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

   1 /*
   2  * Copyright (C) 2009 Andy Spencer <spenceal@rose-hulman.edu>
   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 #include <glib.h>
  19 #include <math.h>
  20 #include <string.h>
  21 #include "gpqueue.h"
  22 #include <GL/gl.h>
  23 #include <GL/glu.h>
  24
  25 #include "roam.h"
  26
  27 /**
  28  * TODO:
  29  *   - Optimize for memory consumption
  30  *   - Profile for computation speed
  31  *   - Target polygon count/detail
  32  */
  33
  34 /* Misc */
  35 RoamView *roam_view_get()
  36 {
  37         RoamView *view = g_new0(RoamView, 1);
  38         glGetDoublev (GL_MODELVIEW_MATRIX,  view->model);
  39         glGetDoublev (GL_PROJECTION_MATRIX, view->proj);
  40         glGetIntegerv(GL_VIEWPORT,          view->view);
  41         return view;
  42 }
  43
  44 /* For GPQueue comparators */
  45 static gint tri_cmp(RoamTriangle *a, RoamTriangle *b, gpointer data)
  46 {
  47         if      (a->error < b->error) return  1;
  48         else if (a->error > b->error) return -1;
  49         else                          return  0;
  50 }
  51 static gint dia_cmp(RoamDiamond *a, RoamDiamond *b, gpointer data)
  52 {
  53         if      (a->error < b->error) return -1;
  54         else if (a->error > b->error) return  1;
  55         else                          return  0;
  56 }
  57
  58 /*************
  59  * RoamPoint *
  60  *************/
  61 RoamPoint *roam_point_new(double x, double y, double z)
  62 {
  63         RoamPoint *self = g_new0(RoamPoint, 1);
  64         self->x = x;
  65         self->y = y;
  66         self->z = z;
  67         return self;
  68 }
  69 RoamPoint *roam_point_dup(RoamPoint *self)
  70 {
  71         RoamPoint *new = g_memdup(self, sizeof(RoamPoint));
  72         new->tris = 0;
  73         return new;
  74 }
  75 void roam_point_add_triangle(RoamPoint *self, RoamTriangle *triangle)
  76 {
  77         for (int i = 0; i < 3; i++) {
  78                 self->norm[i] *= self->tris;
  79                 self->norm[i] += triangle->norm[i];
  80         }
  81         self->tris++;
  82         for (int i = 0; i < 3; i++)
  83                 self->norm[i] /= self->tris;
  84 }
  85 void roam_point_remove_triangle(RoamPoint *self, RoamTriangle *triangle)
  86 {
  87         for (int i = 0; i < 3; i++) {
  88                 self->norm[i] *= self->tris;
  89                 self->norm[i] -= triangle->norm[i];
  90         }
  91         self->tris--;
  92         for (int i = 0; i < 3; i++)
  93                 self->norm[i] /= self->tris;
  94 }
  95 void roam_point_update(RoamPoint *self, RoamSphere *sphere, gboolean do_height)
  96 {
  97         if (!self->cached) {
  98                 /* Cache height */
  99                 if (do_height)
 100                         sphere->height_func(self, sphere->user_data);
 101
 102                 /* Cache projection */
 103                 gluProject(self->x, self->y, self->z,
 104                         sphere->view->model, sphere->view->proj, sphere->view->view,
 105                         &self->px, &self->py, &self->pz);
 106
 107                 self->cached = TRUE;
 108         }
 109 }
 110 void roam_point_clear(RoamPoint *self)
 111 {
 112         self->cached = FALSE;
 113 }
 114
 115 /****************
 116  * RoamTriangle *
 117  ****************/
 118 RoamTriangle *roam_triangle_new(RoamPoint *l, RoamPoint *m, RoamPoint *r)
 119 {
 120         RoamTriangle *self = g_new0(RoamTriangle, 1);
 121
