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annotate src/scene.cc @ 30:04803c702014

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debugging ...
author John Tsiombikas <nuclear@member.fsf.org>
date Sat, 21 Aug 2010 23:57:19 +0100
parents 353d80127627
children 92786fc3317e
rev   line source
John@15 1 #include <math.h>
nuclear@25 2 #include <float.h>
nuclear@26 3 #include <assert.h>
nuclear@22 4 #include "scene.h"
nuclear@27 5 #include "ogl.h"
nuclear@6 6
nuclear@26 7
nuclear@27 8 static void draw_kdtree(const KDNode *node, int level = 0);
nuclear@27 9 static bool build_kdtree(KDNode *kd, int level = 0);
nuclear@27 10 static float eval_cost(const std::list<const Face*> &faces, const AABBox &aabb, int axis, float par_sarea = 1.0);
nuclear@26 11 static void free_kdtree(KDNode *node);
nuclear@28 12 static void kdtree_gpu_flatten(KDNodeGPU *kdbuf, int idx, const KDNode *node, const Face *facebuf);
nuclear@27 13 static void print_item_counts(const KDNode *node, int level);
nuclear@26 14
nuclear@26 15
nuclear@26 16 static int accel_param[NUM_ACCEL_PARAMS] = {
nuclear@28 17 40, // max tree depth
nuclear@26 18 0, // max items per node (0 means ignore limit)
nuclear@26 19 5, // estimated traversal cost
nuclear@26 20 15 // estimated interseciton cost
nuclear@26 21 };
nuclear@26 22
nuclear@26 23
nuclear@26 24 void set_accel_param(int p, int v)
nuclear@26 25 {
nuclear@26 26 assert(p >= 0 && p < NUM_ACCEL_PARAMS);
nuclear@26 27 accel_param[p] = v;
nuclear@26 28 }
nuclear@26 29
nuclear@26 30
John@15 31 #define FEQ(a, b) (fabs((a) - (b)) < 1e-8)
John@15 32 bool Face::operator ==(const Face &f) const
John@15 33 {
John@15 34 for(int i=0; i<3; i++) {
John@15 35 for(int j=0; j<3; j++) {
John@15 36 if(!FEQ(v[i].pos[j], f.v[i].pos[j])) {
John@15 37 return false;
John@15 38 }
John@15 39 if(!FEQ(v[i].normal[j], f.v[i].normal[j])) {
John@15 40 return false;
John@15 41 }
John@15 42 }
John@15 43 if(!FEQ(normal[i], f.normal[i])) {
John@15 44 return false;
John@15 45 }
John@15 46 }
John@15 47 return true;
John@15 48 }
John@15 49
nuclear@25 50 float AABBox::calc_surface_area() const
nuclear@25 51 {
nuclear@25 52 float area1 = (max[0] - min[0]) * (max[1] - min[1]);
nuclear@25 53 float area2 = (max[3] - min[3]) * (max[1] - min[1]);
nuclear@25 54 float area3 = (max[0] - min[0]) * (max[3] - min[3]);
nuclear@25 55
nuclear@25 56 return 2.0f * (area1 + area2 + area3);
nuclear@25 57 }
nuclear@25 58
nuclear@26 59 KDNode::KDNode()
nuclear@26 60 {
nuclear@26 61 axis = 0;
nuclear@26 62 pt = 0.0;
nuclear@26 63 left = right = 0;
nuclear@26 64 num_faces = 0;
nuclear@26 65 }
nuclear@26 66
nuclear@25 67
nuclear@24 68 Scene::Scene()
nuclear@24 69 {
nuclear@24 70 facebuf = 0;
nuclear@24 71 num_faces = -1;
nuclear@24 72 kdtree = 0;
nuclear@28 73 kdbuf = 0;
nuclear@24 74 }
nuclear@24 75
nuclear@24 76 Scene::~Scene()
nuclear@24 77 {
nuclear@24 78 delete [] facebuf;
nuclear@28 79 delete [] kdbuf;
nuclear@28 80 free_kdtree(kdtree);
nuclear@24 81 }
nuclear@24 82
nuclear@13 83 bool Scene::add_mesh(Mesh *m)
nuclear@13 84 {
nuclear@13 85 // make sure triangles have material ids
nuclear@13 86 for(size_t i=0; i<m->faces.size(); i++) {
nuclear@13 87 m->faces[i].matid = m->matid;
