Pileus Git - grits/blob - src/grits-opengl.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: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 relies on #GtkGlExt and 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 #include <gtk/gtkgl.h>
  36 #include <GL/gl.h>
  37 #include <GL/glu.h>
  38
  39 #include "grits-opengl.h"
  40 #include "grits-util.h"
  41 #include "roam.h"
  42
  43 // #define ROAM_DEBUG
  44
  45 /* Tessellation, "finding intersecting triangles" */
  46 /* http://research.microsoft.com/pubs/70307/tr-2006-81.pdf */
  47 /* http://www.opengl.org/wiki/Alpha_Blending */
  48
  49 /***********
  50  * Helpers *
  51  ***********/
  52 static void _set_visuals(GritsOpenGL *opengl)
  53 {
  54         glMatrixMode(GL_MODELVIEW);
  55         glLoadIdentity();
  56
  57         /* Camera 1 */
  58         double lat, lon, elev, rx, ry, rz;
  59         grits_viewer_get_location(GRITS_VIEWER(opengl), &lat, &lon, &elev);
  60         grits_viewer_get_rotation(GRITS_VIEWER(opengl), &rx, &ry, &rz);
  61         glRotatef(rx, 1, 0, 0);
  62         glRotatef(rz, 0, 0, 1);
  63
  64         /* Lighting */
  65 #ifdef ROAM_DEBUG
  66         float light_ambient[]  = {0.7f, 0.7f, 0.7f, 1.0f};
  67         float light_diffuse[]  = {2.0f, 2.0f, 2.0f, 1.0f};
  68 #else
  69         float light_ambient[]  = {0.2f, 0.2f, 0.2f, 1.0f};
  70         float light_diffuse[]  = {0.8f, 0.8f, 0.8f, 1.0f};
  71 #endif
  72         float light_position[] = {-13*EARTH_R, 1*EARTH_R, 3*EARTH_R, 1.0f};
  73         glLightfv(GL_LIGHT0, GL_AMBIENT,  light_ambient);
  74         glLightfv(GL_LIGHT0, GL_DIFFUSE,  light_diffuse);
  75         glLightfv(GL_LIGHT0, GL_POSITION, light_position);
  76         glEnable(GL_LIGHT0);
  77         glEnable(GL_LIGHTING);
  78
  79         float material_ambient[]  = {1.0, 1.0, 1.0, 1.0};
  80         float material_diffuse[]  = {1.0, 1.0, 1.0, 1.0};
  81         float material_specular[] = {0.0, 0.0, 0.0, 1.0};
  82         float material_emission[] = {0.0, 0.0, 0.0, 1.0};
  83         glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT,  material_ambient);
  84         glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE,  material_diffuse);
  85         glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, material_specular);
  86         glMaterialfv(GL_FRONT_AND_BACK, GL_EMISSION, material_emission);
  87         glDisable(GL_TEXTURE_2D);
  88         glDisable(GL_COLOR_MATERIAL);
  89
  90         /* Camera 2 */
  91         glTranslatef(0, 0, -elev2rad(elev));
  92         glRotatef(lat, 1, 0, 0);
  93         glRotatef(-lon, 0, 1, 0);
  94
  95         glDisable(GL_ALPHA_TEST);
  96
  97         glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
  98         glEnable(GL_BLEND);
  99
 100 #ifndef ROAM_DEBUG
 101         glCullFace(GL_BACK);
 102         glEnable(GL_CULL_FACE);
 103
 104         glClearDepth(1.0);
 105         glDepthFunc(GL_LEQUAL);
 106         glEnable(GL_DEPTH_TEST);
 107 #endif
 108
 109         glEnable(GL_LINE_SMOOTH);
 110
 111         glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
 112         //glShadeModel(GL_FLAT);
 113
 114         g_mutex_lock(opengl->sphere_lock);
 115         roam_sphere_update_view(opengl->sphere);
 116         g_mutex_unlock(opengl->sphere_lock);
 117 }
 118
 119
 120 /*************
 121  * Callbacks *
 122  *************/
 123 /* The unsorted/sroted GLists are blank head nodes,
 124  * This way us we can remove objects from the level just by fixing up links
 125  * I.e. we don't need to do a lookup to remove an object if we have its GList */
 126 struct RenderLevel {
 127         GList unsorted;
 128         GList sorted;
