Pileus Git - grits/blob - src/grits-opengl.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:grits-opengl
  20  * @short_description: OpenGL based virtual globe
  21  *
  22  * #GritsOpenGL is the core rendering engine used by grits. Theoretically other
  23  * renderers could be writte, but they have not been. GritsOpenGL uses the ROAM
  24  * algorithm for updating surface mesh the planet. The only thing GritsOpenGL
  25  * can actually render on it's own is a wireframe of a sphere.
  26  *
  27  * GritsOpenGL requires (at least) OpenGL 2.0.
  28  */
  29
  30 #include <config.h>
  31 #include <math.h>
  32 #include <string.h>
  33 #include <gdk/gdkkeysyms.h>
  34 #include <gtk/gtk.h>
  35
  36 #include "grits-opengl.h"
  37 #include "grits-util.h"
  38 #include "gtkgl.h"
  39 #include "roam.h"
  40
  41 // #define ROAM_DEBUG
  42
  43 /* Tessellation, "finding intersecting triangles" */
  44 /* http://research.microsoft.com/pubs/70307/tr-2006-81.pdf */
  45 /* http://www.opengl.org/wiki/Alpha_Blending */
  46
  47 /* The unsorted/sroted GLists are blank head nodes,
  48  * This way us we can remove objects from the level just by fixing up links
  49  * I.e. we don't need to do a lookup to remove an object if we have its GList */
  50 struct RenderLevel {
  51         gint  num;
  52         GList unsorted;
  53         GList sorted;
  54 };
  55
  56 /***********
  57  * Helpers *
  58  ***********/
  59 static void _set_projection(GritsOpenGL *opengl)
  60 {
  61         double lat, lon, elev, rx, ry, rz;
  62         grits_viewer_get_location(GRITS_VIEWER(opengl), &lat, &lon, &elev);
  63         grits_viewer_get_rotation(GRITS_VIEWER(opengl), &rx, &ry, &rz);
  64
  65         /* Set projection and clipping planes */
  66         glMatrixMode(GL_PROJECTION);
  67         glLoadIdentity();
  68
  69         GtkAllocation alloc;
  70         gtk_widget_get_allocation(GTK_WIDGET(opengl), &alloc);
  71         double width  = alloc.width;
  72         double height = alloc.height;
  73         double ang    = atan((height/2)/FOV_DIST)*2;
  74         double atmos  = 100000;
  75         double near   = MAX(elev*0.75 - atmos, 50); // View 100km of atmosphere
  76         double far    = elev + 2*EARTH_R + atmos;   // on both sides of the earth
  77
  78         glViewport(0, 0, width, height);
  79         gluPerspective(rad2deg(ang), width/height, near, far);
  80
  81         /* Setup camera and lighting */
  82         glMatrixMode(GL_MODELVIEW);
  83         glLoadIdentity();
  84
  85         /* Camera 1 */
  86         glRotatef(rx, 1, 0, 0);
  87         glRotatef(rz, 0, 0, 1);
  88
  89         /* Lighting */
  90         float light_position[] = {-13*EARTH_R, 1*EARTH_R, 3*EARTH_R, 1.0f};
  91         glLightfv(GL_LIGHT0, GL_POSITION, light_position);
  92
  93         /* Camera 2 */
  94         glTranslatef(0, 0, -elev2rad(elev));
  95         glRotatef(lat, 1, 0, 0);
  96         glRotatef(-lon, 0, 1, 0);
  97
  98         /* Update roam view */
  99         g_mutex_lock(&opengl->sphere_lock);
 100         roam_sphere_update_view(opengl->sphere);
 101         g_mutex_unlock(&opengl->sphere_lock);
 102 }
 103
 104 static void _set_settings(GritsOpenGL *opengl)
 105 {
 106         glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 107         glEnable(GL_BLEND);
 108         glDisable(GL_ALPHA_TEST);
 109
 110         glEnable(GL_LIGHT0);
 111         glEnable(GL_LIGHTING);
 112
 113         glEnable(GL_LINE_SMOOTH);
 114
 115         glDisable(GL_TEXTURE_2D);
 116         glDisable(GL_COLOR_MATERIAL);
 117
 118         if (opengl->wireframe)
 119                 glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
 120         else