nuclear@13 88 }
nuclear@24 89
nuclear@24 90 try {
nuclear@24 91 meshes.push_back(m);
nuclear@24 92 }
nuclear@24 93 catch(...) {
nuclear@24 94 return false;
nuclear@24 95 }
nuclear@24 96
nuclear@24 97 // invalidate facebuffer and count
nuclear@24 98 delete [] facebuf;
nuclear@24 99 facebuf = 0;
nuclear@24 100 num_faces = -1;
nuclear@24 101
nuclear@13 102 return true;
nuclear@13 103 }
nuclear@13 104
John@14 105 int Scene::get_num_meshes() const
John@14 106 {
John@14 107 return (int)meshes.size();
John@14 108 }
John@14 109
nuclear@13 110 int Scene::get_num_faces() const
nuclear@13 111 {
nuclear@24 112 if(num_faces >= 0) {
nuclear@24 113 return num_faces;
nuclear@24 114 }
nuclear@24 115
nuclear@24 116 num_faces = 0;
nuclear@13 117 for(size_t i=0; i<meshes.size(); i++) {
nuclear@13 118 num_faces += meshes[i]->faces.size();
nuclear@13 119 }
nuclear@13 120 return num_faces;
nuclear@13 121 }
nuclear@13 122
John@14 123 int Scene::get_num_materials() const
John@14 124 {
John@14 125 return (int)matlib.size();
John@14 126 }
John@14 127
John@14 128 Material *Scene::get_materials()
John@14 129 {
John@14 130 if(matlib.empty()) {
John@14 131 return 0;
John@14 132 }
John@14 133 return &matlib[0];
John@14 134 }
John@14 135
John@14 136 const Material *Scene::get_materials() const
John@14 137 {
John@14 138 if(matlib.empty()) {
John@14 139 return 0;
John@14 140 }
John@14 141 return &matlib[0];
John@14 142 }
nuclear@24 143
nuclear@24 144 const Face *Scene::get_face_buffer() const
nuclear@24 145 {
nuclear@24 146 if(facebuf) {
nuclear@24 147 return facebuf;
nuclear@24 148 }
nuclear@24 149
nuclear@24 150 int num_meshes = get_num_meshes();
nuclear@24 151
nuclear@24 152 printf("constructing face buffer with %d faces (out of %d meshes)\n", get_num_faces(), num_meshes);
nuclear@24 153 facebuf = new Face[num_faces];
nuclear@24 154 Face *fptr = facebuf;
nuclear@24 155
nuclear@24 156 for(int i=0; i<num_meshes; i++) {
nuclear@24 157 for(size_t j=0; j<meshes[i]->faces.size(); j++) {
nuclear@24 158 *fptr++ = meshes[i]->faces[j];
nuclear@24 159 }
nuclear@24 160 }
nuclear@24 161 return facebuf;
nuclear@24 162 }
nuclear@24 163
nuclear@28 164 const KDNodeGPU *Scene::get_kdtree_buffer() const
nuclear@28 165 {
nuclear@28 166 if(kdbuf) {
nuclear@28 167 return kdbuf;
nuclear@28 168 }
nuclear@28 169
nuclear@28 170 if(!kdtree) {
nuclear@28 171 ((Scene*)this)->build_kdtree();
nuclear@28 172 }
nuclear@28 173
nuclear@29 174 int max_nodes = (int)pow(2, kdtree_depth(kdtree)) - 1;
nuclear@29 175 printf("allocating storage for the complete tree (%d)\n", max_nodes);
nuclear@28 176
nuclear@29 177 kdbuf = new KDNodeGPU[max_nodes + 1];
nuclear@28 178 kdtree_gpu_flatten(kdbuf, 1, kdtree, get_face_buffer());
nuclear@28 179 return kdbuf;
nuclear@28 180 }
nuclear@28 181
nuclear@29 182 static int ipow(int x, int n)
nuclear@28 183 {
nuclear@29 184 assert(n >= 0);
nuclear@29 185
nuclear@29 186 int res = 1;
nuclear@29 187 for(int i=0; i<n; i++) {
nuclear@29 188 res *= x;
nuclear@28 189 }
nuclear@29 190 return res;
nuclear@28 191 }
nuclear@28 192
nuclear@29 193 int Scene::get_kdtree_buffer_size() const
nuclear@29 194 {
nuclear@29 195 // 2**depth - 1 nodes for the complete tree + 1 for the unused heap item 0.