 129 };
 130
 131 static gboolean on_configure(GritsOpenGL *opengl, GdkEventConfigure *event, gpointer _)
 132 {
 133         g_debug("GritsOpenGL: on_configure");
 134
 135         double width  = GTK_WIDGET(opengl)->allocation.width;
 136         double height = GTK_WIDGET(opengl)->allocation.height;
 137
 138         /* Setup OpenGL Window */
 139         glViewport(0, 0, width, height);
 140         glMatrixMode(GL_PROJECTION);
 141         glLoadIdentity();
 142         double ang = atan(height/FOV_DIST);
 143         gluPerspective(rad2deg(ang)*2, width/height, 1000, 10*EARTH_R);
 144
 145 #ifndef ROAM_DEBUG
 146         g_mutex_lock(opengl->sphere_lock);
 147         roam_sphere_update_errors(opengl->sphere);
 148         g_mutex_unlock(opengl->sphere_lock);
 149 #endif
 150
 151         return FALSE;
 152 }
 153
 154 static gboolean _draw_level(gpointer key, gpointer value, gpointer user_data)
 155 {
 156         g_debug("GritsOpenGL: _draw_level - level=%-4d", (int)key);
 157         GritsOpenGL *opengl = user_data;
 158         struct RenderLevel *level = value;
 159         int nsorted = 0, nunsorted = 0;
 160         GList *cur = NULL;
 161
 162         /* Draw opaque objects without sorting */
 163         glDepthMask(TRUE);
 164         glClear(GL_DEPTH_BUFFER_BIT);
 165         for (cur = level->unsorted.next; cur; cur = cur->next, nunsorted++)
 166                 grits_object_draw(GRITS_OBJECT(cur->data), opengl);
 167
 168         /* Freeze depth buffer and draw transparent objects sorted */
 169         /* TODO: sorting */
 170         //glDepthMask(FALSE);
 171         glAlphaFunc(GL_GREATER, 0.1);
 172         for (cur = level->sorted.next; cur; cur = cur->next, nsorted++)
 173                 grits_object_draw(GRITS_OBJECT(cur->data), opengl);
 174
 175         /* TODO: Prune empty levels */
 176
 177         g_debug("GritsOpenGL: _draw_level - drew %d,%d objects",
 178                         nunsorted, nsorted);
 179         return FALSE;
 180 }
 181
 182 static gboolean on_expose(GritsOpenGL *opengl, GdkEventExpose *event, gpointer _)
 183 {
 184         g_debug("GritsOpenGL: on_expose - begin");
 185
 186         glClear(GL_COLOR_BUFFER_BIT);
 187
 188         _set_visuals(opengl);
 189 #ifdef ROAM_DEBUG
 190         glColor4f(1.0, 1.0, 1.0, 1.0);
 191         glLineWidth(2);
 192         glDisable(GL_TEXTURE_2D);
 193         glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
 194         roam_sphere_draw(opengl->sphere);
 195         (void)_draw_level;
 196         //roam_sphere_draw_normals(opengl->sphere);
 197 #else
 198         g_mutex_lock(opengl->objects_lock);
 199         g_tree_foreach(opengl->objects, _draw_level, opengl);
 200         if (opengl->wireframe) {
 201                 glClear(GL_DEPTH_BUFFER_BIT);
 202                 glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
 203                 roam_sphere_draw(opengl->sphere);
 204                 g_tree_foreach(opengl->objects, _draw_level, opengl);
 205         }
 206         g_mutex_unlock(opengl->objects_lock);
 207 #endif
 208
 209         GdkGLDrawable *gldrawable = gtk_widget_get_gl_drawable(GTK_WIDGET(opengl));
 210         gdk_gl_drawable_swap_buffers(gldrawable);
 211
 212         g_debug("GritsOpenGL: on_expose - end\n");
 213         return FALSE;
 214 }
 215
 216 static gboolean on_key_press(GritsOpenGL *opengl, GdkEventKey *event, gpointer _)
 217 {
 218         g_debug("GritsOpenGL: on_key_press - key=%x, state=%x, plus=%x",
 219                         event->keyval, event->state, GDK_plus);
 220
 221         guint kv = event->keyval;
 222         /* Testing */
 223         if (kv == GDK_w) {