 121                 glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
 122
 123         /* Lighting */
 124 #ifdef ROAM_DEBUG
 125         float light_ambient[]  = {0.7f, 0.7f, 0.7f, 1.0f};
 126         float light_diffuse[]  = {2.0f, 2.0f, 2.0f, 1.0f};
 127 #else
 128         float light_ambient[]  = {0.2f, 0.2f, 0.2f, 1.0f};
 129         float light_diffuse[]  = {0.8f, 0.8f, 0.8f, 1.0f};
 130 #endif
 131         glLightfv(GL_LIGHT0, GL_AMBIENT,  light_ambient);
 132         glLightfv(GL_LIGHT0, GL_DIFFUSE,  light_diffuse);
 133
 134         /* Materials */
 135         float material_ambient[]  = {1.0, 1.0, 1.0, 1.0};
 136         float material_diffuse[]  = {1.0, 1.0, 1.0, 1.0};
 137         float material_specular[] = {0.0, 0.0, 0.0, 1.0};
 138         float material_emission[] = {0.0, 0.0, 0.0, 1.0};
 139         glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT,  material_ambient);
 140         glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE,  material_diffuse);
 141         glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, material_specular);
 142         glMaterialfv(GL_FRONT_AND_BACK, GL_EMISSION, material_emission);
 143
 144 #ifdef ROAM_DEBUG
 145         glColor4f(1.0, 1.0, 1.0, 1.0);
 146         glLineWidth(2);
 147 #else
 148         glCullFace(GL_BACK);
 149         glEnable(GL_CULL_FACE);
 150
 151         glClearDepth(1.0);
 152         glDepthFunc(GL_LEQUAL);
 153         glEnable(GL_DEPTH_TEST);
 154 #endif
 155 }
 156
 157 static GPtrArray *_objects_to_array(GritsOpenGL *opengl, gboolean ortho)
 158 {
 159         GPtrArray *array = g_ptr_array_new();
 160         for (GList *i = opengl->objects->head; i; i = i->next) {
 161                 struct RenderLevel *level = i->data;
 162                 if ((ortho == TRUE  && level->num <  GRITS_LEVEL_HUD) ||
 163                     (ortho == FALSE && level->num >= GRITS_LEVEL_HUD))
 164                         continue;
 165                 for (GList *j = level->unsorted.next; j; j = j->next)
 166                         g_ptr_array_add(array, j->data);
 167                 for (GList *j = level->sorted.next;   j; j = j->next)
 168                         g_ptr_array_add(array, j->data);
 169         }
 170         return array;
 171 }
 172
 173 /*************
 174  * Callbacks *
 175  *************/
 176
 177 static gint run_picking(GritsOpenGL *opengl, GdkEvent *event,
 178                 GPtrArray *objects, GritsObject **top)
 179 {
 180         /* Setup picking buffers */
 181         guint buffer[100][4] = {};
 182         glSelectBuffer(G_N_ELEMENTS(buffer), (guint*)buffer);
 183         if (!opengl->pickmode)
 184                 glRenderMode(GL_SELECT);
 185         glInitNames();
 186
 187         /* Render/pick objects */
 188         for (guint i = 0; i < objects->len; i++) {
 189                 glPushName(i);
 190                 GritsObject *object = objects->pdata[i];
 191                 object->state.picked = FALSE;
 192                 grits_object_pick(object, opengl);
 193                 glPopName();
 194         }
 195
 196         int hits = glRenderMode(GL_RENDER);
 197
 198         /* Process hits */
 199         for (int i = 0; i < hits; i++) {
 200                 //g_debug("\tHit: %d",     i);
 201                 //g_debug("\t\tcount: %d", buffer[i][0]);
 202                 //g_debug("\t\tz1:    %f", (float)buffer[i][1]/0x7fffffff);
 203                 //g_debug("\t\tz2:    %f", (float)buffer[i][2]/0x7fffffff);
 204                 //g_debug("\t\tname:  %p", (gpointer)buffer[i][3]);
 205                 guint        index  = buffer[i][3];
 206                 GritsObject *object = objects->pdata[index];
 207                 object->state.picked = TRUE;