nuclear@29 196 return ipow(2, kdtree_depth(kdtree)) * sizeof(KDNodeGPU);
nuclear@29 197 }
nuclear@24 198
nuclear@27 199 void Scene::draw_kdtree() const
nuclear@27 200 {
nuclear@27 201 glPushAttrib(GL_ENABLE_BIT);
nuclear@27 202 glDisable(GL_LIGHTING);
nuclear@27 203 glDepthMask(0);
nuclear@27 204
nuclear@27 205 glBegin(GL_LINES);
nuclear@27 206 ::draw_kdtree(kdtree, 0);
nuclear@27 207 glEnd();
nuclear@27 208
nuclear@27 209 glDepthMask(1);
nuclear@27 210 glPopAttrib();
nuclear@27 211 }
nuclear@27 212
nuclear@27 213 static float palette[][3] = {
nuclear@27 214 {0, 1, 0},
nuclear@27 215 {1, 0, 0},
nuclear@27 216 {0, 0, 1},
nuclear@27 217 {1, 1, 0},
nuclear@27 218 {0, 0, 1},
nuclear@27 219 {1, 0, 1}
nuclear@27 220 };
nuclear@27 221 static int pal_size = sizeof palette / sizeof *palette;
nuclear@27 222
nuclear@27 223 static void draw_kdtree(const KDNode *node, int level)
nuclear@27 224 {
nuclear@27 225 if(!node) return;
nuclear@27 226
nuclear@27 227 draw_kdtree(node->left, level + 1);
nuclear@27 228 draw_kdtree(node->right, level + 1);
nuclear@27 229
nuclear@27 230 glColor3fv(palette[level % pal_size]);
nuclear@27 231
nuclear@27 232 glVertex3fv(node->aabb.min);
nuclear@27 233 glVertex3f(node->aabb.max[0], node->aabb.min[1], node->aabb.min[2]);
nuclear@27 234 glVertex3f(node->aabb.max[0], node->aabb.min[1], node->aabb.min[2]);
nuclear@27 235 glVertex3f(node->aabb.max[0], node->aabb.max[1], node->aabb.min[2]);
nuclear@27 236 glVertex3f(node->aabb.max[0], node->aabb.max[1], node->aabb.min[2]);
nuclear@27 237 glVertex3f(node->aabb.min[0], node->aabb.max[1], node->aabb.min[2]);
nuclear@27 238 glVertex3f(node->aabb.min[0], node->aabb.max[1], node->aabb.min[2]);
nuclear@27 239 glVertex3fv(node->aabb.min);
nuclear@27 240
nuclear@27 241 glVertex3f(node->aabb.min[0], node->aabb.min[1], node->aabb.max[2]);
nuclear@27 242 glVertex3f(node->aabb.max[0], node->aabb.min[1], node->aabb.max[2]);
nuclear@27 243 glVertex3f(node->aabb.max[0], node->aabb.min[1], node->aabb.max[2]);
nuclear@27 244 glVertex3fv(node->aabb.max);
nuclear@27 245 glVertex3fv(node->aabb.max);
nuclear@27 246 glVertex3f(node->aabb.min[0], node->aabb.max[1], node->aabb.max[2]);
nuclear@27 247 glVertex3f(node->aabb.min[0], node->aabb.max[1], node->aabb.max[2]);
nuclear@27 248 glVertex3f(node->aabb.min[0], node->aabb.min[1], node->aabb.max[2]);
nuclear@27 249
nuclear@27 250 glVertex3fv(node->aabb.min);
nuclear@27 251 glVertex3f(node->aabb.min[0], node->aabb.min[1], node->aabb.max[2]);
nuclear@27 252 glVertex3f(node->aabb.max[0], node->aabb.min[1], node->aabb.min[2]);
nuclear@27 253 glVertex3f(node->aabb.max[0], node->aabb.min[1], node->aabb.max[2]);
nuclear@27 254 glVertex3f(node->aabb.max[0], node->aabb.max[1], node->aabb.min[2]);
nuclear@27 255 glVertex3fv(node->aabb.max);
nuclear@27 256 glVertex3f(node->aabb.min[0], node->aabb.max[1], node->aabb.min[2]);
nuclear@27 257 glVertex3f(node->aabb.min[0], node->aabb.max[1], node->aabb.max[2]);
nuclear@27 258 }
nuclear@27 259
nuclear@27 260 bool Scene::build_kdtree()
nuclear@24 261 {
nuclear@29 262 assert(kdtree == 0);
nuclear@29 263
