308 {
 309         RoamPoint *l = triangle->p.l;
 310         RoamPoint *m = triangle->p.m;
 311         RoamPoint *r = triangle->p.r;
 312         gdouble min_x = MIN(MIN(l->px, m->px), r->px);
 313         gdouble max_x = MAX(MAX(l->px, m->px), r->px);
 314         gdouble min_y = MIN(MIN(l->py, m->py), r->py);
 315         gdouble max_y = MAX(MAX(l->py, m->py), r->py);
 316         gint *view = sphere->view->view;
 317         return !(max_x < view[0] || min_x > view[2] ||
 318                  max_y < view[1] || min_y > view[3]) &&
 319                  l->pz > 0 && m->pz > 0 && r->pz > 0 &&
 320                  l->pz < 1 && m->pz < 1 && r->pz < 1;
 321 }
 322
 323 static gboolean roam_triangle_backface(RoamTriangle *triangle, RoamSphere *sphere)
 324 {
 325         RoamPoint *l = triangle->p.l;
 326         RoamPoint *m = triangle->p.m;
 327         RoamPoint *r = triangle->p.r;
 328         roam_point_update_projection(l, sphere->view);
 329         roam_point_update_projection(m, sphere->view);
 330         roam_point_update_projection(r, sphere->view);
 331         double size = -( l->px * (m->py - r->py) +
 332                          m->px * (r->py - l->py) +
 333                          r->px * (l->py - m->py) ) / 2.0;
 334         return size < 0;
 335 }
 336
 337 /**
 338  * roam_triangle_update_errors:
 339  * @triangle: the triangle
 340  * @sphere:   the sphere to use when updating errors
 341  *
 342  * Update the error value associated with a triangle. Called when the view
 343  * changes.
 344  */
 345 void roam_triangle_update_errors(RoamTriangle *triangle, RoamSphere *sphere)
 346 {
 347         /* Update points */
 348         roam_point_update_projection(triangle->p.l, sphere->view);
 349         roam_point_update_projection(triangle->p.m, sphere->view);
 350         roam_point_update_projection(triangle->p.r, sphere->view);
 351
 352         if (!roam_triangle_visible(triangle, sphere)) {
 353                 triangle->error = -1;
 354         } else {
 355                 roam_point_update_projection(triangle->split, sphere->view);
 356                 RoamPoint *l     = triangle->p.l;
 357                 RoamPoint *m     = triangle->p.m;
 358                 RoamPoint *r     = triangle->p.r;
 359                 RoamPoint *split = triangle->split;
 360
 361                 /*               l-r midpoint        projected l-r midpoint */
 362                 gdouble pxdist = (l->px + r->px)/2 - split->px;
 363                 gdouble pydist = (l->py + r->py)/2 - split->py;
 364
 365                 triangle->error = sqrt(pxdist*pxdist + pydist*pydist);
 366
 367                 /* Multiply by size of triangle */
 368                 double size = -( l->px * (m->py - r->py) +
 369                                  m->px * (r->py - l->py) +
 370                                  r->px * (l->py - m->py) ) / 2.0;
 371
 372                 /* Size < 0 == backface */
 373                 triangle->error *= size;
 374
 375                 /* Give some preference to "edge" faces */
 376                 if (roam_triangle_backface(triangle->t.l, sphere) ||
 377                     roam_triangle_backface(triangle->t.b, sphere) ||
 378                     roam_triangle_backface(triangle->t.r, sphere))
 379                         triangle->error *= 500;
 380         }
 381 }
 382
 383 /**
 384  * roam_triangle_split:
 385  * @triangle: the triangle
 386  * @sphere:   the sphere
 387  *
 388  * Split a triangle into two child triangles and update the sphere.