 208                 *top = object;
 209         }
 210
 211         /* Notify objects of pointer movements */
 212         for (guint i = 0; i < objects->len; i++) {
 213                 GritsObject *object = objects->pdata[i];
 214                 grits_object_set_pointer(object, event, object->state.picked);
 215         }
 216
 217         return hits;
 218 }
 219
 220 static gboolean run_mouse_move(GritsOpenGL *opengl, GdkEventMotion *event)
 221 {
 222         GtkAllocation alloc;
 223         gtk_widget_get_allocation(GTK_WIDGET(opengl), &alloc);
 224
 225         gdouble gl_x   = event->x;
 226         gdouble gl_y   = alloc.height - event->y;
 227         gdouble delta  = opengl->pickmode ? 200 : 2;
 228
 229         if (opengl->pickmode) {
 230                 gtk_gl_begin(GTK_WIDGET(opengl));
 231                 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 232         }
 233
 234         /* Save matricies */
 235         gdouble projection[16];
 236         gint    viewport[4]; // x=0,y=0,w,h
 237         glGetDoublev(GL_PROJECTION_MATRIX, projection);
 238         glGetIntegerv(GL_VIEWPORT, viewport);
 239         glMatrixMode(GL_MODELVIEW);  glPushMatrix();
 240         glMatrixMode(GL_PROJECTION); glPushMatrix();
 241
 242         g_mutex_lock(&opengl->objects_lock);
 243
 244         GritsObject *top = NULL;
 245         GPtrArray *ortho = _objects_to_array(opengl, TRUE);
 246         GPtrArray *world = _objects_to_array(opengl, FALSE);
 247
 248         /* Run perspective picking */
 249         glMatrixMode(GL_PROJECTION); glLoadIdentity();
 250         gluPickMatrix(gl_x, gl_y, delta, delta, viewport);
 251         glMultMatrixd(projection);
 252         gint world_hits = run_picking(opengl, (GdkEvent*)event, world, &top);
 253
 254         /* Run ortho picking */
 255         glMatrixMode(GL_PROJECTION); glLoadIdentity();
 256         gluPickMatrix(gl_x, gl_y, delta, delta, viewport);
 257         glMatrixMode(GL_MODELVIEW);  glLoadIdentity();
 258         glOrtho(0, viewport[2], viewport[3], 0, 1000, -1000);
 259         gint ortho_hits = run_picking(opengl, (GdkEvent*)event, ortho, &top);
 260
 261         /* Update cursor */
 262         static GdkCursor *cursor = NULL;
 263         static GdkWindow *window = NULL;
 264         if (!window || !cursor) {
 265                 cursor = gdk_cursor_new(GDK_FLEUR);
 266                 window = gtk_widget_get_window(GTK_WIDGET(opengl));
 267         }
 268         GdkCursor *topcursor = top && top->cursor ? top->cursor : cursor;
 269         gdk_window_set_cursor(window, topcursor);
 270
 271         g_debug("GritsOpenGL: run_mouse_move - hits=%d/%d,%d/%d ev=%.0lf,%.0lf",
 272                         world_hits, world->len, ortho_hits, ortho->len, gl_x, gl_y);
 273
 274         g_ptr_array_free(world, TRUE);
 275         g_ptr_array_free(ortho, TRUE);
 276
 277         g_mutex_unlock(&opengl->objects_lock);
 278
 279         /* Test unproject */
 280         //gdouble lat, lon, elev;
 281         //grits_viewer_unproject(GRITS_VIEWER(opengl),
 282         //              gl_x, gl_y, -1, &lat, &lon, &elev);
 283
 284         /* Cleanup */
 285         glMatrixMode(GL_PROJECTION); glPopMatrix();
 286         glMatrixMode(GL_MODELVIEW);  glPopMatrix();
 287
 288         if (opengl->pickmode)
 289                 gtk_gl_end(GTK_WIDGET(opengl));
 290
 291         return FALSE;
 292 }
 293
 294 static gboolean on_motion_notify(GritsOpenGL *opengl, GdkEventMotion *event, gpointer _)
 295 {
 296         opengl->mouse_queue = *event;
 297         grits_viewer_queue_draw(GRITS_VIEWER(opengl));
 298         return FALSE;
 299 }
 300
 301 static void _draw_level(gpointer _level, gpointer _opengl)
 302 {
 303         GritsOpenGL *opengl = _opengl;