nuclear@24 264 const Face *faces = get_face_buffer();
nuclear@24 265 int num_faces = get_num_faces();
nuclear@24 266
nuclear@25 267 printf("Constructing kd-tree out of %d faces ...\n", num_faces);
nuclear@25 268
nuclear@27 269 int icost = accel_param[ACCEL_PARAM_COST_INTERSECT];
nuclear@27 270 int tcost = accel_param[ACCEL_PARAM_COST_TRAVERSE];
nuclear@27 271 printf(" max items per leaf: %d\n", accel_param[ACCEL_PARAM_MAX_NODE_ITEMS]);
nuclear@27 272 printf(" SAH parameters - tcost: %d - icost: %d\n", tcost, icost);
nuclear@27 273
nuclear@25 274 free_kdtree(kdtree);
nuclear@25 275 kdtree = new KDNode;
nuclear@25 276
nuclear@25 277 /* Start the construction of the kdtree by adding all faces of the scene
nuclear@25 278 * to the new root node. At the same time calculate the root's AABB.
nuclear@25 279 */
nuclear@25 280 kdtree->aabb.min[0] = kdtree->aabb.min[1] = kdtree->aabb.min[2] = FLT_MAX;
nuclear@25 281 kdtree->aabb.max[0] = kdtree->aabb.max[1] = kdtree->aabb.max[2] = -FLT_MAX;
nuclear@25 282
nuclear@24 283 for(int i=0; i<num_faces; i++) {
nuclear@25 284 const Face *face = faces + i;
nuclear@25 285
nuclear@25 286 // for each vertex of the face ...
nuclear@25 287 for(int j=0; j<3; j++) {
nuclear@25 288 const float *pos = face->v[j].pos;
nuclear@25 289
nuclear@25 290 // for each element (xyz) of the position vector ...
nuclear@25 291 for(int k=0; k<3; k++) {
nuclear@25 292 if(pos[k] < kdtree->aabb.min[k]) {
nuclear@25 293 kdtree->aabb.min[k] = pos[k];
nuclear@25 294 }
nuclear@25 295 if(pos[k] > kdtree->aabb.max[k]) {
nuclear@25 296 kdtree->aabb.max[k] = pos[k];
nuclear@25 297 }
nuclear@25 298 }
nuclear@25 299 }
nuclear@25 300
nuclear@25 301 kdtree->faces.push_back(face); // add the face
nuclear@26 302 kdtree->num_faces++;
nuclear@24 303 }
nuclear@24 304
nuclear@26 305 // calculate the heuristic for the root
nuclear@26 306 kdtree->cost = eval_cost(kdtree->faces, kdtree->aabb, kdtree->axis);
nuclear@26 307
nuclear@25 308 // now proceed splitting the root recursively
nuclear@27 309 if(!::build_kdtree(kdtree)) {
nuclear@27 310 fprintf(stderr, "failed to build kdtree\n");
nuclear@27 311 return false;
nuclear@27 312 }
nuclear@27 313
nuclear@27 314 printf(" tree depth: %d\n", kdtree_depth(kdtree));
nuclear@27 315 print_item_counts(kdtree, 0);
nuclear@27 316 return true;
nuclear@24 317 }
nuclear@24 318
nuclear@27 319 static bool build_kdtree(KDNode *kd, int level)
nuclear@24 320 {
nuclear@28 321 int opt_max_depth = accel_param[ACCEL_PARAM_MAX_TREE_DEPTH];
nuclear@26 322 int opt_max_items = accel_param[ACCEL_PARAM_MAX_NODE_ITEMS];
nuclear@27 323 int tcost = accel_param[ACCEL_PARAM_COST_TRAVERSE];
nuclear@27 324
nuclear@28 325 if(kd->num_faces == 0 || level >= opt_max_depth) {
nuclear@27 326 return true;
nuclear@25 327 }
nuclear@25 328
nuclear@27 329 int axis = level % 3;
nuclear@27 330 //float parent_sa = kd->aabb.calc_surface_area();
nuclear@26 331
nuclear@26 332 float best_cost[2], best_sum_cost = FLT_MAX;
nuclear@26 333 float best_split;
nuclear@26 334
nuclear@26 335 std::list<const Face*>::iterator it = kd->faces.begin();
nuclear@26 336 while(it != kd->faces.end()) {