 122         self->p.l = l;
 123         self->p.m = m;
 124         self->p.r = r;
 125
 126         self->error = 0;
 127
 128         /* Update normal */
 129         double pa[3];
 130         double pb[3];
 131         pa[0] = self->p.l->x - self->p.m->x;
 132         pa[1] = self->p.l->y - self->p.m->y;
 133         pa[2] = self->p.l->z - self->p.m->z;
 134
 135         pb[0] = self->p.r->x - self->p.m->x;
 136         pb[1] = self->p.r->y - self->p.m->y;
 137         pb[2] = self->p.r->z - self->p.m->z;
 138
 139         self->norm[0] = pa[1] * pb[2] - pa[2] * pb[1];
 140         self->norm[1] = pa[2] * pb[0] - pa[0] * pb[2];
 141         self->norm[2] = pa[0] * pb[1] - pa[1] * pb[0];
 142
 143         double total = sqrt(self->norm[0] * self->norm[0] +
 144                             self->norm[1] * self->norm[1] +
 145                             self->norm[2] * self->norm[2]);
 146
 147         self->norm[0] /= total;
 148         self->norm[1] /= total;
 149         self->norm[2] /= total;
 150
 151         //g_message("roam_triangle_new: %p", self);
 152         return self;
 153 }
 154
 155 void roam_triangle_add(RoamTriangle *self,
 156                 RoamTriangle *left, RoamTriangle *base, RoamTriangle *right,
 157                 RoamSphere *sphere)
 158 {
 159         self->t.l = left;
 160         self->t.b = base;
 161         self->t.r = right;
 162
 163         roam_point_add_triangle(self->p.l, self);
 164         roam_point_add_triangle(self->p.m, self);
 165         roam_point_add_triangle(self->p.r, self);
 166
 167         if (sphere->view)
 168                 roam_triangle_update(self, sphere);
 169
 170         self->handle = g_pqueue_push(sphere->triangles, self);
 171 }
 172
 173 void roam_triangle_remove(RoamTriangle *self, RoamSphere *sphere)
 174 {
 175         /* Update vertex normals */
 176         roam_point_remove_triangle(self->p.l, self);
 177         roam_point_remove_triangle(self->p.m, self);
 178         roam_point_remove_triangle(self->p.r, self);
 179
 180         g_pqueue_remove(sphere->triangles, self->handle);
 181 }
 182
 183 void roam_triangle_sync_neighbors(RoamTriangle *new, RoamTriangle *old, RoamTriangle *neigh)
 184 {
 185         if      (neigh->t.l == old) neigh->t.l = new;
 186         else if (neigh->t.b == old) neigh->t.b = new;
 187         else if (neigh->t.r == old) neigh->t.r = new;
 188         else g_assert_not_reached();
 189 }
 190
 191 gboolean roam_point_visible(RoamPoint *self, RoamSphere *sphere)
 192 {
 193         gint *view = sphere->view->view;
 194         return self->px > view[0] && self->px < view[2] &&
 195                self->py > view[1] && self->py < view[3] &&
 196                self->pz > 0       && self->pz < 1;
 197         //double x, y, z;
 198         //int view[4] = {0,0,1,1};
 199         //gluProject(self->x, self->y, self->z,
 200         //              sphere->view->model, sphere->view->proj, view,
 201         //              &x, &y, &z);
 202         //return !(x < 0 || x > 1 ||
 203         //         y < 0 || y > 1 ||
 204         //         z < 0 || z > 1);
 205 }
 206 gboolean roam_triangle_visible(RoamTriangle *self, RoamSphere *sphere)
 207 {
 208         /* Do this with a bounding box */
 209         return roam_point_visible(self->p.l, sphere) ||
 210                roam_point_visible(self->p.m, sphere) ||
 211                roam_point_visible(self->p.r, sphere);
 212 }
 213
 214 void roam_triangle_update(RoamTriangle *self, RoamSphere *sphere)
 215 {
 216         /* Update points */