 304         struct RenderLevel *level = _level;
 305
 306         g_debug("GritsOpenGL: _draw_level - level=%-4d", level->num);
 307         int nsorted = 0, nunsorted = 0;
 308         GList *cur = NULL;
 309
 310         /* Configure individual levels */
 311         if (level->num < GRITS_LEVEL_WORLD) {
 312                 /* Disable depth for background levels */
 313                 glDepthMask(FALSE);
 314                 glDisable(GL_ALPHA_TEST);
 315         } else if (level->num < GRITS_LEVEL_OVERLAY) {
 316                 /* Enable depth and alpha for world levels */
 317                 glEnable(GL_ALPHA_TEST);
 318                 glAlphaFunc(GL_GREATER, 0.1);
 319         } else {
 320                 /* Disable depth for Overlay/HUD levels */
 321                 glDepthMask(FALSE);
 322         }
 323
 324         /* Start ortho */
 325         if (level->num >= GRITS_LEVEL_HUD) {
 326                 GtkAllocation alloc;
 327                 gtk_widget_get_allocation(GTK_WIDGET(opengl), &alloc);
 328                 glMatrixMode(GL_PROJECTION); glPushMatrix(); glLoadIdentity();
 329                 glMatrixMode(GL_MODELVIEW);  glPushMatrix(); glLoadIdentity();
 330                 glOrtho(0, alloc.width, alloc.height, 0, 1000, -1000);
 331         }
 332
 333         /* Draw unsorted objects without depth testing,
 334          * these are polygons, etc, rather than physical objects */
 335         glDisable(GL_DEPTH_TEST);
 336         for (cur = level->unsorted.next; cur; cur = cur->next, nunsorted++)
 337                 grits_object_draw(GRITS_OBJECT(cur->data), opengl);
 338
 339         /* Draw sorted objects using depth testing
 340          * These are things that are actually part of the world */
 341         glEnable(GL_DEPTH_TEST);
 342         for (cur = level->sorted.next; cur; cur = cur->next, nsorted++)
 343                 grits_object_draw(GRITS_OBJECT(cur->data), opengl);
 344
 345         /* End ortho */
 346         if (level->num >= GRITS_LEVEL_HUD) {
 347                 glMatrixMode(GL_PROJECTION); glPopMatrix();
 348                 glMatrixMode(GL_MODELVIEW);  glPopMatrix();
 349         }
 350
 351         /* Leave depth buffer write enabled */
 352         glDepthMask(TRUE);
 353
 354         /* TODO: Prune empty levels */
 355
 356         g_debug("GritsOpenGL: _draw_level - drew %d,%d objects",
 357                         nunsorted, nsorted);
 358 }
 359
 360 static gboolean on_draw(GritsOpenGL *opengl, void *cairo, gpointer _)
 361 {
 362         g_debug("GritsOpenGL: on_draw - begin");
 363
 364         if (opengl->pickmode)
 365                 return run_mouse_move(opengl, &(GdkEventMotion){});
 366
 367         if (opengl->mouse_queue.type != GDK_NOTHING) {
 368                 run_mouse_move(opengl, &opengl->mouse_queue);
 369                 opengl->mouse_queue.type = GDK_NOTHING;
 370         }
 371
 372         gtk_gl_begin(GTK_WIDGET(opengl));
 373
 374         _set_settings(opengl);
 375         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 376
 377 #ifndef ROAM_DEBUG
 378         g_mutex_lock(&opengl->sphere_lock);
 379         roam_sphere_update_errors(opengl->sphere);
 380         roam_sphere_split_merge(opengl->sphere);
 381         g_mutex_unlock(&opengl->sphere_lock);
 382 #endif
 383
 384 #ifdef ROAM_DEBUG
 385         roam_sphere_draw(opengl->sphere);
 386         roam_sphere_draw_normals(opengl->sphere);
 387         (void)_draw_level;
 388 #else
 389         g_mutex_lock(&opengl->objects_lock);
 390         g_queue_foreach(opengl->objects, _draw_level, opengl);
 391         g_mutex_unlock(&opengl->objects_lock);
 392 #endif
 393
 394         gtk_gl_end(GTK_WIDGET(opengl));
 395