nuclear@26 337 const Face *face = *it++;
nuclear@26 338
nuclear@26 339 for(int i=0; i<3; i++) {
nuclear@26 340 AABBox aabb_left, aabb_right;
nuclear@26 341 const float *split = face->v[i].pos;
nuclear@26 342
nuclear@26 343 aabb_left = aabb_right = kd->aabb;
nuclear@26 344 aabb_left.max[axis] = split[axis];
nuclear@26 345 aabb_right.min[axis] = split[axis];
nuclear@26 346
nuclear@26 347 float left_cost = eval_cost(kd->faces, aabb_left, axis);
nuclear@26 348 float right_cost = eval_cost(kd->faces, aabb_right, axis);
nuclear@27 349 float sum_cost = left_cost + right_cost - tcost; // tcost is added twice
nuclear@26 350
nuclear@26 351 if(sum_cost < best_sum_cost) {
nuclear@26 352 best_cost[0] = left_cost;
nuclear@26 353 best_cost[1] = right_cost;
nuclear@26 354 best_sum_cost = sum_cost;
nuclear@26 355 best_split = split[axis];
nuclear@26 356 }
nuclear@26 357 }
nuclear@26 358 }
nuclear@26 359
nuclear@29 360 //printf("current cost: %f, best_cost: %f\n", kd->cost, best_sum_cost);
nuclear@27 361 if(best_sum_cost > kd->cost && (opt_max_items == 0 || kd->num_faces <= opt_max_items)) {
nuclear@27 362 return true; // stop splitting if it doesn't reduce the cost
nuclear@26 363 }
nuclear@26 364 kd->pt = best_split;
nuclear@26 365
nuclear@26 366 // create the two children
nuclear@26 367 KDNode *kdleft, *kdright;
nuclear@26 368 kdleft = new KDNode;
nuclear@26 369 kdright = new KDNode;
nuclear@26 370
nuclear@26 371 kdleft->aabb = kdright->aabb = kd->aabb;
nuclear@26 372
nuclear@26 373 kdleft->aabb.max[axis] = best_split;
nuclear@26 374 kdright->aabb.min[axis] = best_split;
nuclear@26 375
nuclear@26 376 kdleft->cost = best_cost[0];
nuclear@26 377 kdright->cost = best_cost[1];
nuclear@26 378
nuclear@27 379 //kdleft->axis = kdright->axis = (axis + 1) % 3;
nuclear@27 380
nuclear@26 381 it = kd->faces.begin();
nuclear@26 382 while(it != kd->faces.end()) {
nuclear@26 383 const Face *face = *it++;
nuclear@26 384
nuclear@26 385 if(face->v[0].pos[axis] < best_split ||
nuclear@26 386 face->v[1].pos[axis] < best_split ||
nuclear@26 387 face->v[2].pos[axis] < best_split) {
nuclear@26 388 kdleft->faces.push_back(face);
nuclear@26 389 kdleft->num_faces++;
nuclear@26 390 }
nuclear@26 391 if(face->v[0].pos[axis] >= best_split ||
nuclear@26 392 face->v[1].pos[axis] >= best_split ||
nuclear@26 393 face->v[2].pos[axis] >= best_split) {
nuclear@26 394 kdright->faces.push_back(face);
nuclear@26 395 kdright->num_faces++;
nuclear@26 396 }
nuclear@26 397 }
nuclear@27 398 kd->faces.clear(); // only leaves have faces
nuclear@26 399
nuclear@26 400 kd->left = kdleft;
nuclear@26 401 kd->right = kdright;
nuclear@27 402
nuclear@27 403 return build_kdtree(kd->left, level + 1) && build_kdtree(kd->right, level + 1);
nuclear@26 404 }
nuclear@26 405
nuclear@27 406 static float eval_cost(const std::list<const Face*> &faces, const AABBox &aabb, int axis, float par_sarea)
nuclear@26 407 {
nuclear@26 408 int num_inside = 0;
nuclear@26 409 int tcost = accel_param[ACCEL_PARAM_COST_TRAVERSE];
nuclear@26 410 int icost = accel_param[ACCEL_PARAM_COST_INTERSECT];
nuclear@26 411