 389  * triangle
 390  */
 391 void roam_triangle_split(RoamTriangle *triangle, RoamSphere *sphere)
 392 {
 393         //g_message("roam_triangle_split: %p, e=%f\n", triangle, triangle->error);
 394
 395         sphere->polys += 2;
 396
 397         if (triangle != triangle->t.b->t.b)
 398                 roam_triangle_split(triangle->t.b, sphere);
 399         if (triangle != triangle->t.b->t.b)
 400                 g_assert_not_reached();
 401
 402         RoamTriangle *s = triangle;      // Self
 403         RoamTriangle *b = triangle->t.b; // Base
 404
 405         RoamDiamond *dia = roam_diamond_new(s, b);
 406
 407         /* Add new triangles */
 408         RoamPoint *mid = triangle->split;
 409         RoamTriangle *sl = s->kids[0] = roam_triangle_new(s->p.m, mid, s->p.l, dia); // Self Left
 410         RoamTriangle *sr = s->kids[1] = roam_triangle_new(s->p.r, mid, s->p.m, dia); // Self Right
 411         RoamTriangle *bl = b->kids[0] = roam_triangle_new(b->p.m, mid, b->p.l, dia); // Base Left
 412         RoamTriangle *br = b->kids[1] = roam_triangle_new(b->p.r, mid, b->p.m, dia); // Base Right
 413
 414         /*                triangle,l,  base,      r,  sphere */
 415         roam_triangle_add(sl, sr, s->t.l, br, sphere);
 416         roam_triangle_add(sr, bl, s->t.r, sl, sphere);
 417         roam_triangle_add(bl, br, b->t.l, sr, sphere);
 418         roam_triangle_add(br, sl, b->t.r, bl, sphere);
 419
 420         roam_triangle_sync_neighbors(s->t.l, s, sl);
 421         roam_triangle_sync_neighbors(s->t.r, s, sr);
 422         roam_triangle_sync_neighbors(b->t.l, b, bl);
 423         roam_triangle_sync_neighbors(b->t.r, b, br);
 424
 425         /* Remove old triangles */
 426         roam_triangle_remove(s, sphere);
 427         roam_triangle_remove(b, sphere);
 428
 429         /* Add/Remove diamonds */
 430         roam_diamond_update_errors(dia, sphere);
 431         roam_diamond_add(dia, sphere);
 432         roam_diamond_remove(s->parent, sphere);
 433         roam_diamond_remove(b->parent, sphere);
 434 }
 435
 436 /**
 437  * roam_triangle_draw:
 438  * @triangle: the triangle
 439  *
 440  * Draw the triangle. Use for debugging.
 441  */
 442 void roam_triangle_draw(RoamTriangle *triangle)
 443 {
 444         glBegin(GL_TRIANGLES);
 445         glNormal3dv(triangle->p.r->norm); glVertex3dv((double*)triangle->p.r);
 446         glNormal3dv(triangle->p.m->norm); glVertex3dv((double*)triangle->p.m);
 447         glNormal3dv(triangle->p.l->norm); glVertex3dv((double*)triangle->p.l);
 448         glEnd();
 449         return;
 450 }
 451
 452 /**
 453  * roam_triangle_draw_normal:
 454  * @triangle: the triangle
 455  *
 456  * Draw a normal vector for the triangle. Used while debugging.
 457  */
 458 void roam_triangle_draw_normal(RoamTriangle *triangle)
 459 {
 460         double center[] = {
 461                 (triangle->p.l->x + triangle->p.m->x + triangle->p.r->x)/3.0,
 462                 (triangle->p.l->y + triangle->p.m->y + triangle->p.r->y)/3.0,
 463                 (triangle->p.l->z + triangle->p.m->z + triangle->p.r->z)/3.0,
 464         };
 465         double end[] = {
 466                 center[0]+triangle->norm[0]*2000000,
 467                 center[1]+triangle->norm[1]*2000000,
 468                 center[2]+triangle->norm[2]*2000000,
 469         };
 470         glBegin(GL_LINES);
 471         glVertex3dv(center);
 472         glVertex3dv(end);
 473         glEnd();
 474 }
 475
 476 /***************
 477  * RoamDiamond *
 478  ***************/
 479 /**
 480  * roam_diamond_new:
 481  * @parent0: a parent triangle
 482  * @parent1: a parent triangle
 483  * @kid0:    a child triangle
 484  * @kid1:    a child triangle
 485  * @kid2:    a child triangle
 486  * @kid3:    a child triangle
 487  *
 488  * Create a diamond to store information about two split triangles.
 489  *
 490  * Returns: the new diamond
 491  */
 492 RoamDiamond *roam_diamond_new(RoamTriangle *parent0, RoamTriangle *parent1)
 493 {
 494         RoamDiamond *diamond = g_new0(RoamDiamond, 1);
 495         diamond->parents[0] = parent0;
 496         diamond->parents[1] = parent1;
 497         return diamond;
 498 }
 499
 500 /**
 501  * roam_diamond_add:
 502  * @diamond: the diamond
 503  * @sphere:  the sphere to add the diamond to
 504  *
 505  * Add a diamond into the sphere's pool of diamonds. It will be check for
 506  * possible merges.
 507  */
 508 void roam_diamond_add(RoamDiamond *diamond, RoamSphere *sphere)
 509 {
 510         diamond->active = TRUE;
 511         diamond->error  = MAX(diamond->parents[0]->error, diamond->parents[1]->error);
 512         diamond->handle = g_pqueue_push(sphere->diamonds, diamond);
 513 }
 514
 515 /**
 516  * roam_diamond_remove:
 517  * @diamond: the diamond
 518  * @sphere:  the sphere to remove the diamond from
 519  *
 520  * Remove a diamond from the sphere's pool of diamonds.