 396         g_debug("GritsOpenGL: on_draw - end\n");
 397         return FALSE;
 398 }
 399
 400 static gboolean on_key_press(GritsOpenGL *opengl, GdkEventKey *event, gpointer _)
 401 {
 402         g_debug("GritsOpenGL: on_key_press - key=%x, state=%x, plus=%x",
 403                         event->keyval, event->state, GDK_KEY_plus);
 404
 405         guint kv = event->keyval;
 406         /* Testing */
 407         if (kv == GDK_KEY_w) {
 408                 opengl->wireframe = !opengl->wireframe;
 409                 grits_viewer_queue_draw(GRITS_VIEWER(opengl));
 410         }
 411         if (kv == GDK_KEY_p) {
 412                 opengl->pickmode = !opengl->pickmode;
 413                 grits_viewer_queue_draw(GRITS_VIEWER(opengl));
 414         }
 415 #ifdef ROAM_DEBUG
 416         else if (kv == GDK_KEY_n) roam_sphere_split_one(opengl->sphere);
 417         else if (kv == GDK_KEY_p) roam_sphere_merge_one(opengl->sphere);
 418         else if (kv == GDK_KEY_r) roam_sphere_split_merge(opengl->sphere);
 419         else if (kv == GDK_KEY_u) roam_sphere_update_errors(opengl->sphere);
 420         grits_viewer_queue_draw(GRITS_VIEWER(opengl));
 421 #endif
 422         return FALSE;
 423 }
 424
 425 static gboolean on_chained_event(GritsOpenGL *opengl, GdkEvent *event, gpointer _)
 426 {
 427         for (GList *i = opengl->objects->tail; i; i = i->prev) {
 428                 struct RenderLevel *level = i->data;
 429                 for (GList *j = level->unsorted.next; j; j = j->next)
 430                         if (grits_object_event(j->data, event))
 431                                 return TRUE;
 432                 for (GList *j = level->sorted.next;   j; j = j->next)
 433                         if (grits_object_event(j->data, event))
 434                                 return TRUE;
 435         }
 436         return FALSE;
 437 }
 438
 439 static void on_realize(GritsOpenGL *opengl, gpointer _)
 440 {
 441         g_debug("GritsOpenGL: on_realize");
 442         gtk_gl_begin(GTK_WIDGET(opengl));
 443
 444         /* Connect signals and idle functions now that opengl is fully initialized */
 445         gtk_widget_add_events(GTK_WIDGET(opengl), GDK_KEY_PRESS_MASK);
 446         g_signal_connect(opengl, "configure-event",  G_CALLBACK(_set_projection), NULL);
 447         g_signal_connect(opengl, "draw",             G_CALLBACK(on_draw),         NULL);
 448
 449         g_signal_connect(opengl, "key-press-event",  G_CALLBACK(on_key_press),    NULL);
 450
 451         g_signal_connect(opengl, "location-changed", G_CALLBACK(_set_projection), NULL);
 452         g_signal_connect(opengl, "rotation-changed", G_CALLBACK(_set_projection), NULL);
 453
 454         g_signal_connect(opengl, "motion-notify-event", G_CALLBACK(on_motion_notify), NULL);
 455         g_signal_connect_after(opengl, "key-press-event",      G_CALLBACK(on_chained_event), NULL);
 456         g_signal_connect_after(opengl, "key-release-event",    G_CALLBACK(on_chained_event), NULL);
 457         g_signal_connect_after(opengl, "button-press-event",   G_CALLBACK(on_chained_event), NULL);
 458         g_signal_connect_after(opengl, "button-release-event", G_CALLBACK(on_chained_event), NULL);
 459         g_signal_connect_after(opengl, "motion-notify-event",  G_CALLBACK(on_chained_event), NULL);
 460
 461         /* Re-queue resize incase configure was triggered before realize */
 462         gtk_widget_queue_resize(GTK_WIDGET(opengl));
 463 }
 464
 465 /*********************
 466  * GritsViewer methods *
 467  *********************/
 468 /**
 469  * grits_opengl_new:
 470  * @plugins: the plugins store to use
 471  * @prefs:   the preferences object to use
 472  *
 473  * Create a new OpenGL renderer.