 217         roam_point_update(self->p.l, sphere, TRUE);
 218         roam_point_update(self->p.m, sphere, TRUE);
 219         roam_point_update(self->p.r, sphere, TRUE);
 220
 221         /* Not exactly correct, could be out on both sides (middle in) */
 222         if (!roam_triangle_visible(self, sphere)) {
 223                 self->error = -1;
 224         } else {
 225                 RoamPoint *l = self->p.l;
 226                 RoamPoint *m = self->p.m;
 227                 RoamPoint *r = self->p.r;
 228
 229                 /* TODO: share this with the base */
 230                 RoamPoint base = { (l->x + r->x)/2,
 231                                    (l->y + r->y)/2,
 232                                    (l->z + r->z)/2 };
 233                 RoamPoint good = base;
 234                 roam_point_update(&base, sphere, FALSE);
 235                 roam_point_update(&good, sphere, TRUE);
 236
 237                 self->error = sqrt((base.px - good.px) * (base.px - good.px) +
 238                                    (base.py - good.py) * (base.py - good.py));
 239
 240                 /* Multiply by size of triangle */
 241                 double size = -( l->px * (m->py - r->py) +
 242                                  m->px * (r->py - l->py) +
 243                                  r->px * (l->py - m->py) ) / 2.0;
 244
 245                 /* Size < 0 == backface */
 246                 self->error *= size;
 247         }
 248 }
 249
 250 void roam_triangle_clear(RoamTriangle *self)
 251 {
 252         /* Clear points */
 253         roam_point_clear(self->p.l);
 254         roam_point_clear(self->p.m);
 255         roam_point_clear(self->p.r);
 256 }
 257
 258 void roam_triangle_split(RoamTriangle *self, RoamSphere *sphere)
 259 {
 260         //g_message("roam_triangle_split: %p, e=%f\n", self, self->error);
 261
 262         sphere->polys += 2;
 263
 264         if (self != self->t.b->t.b)
 265                 roam_triangle_split(self->t.b, sphere);
 266
 267         RoamTriangle *base = self->t.b;
 268
 269         /* Duplicate midpoint */
 270         RoamPoint *mid = roam_point_new(
 271                         (self->p.l->x + self->p.r->x)/2,
 272                         (self->p.l->y + self->p.r->y)/2,
 273                         (self->p.l->z + self->p.r->z)/2);
 274         roam_point_update(mid, sphere, TRUE);
 275
 276         /* Add new triangles */
 277         RoamTriangle *sl = roam_triangle_new(self->p.m, mid, self->p.l); // Self Left
 278         RoamTriangle *sr = roam_triangle_new(self->p.r, mid, self->p.m); // Self Right
 279         RoamTriangle *bl = roam_triangle_new(base->p.m, mid, base->p.l); // Base Left
 280         RoamTriangle *br = roam_triangle_new(base->p.r, mid, base->p.m); // Base Right
 281
 282         /*                tri,l,  base,      r,  sphere */
 283         roam_triangle_add(sl, sr, self->t.l, br, sphere);
 284         roam_triangle_add(sr, bl, self->t.r, sl, sphere);
 285         roam_triangle_add(bl, br, base->t.l, sr, sphere);
 286         roam_triangle_add(br, sl, base->t.r, bl, sphere);
 287
 288         roam_triangle_sync_neighbors(sl, self, self->t.l);
 289         roam_triangle_sync_neighbors(sr, self, self->t.r);
 290         roam_triangle_sync_neighbors(bl, base, base->t.l);
 291         roam_triangle_sync_neighbors(br, base, base->t.r);
 292
 293         /* Remove old triangles */
 294         roam_triangle_remove(self, sphere);
 295         roam_triangle_remove(base, sphere);
 296
 297         /* Add/Remove diamonds */