nuclear@26 412 std::list<const Face*>::const_iterator it = faces.begin();
nuclear@26 413 while(it != faces.end()) {
nuclear@26 414 const Face *face = *it++;
nuclear@26 415
nuclear@26 416 for(int i=0; i<3; i++) {
nuclear@26 417 if(face->v[i].pos[axis] >= aabb.min[axis] && face->v[i].pos[axis] < aabb.max[axis]) {
nuclear@26 418 num_inside++;
nuclear@26 419 break;
nuclear@26 420 }
nuclear@26 421 }
nuclear@26 422 }
nuclear@26 423
nuclear@27 424 float sarea = aabb.calc_surface_area();
nuclear@27 425 if(sarea < 1e-8) {
nuclear@27 426 return FLT_MAX; // heavily penalize 0-area voxels
nuclear@27 427 }
nuclear@27 428
nuclear@27 429 return tcost + (sarea / par_sarea) * num_inside * icost;
nuclear@24 430 }
nuclear@25 431
nuclear@25 432 static void free_kdtree(KDNode *node)
nuclear@25 433 {
nuclear@25 434 if(node) {
nuclear@25 435 free_kdtree(node->left);
nuclear@25 436 free_kdtree(node->right);
nuclear@25 437 delete node;
nuclear@25 438 }
nuclear@25 439 }
nuclear@27 440
nuclear@28 441 int kdtree_depth(const KDNode *node)
nuclear@27 442 {
nuclear@27 443 if(!node) return 0;
nuclear@27 444
nuclear@27 445 int left = kdtree_depth(node->left);
nuclear@27 446 int right = kdtree_depth(node->right);
nuclear@27 447 return (left > right ? left : right) + 1;
nuclear@27 448 }
nuclear@27 449
nuclear@28 450 int kdtree_nodes(const KDNode *node)
nuclear@28 451 {
nuclear@28 452 if(!node) return 0;
nuclear@28 453 return kdtree_nodes(node->left) + kdtree_nodes(node->right) + 1;
nuclear@28 454 }
nuclear@28 455
nuclear@28 456 #define MAX_FACES (sizeof dest->face_idx / sizeof *dest->face_idx)
nuclear@28 457 static void kdtree_gpu_flatten(KDNodeGPU *kdbuf, int idx, const KDNode *node, const Face *facebuf)
nuclear@28 458 {
nuclear@28 459 KDNodeGPU *dest = kdbuf + idx;
nuclear@28 460
nuclear@28 461 dest->aabb = node->aabb;
nuclear@28 462 dest->num_faces = 0;
nuclear@28 463
nuclear@28 464 std::list<const Face*>::const_iterator it = node->faces.begin();
nuclear@28 465 while(it != node->faces.end()) {
nuclear@28 466 if(dest->num_faces >= (int)MAX_FACES) {
nuclear@28 467 fprintf(stderr, "kdtree_gpu_flatten WARNING: more than %d faces in node, skipping!\n", (int)MAX_FACES);
nuclear@28 468 break;
nuclear@28 469 }
nuclear@29 470 dest->face_idx[dest->num_faces++] = *it++ - facebuf;
nuclear@28 471 }
nuclear@28 472
nuclear@28 473 if(node->left) {
nuclear@28 474 assert(node->right);
nuclear@28 475 kdtree_gpu_flatten(kdbuf, idx * 2, node->left, facebuf);
nuclear@28 476 kdtree_gpu_flatten(kdbuf, idx * 2 + 1, node->right, facebuf);
nuclear@30 477 } else {
nuclear@30 478 dest->num_faces = -1;
nuclear@28 479 }
nuclear@28 480 }
nuclear@28 481
nuclear@27 482 static void print_item_counts(const KDNode *node, int level)
nuclear@27 483 {
nuclear@27 484 if(!node) return;
nuclear@27 485
nuclear@30 486 for(int i=0; i<level; i++) {
nuclear@27 487 fputs(" ", stdout);
nuclear@27 488 }
nuclear@30 489 printf("- %d (cost: %f)\n", node->num_faces, node->cost);
nuclear@27 490
nuclear@27 491 print_item_counts(node->left, level + 1);
nuclear@27 492 print_item_counts(node->right, level + 1);
nuclear@27 493 }