 474  *
 475  * Returns: the new #GritsOpenGL
 476  */
 477 GritsViewer *grits_opengl_new(GritsPlugins *plugins, GritsPrefs *prefs)
 478 {
 479         g_debug("GritsOpenGL: new");
 480         GritsViewer *opengl = g_object_new(GRITS_TYPE_OPENGL, NULL);
 481         grits_viewer_setup(opengl, plugins, prefs);
 482         return opengl;
 483 }
 484
 485 static void grits_opengl_center_position(GritsViewer *_opengl, gdouble lat, gdouble lon, gdouble elev)
 486 {
 487         glRotatef(lon, 0, 1, 0);
 488         glRotatef(-lat, 1, 0, 0);
 489         glTranslatef(0, 0, elev2rad(elev));
 490 }
 491
 492 static void grits_opengl_project(GritsViewer *_opengl,
 493                 gdouble lat, gdouble lon, gdouble elev,
 494                 gdouble *px, gdouble *py, gdouble *pz)
 495 {
 496         GritsOpenGL *opengl = GRITS_OPENGL(_opengl);
 497         gdouble x, y, z;
 498         lle2xyz(lat, lon, elev, &x, &y, &z);
 499         gluProject(x, y, z,
 500                 opengl->sphere->view->model,
 501                 opengl->sphere->view->proj,
 502                 opengl->sphere->view->view,
 503                 px, py, pz);
 504 }
 505
 506 static void grits_opengl_unproject(GritsViewer *_opengl,
 507                 gdouble px, gdouble py, gdouble pz,
 508                 gdouble *lat, gdouble *lon, gdouble *elev)
 509 {
 510         GritsOpenGL *opengl = GRITS_OPENGL(_opengl);
 511         if (!opengl->sphere->view)
 512                 return;
 513         gdouble x, y, z;
 514         if (pz < 0) {
 515                 gfloat tmp = 0;
 516                 glReadPixels(px, py, 1, 1, GL_DEPTH_COMPONENT, GL_FLOAT, &tmp);
 517                 pz = tmp;
 518         }
 519         gluUnProject(px, py, pz,
 520                 opengl->sphere->view->model,
 521                 opengl->sphere->view->proj,
 522                 opengl->sphere->view->view,
 523                 &x, &y, &z);
 524         xyz2lle(x, y, z, lat, lon, elev);
 525         //g_message("GritsOpenGL: unproject - "
 526         //              "%4.0lf,%4.0lf,(%5.3lf) -> "
 527         //              "%8.0lf,%8.0lf,%8.0lf -> "
 528         //              "%6.2lf,%7.2lf,%4.0lf",
 529         //      px, py, pz, x, y, z, *lat, *lon, *elev);
 530 }
 531
 532 static void grits_opengl_set_height_func(GritsViewer *_opengl, GritsBounds *bounds,
 533                 RoamHeightFunc height_func, gpointer user_data, gboolean update)
 534 {
 535         GritsOpenGL *opengl = GRITS_OPENGL(_opengl);
 536         /* TODO: get points? */
 537         g_mutex_lock(&opengl->sphere_lock);
 538         GList *triangles = roam_sphere_get_intersect(opengl->sphere, TRUE,
 539                         bounds->n, bounds->s, bounds->e, bounds->w);
 540         for (GList *cur = triangles; cur; cur = cur->next) {
 541                 RoamTriangle *tri = cur->data;
 542                 RoamPoint *points[] = {tri->p.l, tri->p.m, tri->p.r, tri->split};
 543                 for (int i = 0; i < G_N_ELEMENTS(points); i++) {
 544                         if (bounds->n >= points[i]->lat && points[i]->lat >= bounds->s &&
 545                             bounds->e >= points[i]->lon && points[i]->lon >= bounds->w) {
 546                                 points[i]->height_func = height_func;