 298         RoamDiamond *diamond = roam_diamond_new(self, base, sl, sr, bl, br);
 299         roam_diamond_update(diamond, sphere);
 300         roam_diamond_add(diamond, sphere);
 301         roam_diamond_remove(self->parent, sphere);
 302         roam_diamond_remove(base->parent, sphere);
 303 }
 304
 305 void roam_triangle_draw_normal(RoamTriangle *self)
 306 {
 307         double center[] = {
 308                 (self->p.l->x + self->p.m->x + self->p.r->x)/3.0,
 309                 (self->p.l->y + self->p.m->y + self->p.r->y)/3.0,
 310                 (self->p.l->z + self->p.m->z + self->p.r->z)/3.0,
 311         };
 312         double end[] = {
 313                 center[0]+self->norm[0]/2,
 314                 center[1]+self->norm[1]/2,
 315                 center[2]+self->norm[2]/2,
 316         };
 317         glBegin(GL_LINES);
 318         glVertex3dv(center);
 319         glVertex3dv(end);
 320         glEnd();
 321 }
 322
 323 /***************
 324  * RoamDiamond *
 325  ***************/
 326 RoamDiamond *roam_diamond_new(
 327                 RoamTriangle *parent0, RoamTriangle *parent1,
 328                 RoamTriangle *kid0, RoamTriangle *kid1,
 329                 RoamTriangle *kid2, RoamTriangle *kid3)
 330 {
 331         RoamDiamond *self = g_new0(RoamDiamond, 1);
 332
 333         self->kids[0] = kid0;
 334         self->kids[1] = kid1;
 335         self->kids[2] = kid2;
 336         self->kids[3] = kid3;
 337
 338         kid0->parent = self;
 339         kid1->parent = self;
 340         kid2->parent = self;
 341         kid3->parent = self;
 342
 343         self->parents[0] = parent0;
 344         self->parents[1] = parent1;
 345
 346         return self;
 347 }
 348 void roam_diamond_add(RoamDiamond *self, RoamSphere *sphere)
 349 {
 350         self->active = TRUE;
 351         self->error  = MAX(self->parents[0]->error, self->parents[1]->error);
 352         self->handle = g_pqueue_push(sphere->diamonds, self);
 353 }
 354 void roam_diamond_remove(RoamDiamond *self, RoamSphere *sphere)
 355 {
 356         if (self && self->active) {
 357                 self->active = FALSE;
 358                 g_pqueue_remove(sphere->diamonds, self->handle);
 359         }
 360 }
 361 void roam_diamond_merge(RoamDiamond *self, RoamSphere *sphere)
 362 {
 363         //g_message("roam_diamond_merge: %p, e=%f\n", self, self->error);
 364
 365         sphere->polys -= 2;
 366
 367         /* TODO: pick the best split */
 368         RoamTriangle **kids = self->kids;
 369
 370         /* Create triangles */
 371         RoamTriangle *tri  = self->parents[0];
 372         RoamTriangle *base = self->parents[1];
 373
 374         roam_triangle_add(tri,  kids[0]->t.b, base, kids[1]->t.b, sphere);
 375         roam_triangle_add(base, kids[2]->t.b, tri,  kids[3]->t.b, sphere);
 376
 377         roam_triangle_sync_neighbors(tri,  kids[0], kids[0]->t.b);
 378         roam_triangle_sync_neighbors(tri,  kids[1], kids[1]->t.b);
 379         roam_triangle_sync_neighbors(base, kids[2], kids[2]->t.b);
 380         roam_triangle_sync_neighbors(base, kids[3], kids[3]->t.b);
 381
 382         /* Remove triangles */
 383         roam_triangle_remove(kids[0], sphere);
 384         roam_triangle_remove(kids[1], sphere);
 385         roam_triangle_remove(kids[2], sphere);
 386         roam_triangle_remove(kids[3], sphere);
 387
 388         /* Add/Remove triangles */
 389         if (tri->t.l->t.l == tri->t.r->t.r &&
 390             tri->t.l->t.l != tri && tri->parent) {