 224                 opengl->wireframe = !opengl->wireframe;
 225                 gtk_widget_queue_draw(GTK_WIDGET(opengl));
 226         }
 227 #ifdef ROAM_DEBUG
 228         else if (kv == GDK_n) roam_sphere_split_one(opengl->sphere);
 229         else if (kv == GDK_p) roam_sphere_merge_one(opengl->sphere);
 230         else if (kv == GDK_r) roam_sphere_split_merge(opengl->sphere);
 231         else if (kv == GDK_u) roam_sphere_update_errors(opengl->sphere);
 232         gtk_widget_queue_draw(GTK_WIDGET(opengl));
 233 #endif
 234         return FALSE;
 235 }
 236
 237 static gboolean _update_errors_cb(gpointer _opengl)
 238 {
 239         GritsOpenGL *opengl = _opengl;
 240         g_mutex_lock(opengl->sphere_lock);
 241         roam_sphere_update_errors(opengl->sphere);
 242         g_mutex_unlock(opengl->sphere_lock);
 243         opengl->ue_source = 0;
 244         return FALSE;
 245 }
 246 static void on_view_changed(GritsOpenGL *opengl,
 247                 gdouble _1, gdouble _2, gdouble _3)
 248 {
 249         g_debug("GritsOpenGL: on_view_changed");
 250         _set_visuals(opengl);
 251 #ifndef ROAM_DEBUG
 252         if (!opengl->ue_source)
 253                 opengl->ue_source = g_idle_add_full(G_PRIORITY_HIGH_IDLE+30,
 254                                 _update_errors_cb, opengl, NULL);
 255         //roam_sphere_update_errors(opengl->sphere);
 256 #else
 257         (void)_update_errors_cb;
 258 #endif
 259 }
 260
 261 static gboolean on_idle(GritsOpenGL *opengl)
 262 {
 263         //g_debug("GritsOpenGL: on_idle");
 264         g_mutex_lock(opengl->sphere_lock);
 265         if (roam_sphere_split_merge(opengl->sphere))
 266                 gtk_widget_queue_draw(GTK_WIDGET(opengl));
 267         g_mutex_unlock(opengl->sphere_lock);
 268         return TRUE;
 269 }
 270
 271 static void on_realize(GritsOpenGL *opengl, gpointer _)
 272 {
 273         g_debug("GritsOpenGL: on_realize");
 274
 275         /* Start OpenGL */
 276         GdkGLContext   *glcontext  = gtk_widget_get_gl_context(GTK_WIDGET(opengl));
 277         GdkGLDrawable  *gldrawable = gtk_widget_get_gl_drawable(GTK_WIDGET(opengl));
 278         if (!gdk_gl_drawable_gl_begin(gldrawable, glcontext))
 279                 g_assert_not_reached();
 280
 281         /* Connect signals and idle functions now that opengl is fully initialized */
 282         gtk_widget_add_events(GTK_WIDGET(opengl), GDK_KEY_PRESS_MASK);
 283         g_signal_connect(opengl, "configure-event",  G_CALLBACK(on_configure),    NULL);
 284         g_signal_connect(opengl, "expose-event",     G_CALLBACK(on_expose),       NULL);
 285
 286         g_signal_connect(opengl, "key-press-event",  G_CALLBACK(on_key_press),    NULL);
 287
 288         g_signal_connect(opengl, "location-changed", G_CALLBACK(on_view_changed), NULL);
 289         g_signal_connect(opengl, "rotation-changed", G_CALLBACK(on_view_changed), NULL);
 290
 291 #ifndef ROAM_DEBUG
 292         opengl->sm_source[0] = g_timeout_add_full(G_PRIORITY_HIGH_IDLE+30, 33,  (GSourceFunc)on_idle, opengl, NULL);
 293         opengl->sm_source[1] = g_timeout_add_full(G_PRIORITY_HIGH_IDLE+10, 500, (GSourceFunc)on_idle, opengl, NULL);
 294 #else
 295         (void)on_idle;
 296         (void)_update_errors_cb;
 297 #endif
 298
 299         /* Re-queue resize incase configure was triggered before realize */
 300         gtk_widget_queue_resize(GTK_WIDGET(opengl));
 301 }
 302
 303 /*********************
 304  * GritsViewer methods *
 305  *********************/
 306 /**
 307  * grits_opengl_new:
 308  * @plugins: the plugins store to use
 309  * @prefs:   the preferences object to use
 310  *
 311  * Create a new OpenGL renderer.