 547                                 points[i]->height_data = user_data;
 548                                 roam_point_update_height(points[i]);
 549                         }
 550                 }
 551         }
 552         g_list_free(triangles);
 553         g_mutex_unlock(&opengl->sphere_lock);
 554 }
 555
 556 static void _grits_opengl_clear_height_func_rec(RoamTriangle *root)
 557 {
 558         if (!root)
 559                 return;
 560         RoamPoint *points[] = {root->p.l, root->p.m, root->p.r, root->split};
 561         for (int i = 0; i < G_N_ELEMENTS(points); i++) {
 562                 points[i]->height_func = NULL;
 563                 points[i]->height_data = NULL;
 564                 roam_point_update_height(points[i]);
 565         }
 566         _grits_opengl_clear_height_func_rec(root->kids[0]);
 567         _grits_opengl_clear_height_func_rec(root->kids[1]);
 568 }
 569
 570 static void grits_opengl_clear_height_func(GritsViewer *_opengl)
 571 {
 572         GritsOpenGL *opengl = GRITS_OPENGL(_opengl);
 573         for (int i = 0; i < G_N_ELEMENTS(opengl->sphere->roots); i++)
 574                 _grits_opengl_clear_height_func_rec(opengl->sphere->roots[i]);
 575 }
 576
 577 static gint _objects_find(gconstpointer a, gconstpointer b)
 578 {
 579         const struct RenderLevel *level = a;
 580         const gint *key = b;
 581         return level->num == *key ? 0 : 1;
 582 }
 583
 584 static gint _objects_sort(gconstpointer _a, gconstpointer _b, gpointer _)
 585 {
 586         const struct RenderLevel *a = _a;
 587         const struct RenderLevel *b = _b;
 588         return a->num < b->num ? -1 :
 589                a->num > b->num ?  1 : 0;
 590 }
 591
 592 static void _objects_free(gpointer value, gpointer _)
 593 {
 594         struct RenderLevel *level = value;
 595         if (level->sorted.next)
 596                 g_list_free_full(level->sorted.next, g_object_unref);
 597         if (level->unsorted.next)
 598                 g_list_free_full(level->unsorted.next, g_object_unref);
 599         g_free(level);
 600 }
 601
 602 static void grits_opengl_add(GritsViewer *_opengl, GritsObject *object,
 603                 gint num, gboolean sort)
 604 {
 605         g_assert(GRITS_IS_OPENGL(_opengl));
 606         GritsOpenGL *opengl = GRITS_OPENGL(_opengl);
 607         g_mutex_lock(&opengl->objects_lock);
 608         struct RenderLevel *level = NULL;
 609         GList *tmp = g_queue_find_custom(opengl->objects, &num, _objects_find);
 610         if (tmp) {
 611                 level = tmp->data;
 612         } else {
 613                 level = g_new0(struct RenderLevel, 1);
 614                 level->num = num;
 615                 g_queue_insert_sorted(opengl->objects, level, _objects_sort, NULL);
 616         }
 617         GList *list = sort ? &level->sorted : &level->unsorted;
 618         /* Put the link in the list */
 619         GList *link = g_new0(GList, 1);
 620         link->data = object;
 621         link->prev = list;
 622         link->next = list->next;
 623         if (list->next)
 624                 list->next->prev = link;
 625         list->next = link;
 626         object->ref = link;
 627         g_object_ref(object);
 628         g_mutex_unlock(&opengl->objects_lock);
 629 }
 630