 391                 roam_diamond_update(tri->parent, sphere);
 392                 roam_diamond_add(tri->parent, sphere);
 393         }
 394
 395         if (base->t.l->t.l == base->t.r->t.r &&
 396             base->t.l->t.l != base && base->parent) {
 397                 roam_diamond_update(base->parent, sphere);
 398                 roam_diamond_add(base->parent, sphere);
 399         }
 400
 401         /* Remove and free diamond and child triangles */
 402         roam_diamond_remove(self, sphere);
 403         g_assert(self->kids[0]->p.m == self->kids[1]->p.m &&
 404                  self->kids[1]->p.m == self->kids[2]->p.m &&
 405                  self->kids[2]->p.m == self->kids[3]->p.m);
 406         g_assert(self->kids[0]->p.m->tris == 0);
 407         g_free(self->kids[0]->p.m);
 408         g_free(self->kids[0]);
 409         g_free(self->kids[1]);
 410         g_free(self->kids[2]);
 411         g_free(self->kids[3]);
 412         g_free(self);
 413 }
 414 void roam_diamond_update(RoamDiamond *self, RoamSphere *sphere)
 415 {
 416         roam_triangle_update(self->parents[0], sphere);
 417         roam_triangle_update(self->parents[1], sphere);
 418         self->error = MAX(self->parents[0]->error, self->parents[1]->error);
 419 }
 420
 421 /**************
 422  * RoamSphere *
 423  **************/
 424 RoamSphere *roam_sphere_new(RoamTriFunc tri_func, RoamHeightFunc height_func, gpointer user_data)
 425 {
 426         RoamSphere *self = g_new0(RoamSphere, 1);
 427         self->tri_func    = tri_func;
 428         self->height_func = height_func;
 429         self->user_data   = user_data;
 430         self->polys       = 12;
 431         self->triangles   = g_pqueue_new((GCompareDataFunc)tri_cmp, NULL);
 432         self->diamonds    = g_pqueue_new((GCompareDataFunc)dia_cmp, NULL);
 433
 434         RoamPoint *vertexes[] = {
 435                 roam_point_new( 1, 1, 1), // 0
 436                 roam_point_new( 1, 1,-1), // 1
 437                 roam_point_new( 1,-1, 1), // 2
 438                 roam_point_new( 1,-1,-1), // 3
 439                 roam_point_new(-1, 1, 1), // 4
 440                 roam_point_new(-1, 1,-1), // 5
 441                 roam_point_new(-1,-1, 1), // 6
 442                 roam_point_new(-1,-1,-1), // 7
 443         };
 444         int _triangles[][2][3] = {
 445                 /*lv mv rv   ln, bn, rn */
 446                 {{3,2,0}, {10, 1, 7}}, // 0
 447                 {{0,1,3}, { 9, 0, 2}}, // 1
 448                 {{7,3,1}, {11, 3, 1}}, // 2
 449                 {{1,5,7}, { 8, 2, 4}}, // 3
 450                 {{6,7,5}, {11, 5, 3}}, // 4
 451                 {{5,4,6}, { 8, 4, 6}}, // 5
 452                 {{2,6,4}, {10, 7, 5}}, // 6
 453                 {{4,0,2}, { 9, 6, 0}}, // 7
 454                 {{4,5,1}, { 5, 9, 3}}, // 8
 455                 {{1,0,4}, { 1, 8, 7}}, // 9
 456                 {{6,2,3}, { 6,11, 0}}, // 10
 457                 {{3,7,6}, { 2,10, 4}}, // 11
 458         };
 459         RoamTriangle *triangles[12];
 460
 461         for (int i = 0; i < 12; i++)
 462                 triangles[i] = roam_triangle_new(
 463                         vertexes[_triangles[i][0][0]],
 464                         vertexes[_triangles[i][0][1]],
 465                         vertexes[_triangles[i][0][2]]);
 466         for (int i = 0; i < 12; i++)
 467                 roam_triangle_add(triangles[i],
 468                         triangles[_triangles[i][1][0]],
 469                         triangles[_triangles[i][1][1]],