 312  *
 313  * Returns: the new #GritsOpenGL
 314  */
 315 GritsViewer *grits_opengl_new(GritsPlugins *plugins, GritsPrefs *prefs)
 316 {
 317         g_debug("GritsOpenGL: new");
 318         GritsViewer *opengl = g_object_new(GRITS_TYPE_OPENGL, NULL);
 319         grits_viewer_setup(opengl, plugins, prefs);
 320         return opengl;
 321 }
 322
 323 static void grits_opengl_center_position(GritsViewer *_opengl, gdouble lat, gdouble lon, gdouble elev)
 324 {
 325         glRotatef(lon, 0, 1, 0);
 326         glRotatef(-lat, 1, 0, 0);
 327         glTranslatef(0, 0, elev2rad(elev));
 328 }
 329
 330 static void grits_opengl_project(GritsViewer *_opengl,
 331                 gdouble lat, gdouble lon, gdouble elev,
 332                 gdouble *px, gdouble *py, gdouble *pz)
 333 {
 334         GritsOpenGL *opengl = GRITS_OPENGL(_opengl);
 335         gdouble x, y, z;
 336         lle2xyz(lat, lon, elev, &x, &y, &z);
 337         gluProject(x, y, z,
 338                 opengl->sphere->view->model,
 339                 opengl->sphere->view->proj,
 340                 opengl->sphere->view->view,
 341                 px, py, pz);
 342 }
 343
 344 static void grits_opengl_set_height_func(GritsViewer *_opengl, GritsBounds *bounds,
 345                 RoamHeightFunc height_func, gpointer user_data, gboolean update)
 346 {
 347         GritsOpenGL *opengl = GRITS_OPENGL(_opengl);
 348         /* TODO: get points? */
 349         g_mutex_lock(opengl->sphere_lock);
 350         GList *triangles = roam_sphere_get_intersect(opengl->sphere, TRUE,
 351                         bounds->n, bounds->s, bounds->e, bounds->w);
 352         for (GList *cur = triangles; cur; cur = cur->next) {
 353                 RoamTriangle *tri = cur->data;
 354                 RoamPoint *points[] = {tri->p.l, tri->p.m, tri->p.r, tri->split};
 355                 for (int i = 0; i < G_N_ELEMENTS(points); i++) {
 356                         if (bounds->n >= points[i]->lat && points[i]->lat >= bounds->s &&
 357                             bounds->e >= points[i]->lon && points[i]->lon >= bounds->w) {
 358                                 points[i]->height_func = height_func;
 359                                 points[i]->height_data = user_data;
 360                                 roam_point_update_height(points[i]);
 361                         }
 362                 }
 363         }
 364         g_list_free(triangles);
 365         g_mutex_unlock(opengl->sphere_lock);
 366 }
 367
 368 static void _grits_opengl_clear_height_func_rec(RoamTriangle *root)
 369 {
 370         if (!root)
 371                 return;
 372         RoamPoint *points[] = {root->p.l, root->p.m, root->p.r, root->split};
 373         for (int i = 0; i < G_N_ELEMENTS(points); i++) {
 374                 points[i]->height_func = NULL;
 375                 points[i]->height_data = NULL;
 376                 roam_point_update_height(points[i]);
 377         }
 378         _grits_opengl_clear_height_func_rec(root->kids[0]);
 379         _grits_opengl_clear_height_func_rec(root->kids[1]);
 380 }
 381
 382 static void grits_opengl_clear_height_func(GritsViewer *_opengl)
 383 {
 384         GritsOpenGL *opengl = GRITS_OPENGL(_opengl);
 385         for (int i = 0; i < G_N_ELEMENTS(opengl->sphere->roots); i++)
 386                 _grits_opengl_clear_height_func_rec(opengl->sphere->roots[i]);
 387 }
 388
 389 static gpointer grits_opengl_add(GritsViewer *_opengl, GritsObject *object,
 390                 gint key, gboolean sort)
 391 {
 392         g_assert(GRITS_IS_OPENGL(_opengl));
 393         GritsOpenGL *opengl = GRITS_OPENGL(_opengl);
 394         g_mutex_lock(opengl->objects_lock);
 395         struct RenderLevel *level = g_tree_lookup(opengl->objects, (gpointer)key);
 396         if (!level) {
 397                 level = g_new0(struct RenderLevel, 1);
 398                 g_tree_insert(opengl->objects, (gpointer)key, level);
 399         }
 400         GList *list = sort ? &level->sorted : &level->unsorted;
 401         /* Put the link in the list */
 402         GList *link = g_new0(GList, 1);
 403         link->data = object;
 404         link->prev = list;
 405         link->next = list->next;
 406         if (list->next)
 407                 list->next->prev = link;
 408         list->next = link;
 409         g_mutex_unlock(opengl->objects_lock);
 410         return link;
 411 }
 412