 521  */
 522 void roam_diamond_remove(RoamDiamond *diamond, RoamSphere *sphere)
 523 {
 524         if (diamond && diamond->active) {
 525                 diamond->active = FALSE;
 526                 g_pqueue_remove(sphere->diamonds, diamond->handle);
 527         }
 528 }
 529
 530 /**
 531  * roam_diamond_merge:
 532  * @diamond: the diamond
 533  * @sphere:  the sphere
 534  *
 535  * "Merge" a diamond back into two parent triangles. The original two triangles
 536  * are added back into the sphere and the four child triangles as well as the
 537  * diamond are removed.
 538  */
 539 void roam_diamond_merge(RoamDiamond *diamond, RoamSphere *sphere)
 540 {
 541         //g_message("roam_diamond_merge: %p, e=%f\n", diamond, diamond->error);
 542
 543         /* TODO: pick the best split */
 544         sphere->polys -= 2;
 545
 546         /* Use nicer temp names */
 547         RoamTriangle *s = diamond->parents[0]; // Self
 548         RoamTriangle *b = diamond->parents[1]; // Base
 549
 550         RoamTriangle *sl = s->kids[0];
 551         RoamTriangle *sr = s->kids[1];
 552         RoamTriangle *bl = b->kids[0];
 553         RoamTriangle *br = b->kids[1];
 554
 555         s->kids[0] = s->kids[1] = NULL;
 556         b->kids[0] = b->kids[1] = NULL;
 557
 558         /* Add original triangles */
 559         roam_triangle_sync_neighbors(s->t.l, sl, s);
 560         roam_triangle_sync_neighbors(s->t.r, sr, s);
 561         roam_triangle_sync_neighbors(b->t.l, bl, b);
 562         roam_triangle_sync_neighbors(b->t.r, br, b);
 563
 564         roam_triangle_add(s, sl->t.b, b, sr->t.b, sphere);
 565         roam_triangle_add(b, bl->t.b, s, br->t.b, sphere);
 566
 567         roam_triangle_sync_neighbors(sl->t.b, sl, s);
 568         roam_triangle_sync_neighbors(sr->t.b, sr, s);
 569         roam_triangle_sync_neighbors(bl->t.b, bl, b);
 570         roam_triangle_sync_neighbors(br->t.b, br, b);
 571
 572         /* Remove child triangles */
 573         roam_triangle_remove(sl, sphere);
 574         roam_triangle_remove(sr, sphere);
 575         roam_triangle_remove(bl, sphere);
 576         roam_triangle_remove(br, sphere);
 577
 578         /* Add/Remove triangles */
 579         if (s->t.l->t.l == s->t.r->t.r &&
 580             s->t.l->t.l != s && s->parent) {
 581                 roam_diamond_update_errors(s->parent, sphere);
 582                 roam_diamond_add(s->parent, sphere);
 583         }
 584
 585         if (b->t.l->t.l == b->t.r->t.r &&
 586             b->t.l->t.l != b && b->parent) {
 587                 roam_diamond_update_errors(b->parent, sphere);
 588                 roam_diamond_add(b->parent, sphere);
 589         }
 590
 591         /* Remove and free diamond and child triangles */
 592         roam_diamond_remove(diamond, sphere);
 593         g_assert(sl->p.m == sr->p.m &&
 594                  sr->p.m == bl->p.m &&
 595                  bl->p.m == br->p.m);
 596         g_assert(sl->p.m->tris == 0);
 597         roam_triangle_free(sl);
 598         roam_triangle_free(sr);
 599         roam_triangle_free(bl);
 600         roam_triangle_free(br);
 601         g_free(diamond);
 602 }
 603
 604 /**
 605  * roam_diamond_update_errors:
 606  * @diamond: the diamond
 607  * @sphere:  the sphere to use when updating errors
 608  *
 609  * Update the error value associated with a diamond. Called when the view
 610  * changes.
 611  */
 612 void roam_diamond_update_errors(RoamDiamond *diamond, RoamSphere *sphere)
 613 {
 614         roam_triangle_update_errors(diamond->parents[0], sphere);
 615         roam_triangle_update_errors(diamond->parents[1], sphere);
 616         diamond->error = MAX(diamond->parents[0]->error, diamond->parents[1]->error);
 617 }
 618
 619 /**************
 620  * RoamSphere *
 621  **************/
 622 /**
 623  * roam_sphere_new:
 624  *
 625  * Create a new sphere
 626  *
 627  * Returns: the sphere
 628  */
 629 RoamSphere *roam_sphere_new()
 630 {
 631         RoamSphere *sphere = g_new0(RoamSphere, 1);
 632         sphere->polys       = 8;
 633         sphere->triangles   = g_pqueue_new((GCompareDataFunc)tri_cmp, NULL);
 634         sphere->diamonds    = g_pqueue_new((GCompareDataFunc)dia_cmp, NULL);
 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         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 }