 470                         triangles[_triangles[i][1][2]],
 471                         self);
 472
 473         return self;
 474 }
 475 void roam_sphere_update(RoamSphere *self)
 476 {
 477         g_debug("RoamSphere: update - polys=%d", self->polys);
 478         if (self->view) g_free(self->view);
 479         self->view = roam_view_get();
 480
 481         GPtrArray *tris = g_pqueue_get_array(self->triangles);
 482         GPtrArray *dias = g_pqueue_get_array(self->diamonds);
 483
 484         for (int i = 0; i < tris->len; i++) {
 485                 /* Note: this also updates points */
 486                 RoamTriangle *tri = tris->pdata[i];
 487                 roam_triangle_clear(tri);
 488                 roam_triangle_update(tri, self);
 489                 g_pqueue_priority_changed(self->triangles, tri->handle);
 490         }
 491
 492         for (int i = 0; i < dias->len; i++) {
 493                 RoamDiamond *dia = dias->pdata[i];
 494                 roam_diamond_update(dia, self);
 495                 g_pqueue_priority_changed(self->diamonds, dia->handle);
 496         }
 497
 498         g_ptr_array_free(tris, TRUE);
 499         g_ptr_array_free(dias, TRUE);
 500 }
 501
 502 void roam_sphere_split_one(RoamSphere *self)
 503 {
 504         RoamTriangle *to_split = g_pqueue_peek(self->triangles);
 505         if (!to_split) return;
 506         roam_triangle_split(to_split, self);
 507 }
 508 void roam_sphere_merge_one(RoamSphere *self)
 509 {
 510         RoamDiamond *to_merge = g_pqueue_peek(self->diamonds);
 511         if (!to_merge) return;
 512         roam_diamond_merge(to_merge, self);
 513 }
 514 gint roam_sphere_split_merge(RoamSphere *self)
 515 {
 516         gint iters = 0, max_iters = 500;
 517         gint target = 2000;
 518
 519         if (!self->view)
 520                 return 0;
 521
 522         if (target - self->polys > 100)
 523                 while (self->polys < target && iters++ < max_iters)
 524                         roam_sphere_split_one(self);
 525
 526         if (self->polys - target > 100)
 527                 while (self->polys > target && iters++ < max_iters)
 528                         roam_sphere_merge_one(self);
 529
 530         while (((RoamTriangle*)g_pqueue_peek(self->triangles))->error >
 531                ((RoamDiamond *)g_pqueue_peek(self->diamonds ))->error &&
 532                iters++ < max_iters) {
 533                 roam_sphere_merge_one(self);
 534                 roam_sphere_split_one(self);
 535         }
 536
 537         return iters;
 538 }
 539 void roam_sphere_draw(RoamSphere *self)
 540 {
 541         g_pqueue_foreach(self->triangles, (GFunc)self->tri_func, self->user_data);
 542 }
 543 void roam_sphere_draw_normals(RoamSphere *self)
 544 {
 545         g_pqueue_foreach(self->triangles, (GFunc)roam_triangle_draw_normal, NULL);
 546 }
 547 static void roam_sphere_free_tri(RoamTriangle *tri)
 548 {
 549         if (--tri->p.l->tris == 0) g_free(tri->p.l);
 550         if (--tri->p.m->tris == 0) g_free(tri->p.m);
 551         if (--tri->p.r->tris == 0) g_free(tri->p.r);
 552         g_free(tri);
 553 }
 554 void roam_sphere_free(RoamSphere *self)
 555 {
 556         /* Slow method, but it should work */
 557         while (self->polys > 12)
 558                 roam_sphere_merge_one(self);
 559         /* TODO: free points */
 560         g_pqueue_foreach(self->triangles, (GFunc)roam_sphere_free_tri, NULL);
 561         g_pqueue_free(self->triangles);
 562         g_pqueue_free(self->diamonds);
 563         g_free(self);
 564 }