 413 static GritsObject *grits_opengl_remove(GritsViewer *_opengl, gpointer _link)
 414 {
 415         g_assert(GRITS_IS_OPENGL(_opengl));
 416         GritsOpenGL *opengl = GRITS_OPENGL(_opengl);
 417         GList *link = _link;
 418         g_mutex_lock(opengl->objects_lock);
 419         GritsObject *object = link->data;
 420         /* Just unlink and free it, link->prev is assured */
 421         link->prev->next = link->next;
 422         if (link->next)
 423                 link->next->prev = link->prev;
 424         g_mutex_unlock(opengl->objects_lock);
 425         g_free(link);
 426         g_object_unref(object);
 427         return object;
 428 }
 429
 430 /****************
 431  * GObject code *
 432  ****************/
 433 static int _objects_cmp(gconstpointer _a, gconstpointer _b, gpointer _)
 434 {
 435         gint a = (int)_a, b = (int)_b;
 436         return a < b ? -1 :
 437                a > b ?  1 : 0;
 438 }
 439 static void _objects_free(gpointer value)
 440 {
 441         struct RenderLevel *level = value;
 442         if (level->sorted.next)
 443                 g_list_free(level->sorted.next);
 444         if (level->unsorted.next)
 445                 g_list_free(level->unsorted.next);
 446         g_free(level);
 447 }
 448
 449 G_DEFINE_TYPE(GritsOpenGL, grits_opengl, GRITS_TYPE_VIEWER);
 450 static void grits_opengl_init(GritsOpenGL *opengl)
 451 {
 452         g_debug("GritsOpenGL: init");
 453         opengl->objects      = g_tree_new_full(_objects_cmp, NULL, NULL, _objects_free);
 454         opengl->objects_lock = g_mutex_new();
 455         opengl->sphere       = roam_sphere_new(opengl);
 456         opengl->sphere_lock  = g_mutex_new();
 457
 458         /* Set OpenGL before "realize" */
 459         GdkGLConfig *glconfig = gdk_gl_config_new_by_mode(
 460                         GDK_GL_MODE_RGBA   | GDK_GL_MODE_DEPTH |
 461                         GDK_GL_MODE_DOUBLE | GDK_GL_MODE_ALPHA);
 462         if (!glconfig)
 463                 g_error("Failed to create glconfig");
 464         if (!gtk_widget_set_gl_capability(GTK_WIDGET(opengl),
 465                                 glconfig, NULL, TRUE, GDK_GL_RGBA_TYPE))
 466                 g_error("GL lacks required capabilities");
 467         g_object_unref(glconfig);
 468
 469         /* Finish OpenGL init after it's realized */
 470         g_signal_connect(opengl, "realize", G_CALLBACK(on_realize), NULL);
 471 }
 472 static void grits_opengl_dispose(GObject *_opengl)
 473 {
 474         g_debug("GritsOpenGL: dispose");
 475         GritsOpenGL *opengl = GRITS_OPENGL(_opengl);
 476         if (opengl->sm_source[0]) {
 477                 g_source_remove(opengl->sm_source[0]);
 478                 opengl->sm_source[0] = 0;
 479         }
 480         if (opengl->sm_source[1]) {
 481                 g_source_remove(opengl->sm_source[1]);
 482                 opengl->sm_source[1] = 0;
 483         }
 484         if (opengl->ue_source) {
 485                 g_source_remove(opengl->ue_source);
 486                 opengl->ue_source = 0;
 487         }
 488         G_OBJECT_CLASS(grits_opengl_parent_class)->dispose(_opengl);
 489 }
 490 static void grits_opengl_finalize(GObject *_opengl)
 491 {
 492         g_debug("GritsOpenGL: finalize");
 493         GritsOpenGL *opengl = GRITS_OPENGL(_opengl);
 494         roam_sphere_free(opengl->sphere);
 495         g_tree_destroy(opengl->objects);
 496         g_mutex_free(opengl->objects_lock);
 497         g_mutex_free(opengl->sphere_lock);
 498         G_OBJECT_CLASS(grits_opengl_parent_class)->finalize(_opengl);
 499 }
 500 static void grits_opengl_class_init(GritsOpenGLClass *klass)
 501 {
 502         g_debug("GritsOpenGL: class_init");
 503         GObjectClass *gobject_class = G_OBJECT_CLASS(klass);
 504         gobject_class->finalize = grits_opengl_finalize;
 505         gobject_class->dispose = grits_opengl_dispose;
 506
 507         GritsViewerClass *viewer_class = GRITS_VIEWER_CLASS(klass);
 508         viewer_class->center_position   = grits_opengl_center_position;
 509         viewer_class->project           = grits_opengl_project;
 510         viewer_class->clear_height_func = grits_opengl_clear_height_func;
 511         viewer_class->set_height_func   = grits_opengl_set_height_func;
 512         viewer_class->add               = grits_opengl_add;
 513         viewer_class->remove            = grits_opengl_remove;
 514 }