 631 void grits_opengl_remove(GritsViewer *_opengl, GritsObject *object)
 632 {
 633         g_assert(GRITS_IS_OPENGL(_opengl));
 634         GritsOpenGL *opengl = GRITS_OPENGL(_opengl);
 635         if (!object->ref)
 636                 return;
 637         g_mutex_lock(&opengl->objects_lock);
 638         GList *link = object->ref;
 639         /* Just unlink and free it, link->prev is assured */
 640         link->prev->next = link->next;
 641         if (link->next)
 642                 link->next->prev = link->prev;
 643         g_free(link);
 644         object->ref = NULL;
 645         g_object_unref(object);
 646         g_mutex_unlock(&opengl->objects_lock);
 647 }
 648
 649 /****************
 650  * GObject code *
 651  ****************/
 652 G_DEFINE_TYPE(GritsOpenGL, grits_opengl, GRITS_TYPE_VIEWER);
 653 static void grits_opengl_init(GritsOpenGL *opengl)
 654 {
 655         g_debug("GritsOpenGL: init");
 656         opengl->objects = g_queue_new();
 657         opengl->sphere  = roam_sphere_new(opengl);
 658         g_mutex_init(&opengl->objects_lock);
 659         g_mutex_init(&opengl->sphere_lock);
 660         gtk_gl_enable(GTK_WIDGET(opengl));
 661         gtk_widget_add_events(GTK_WIDGET(opengl), GDK_KEY_PRESS_MASK);
 662         g_signal_connect(opengl, "map", G_CALLBACK(on_realize), NULL);
 663 }
 664 static void grits_opengl_dispose(GObject *_opengl)
 665 {
 666         g_debug("GritsOpenGL: dispose");
 667         GritsOpenGL *opengl = GRITS_OPENGL(_opengl);
 668         if (opengl->objects) {
 669                 GQueue *objects = opengl->objects;;
 670                 opengl->objects = NULL;
 671                 g_mutex_lock(&opengl->objects_lock);
 672                 g_queue_foreach(objects, _objects_free, NULL);
 673                 g_queue_free(objects);
 674                 g_mutex_unlock(&opengl->objects_lock);
 675         }
 676         G_OBJECT_CLASS(grits_opengl_parent_class)->dispose(_opengl);
 677 }
 678 static void grits_opengl_finalize(GObject *_opengl)
 679 {
 680         g_debug("GritsOpenGL: finalize");
 681         GritsOpenGL *opengl = GRITS_OPENGL(_opengl);
 682         roam_sphere_free(opengl->sphere);
 683         g_mutex_clear(&opengl->objects_lock);
 684         g_mutex_clear(&opengl->sphere_lock);
 685         gtk_gl_disable(GTK_WIDGET(opengl));
 686         G_OBJECT_CLASS(grits_opengl_parent_class)->finalize(_opengl);
 687 }
 688 static void grits_opengl_class_init(GritsOpenGLClass *klass)
 689 {
 690         g_debug("GritsOpenGL: class_init");
 691         GObjectClass *gobject_class = G_OBJECT_CLASS(klass);
 692         gobject_class->finalize = grits_opengl_finalize;
 693         gobject_class->dispose = grits_opengl_dispose;
 694
 695         GritsViewerClass *viewer_class = GRITS_VIEWER_CLASS(klass);
 696         viewer_class->center_position   = grits_opengl_center_position;
 697         viewer_class->project           = grits_opengl_project;
 698         viewer_class->unproject         = grits_opengl_unproject;
 699         viewer_class->clear_height_func = grits_opengl_clear_height_func;
 700         viewer_class->set_height_func   = grits_opengl_set_height_func;
 701         viewer_class->add               = grits_opengl_add;
 702         viewer_class->remove            = grits_opengl_remove;
 703 }