Pileus Git - grits/blob - src/objects/grits-object.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-object
  20  * @short_description: Base class for drawing operations
  21  *
  22  * Objects in grits are things which can be added to the viewer and will be
  23  * displayed to the user. Each object has information such as it's location and
  24  * level of detail which are used by the viewer to determine which objects
  25  * should be drawn.
  26  *
  27  * Each #GritsObject is also a #GObject, but not every GObject in grits is a
  28  * GritsObject. The "Object" part of the name is just coincidence.
  29  */
  30
  31 #include <config.h>
  32 #include <math.h>
  33 #include <GL/gl.h>
  34
  35 #include "grits-object.h"
  36
  37 /* Constants */
  38 enum {
  39         SIG_ENTER,
  40         SIG_LEAVE,
  41         NUM_SIGNALS,
  42 };
  43 static guint signals[NUM_SIGNALS];
  44
  45 void grits_object_pickdraw(GritsObject *object, GritsOpenGL *opengl, gboolean pick)
  46 {
  47         GritsObjectClass *klass = GRITS_OBJECT_GET_CLASS(object);
  48         if (!klass->draw) {
  49                 g_warning("GritsObject: draw - Unimplemented");
  50                 return;
  51         }
  52
  53         /* Skip hidden objects */
  54         if (object->hidden)
  55                 return;
  56
  57         /* Support GritsTester */
  58         if (!GRITS_IS_OPENGL(opengl)) {
  59                 g_debug("GritsObject: draw - drawing raw object");
  60                 klass->draw(object, opengl);
  61                 return;
  62         }
  63
  64         /* Calculae distance for LOD and horizon tests */
  65         GritsPoint *center = &object->center;
  66         if ((!(object->skip & GRITS_SKIP_LOD) ||
  67              !(object->skip & GRITS_SKIP_HORIZON)) &&
  68             (center->elev != -EARTH_R)) {
  69                 /* LOD test */
  70                 gdouble eye[3], obj[3];
  71                 grits_viewer_get_location(GRITS_VIEWER(opengl),
  72                                 &eye[0], &eye[1], &eye[2]);
  73                 gdouble elev = eye[2];
  74                 lle2xyz(eye[0], eye[1], eye[2],
  75                                 &eye[0], &eye[1], &eye[2]);
  76                 lle2xyz(center->lat, center->lon, center->elev,
  77                                 &obj[0], &obj[1], &obj[2]);
  78                 gdouble dist = distd(obj, eye);
  79
  80                 /* Level of detail test */
  81                 if (!(object->skip & GRITS_SKIP_LOD)
  82                                 && object->lod > 0) {
  83                         if (object->lod < dist)
  84                                 return;
  85                 }
  86
  87                 /* Horizon test */
  88                 if (!(object->skip & GRITS_SKIP_HORIZON)) {
  89                         gdouble c = EARTH_R+elev;
  90                         gdouble a = EARTH_R;
  91                         gdouble horizon = sqrt(c*c - a*a);
  92                         if (dist > horizon)
  93                                 return;
  94                 }
  95         }
  96
  97         /* Save state, draw, restore state */
  98         g_mutex_lock(opengl->sphere_lock);
  99         if (!(object->skip & GRITS_SKIP_STATE)) {
 100                 glPushAttrib(GL_ALL_ATTRIB_BITS);
 101                 glMatrixMode(GL_PROJECTION); glPushMatrix();
 102                 glMatrixMode(GL_MODELVIEW);  glPushMatrix();
 103         }
 104
 105         if (!(object->skip & GRITS_SKIP_CENTER))
 106                 grits_viewer_center_position(GRITS_VIEWER(opengl),
 107                                 object->center.lat,
 108                                 object->center.lon,
 109                                 object->center.elev);
 110
 111         if (pick && klass->pick)
 112                 klass->pick(object, opengl);
 113         else
 114                 klass->draw(object, opengl);
 115
 116         if (!(object->skip & GRITS_SKIP_STATE)) {
 117                 glPopAttrib();
 118                 glMatrixMode(GL_PROJECTION); glPopMatrix();
 119                 glMatrixMode(GL_MODELVIEW);  glPopMatrix();
 120         }
 121         g_mutex_unlock(opengl->sphere_lock);
 122 }
 123
 124 /**
 125  * grits_object_draw:
 126  * @object: the object
 127  * @opengl: the viewer the object is being displayed in
 128  *
 129  * Perform any OpenGL commands necessasairy to draw the object.
 130  *
 131  * The GL_PROJECTION and GL_MODELVIEW matricies and GL_ALL_ATTRIB_BITS will be
 132  * restored to the default state after the call to draw.
 133  */
 134 void grits_object_draw(GritsObject *object, GritsOpenGL *opengl)
 135 {
 136         grits_object_pickdraw(object, opengl, FALSE);
 137 }
 138
 139 void grits_object_hide(GritsObject *object, gboolean hidden)
 140 {
 141         GritsObjectClass *klass = GRITS_OBJECT_GET_CLASS(object);
 142         object->hidden = hidden;
 143         if (klass->hide)
 144                 klass->hide(object, hidden);
 145 }
 146
 147 void grits_object_queue_draw(GritsObject *object)
 148 {
 149         if (object->viewer)
 150                 gtk_widget_queue_draw(GTK_WIDGET(object->viewer));
 151 }
 152
 153 /* Event handling */
 154 void grits_object_pick_begin(GritsObject *object, GritsOpenGL *opengl)
 155 {
 156         object->state.picked = FALSE;
 157
 158         /* Check for connected signals */
 159         for (int i = 0; i < NUM_SIGNALS; i++) {
 160                 if (g_signal_has_handler_pending(object, signals[i], 0, FALSE)) {
 161                         /* Someone is watching, render the object _once_ */
 162                         glPushName((guint)object);
 163                         grits_object_pickdraw(object, opengl, TRUE);
 164                         glPopName();
 165                         return;
 166                 }
 167         }
 168 }
 169
 170 void grits_object_pick_pointer(GritsObject *object, double x, double y)
 171 {
 172         object->state.picked = TRUE;
 173 }
 174
 175 void grits_object_pick_end(GritsObject *object)
 176 {
 177         if (object->state.picked) {
 178                 if (!object->state.selected)
 179                         g_signal_emit(object, signals[SIG_ENTER], 0);
 180                 object->state.selected = TRUE;
 181         } else {
 182                 if (object->state.selected)
 183                         g_signal_emit(object, signals[SIG_LEAVE], 0);
 184                 object->state.selected = FALSE;
 185         }
 186 }
 187
 188 /* GObject stuff */
 189 G_DEFINE_ABSTRACT_TYPE(GritsObject, grits_object, G_TYPE_OBJECT);
 190 static void grits_object_init(GritsObject *object)
 191 {
 192         object->center.lat  =  0;
 193         object->center.lon  =  0;
 194         object->center.elev = -EARTH_R;
 195 }
 196
 197 static void grits_object_class_init(GritsObjectClass *klass)
 198 {
 199         GObjectClass *gobject_class = G_OBJECT_CLASS(klass);
 200
 201         /**
 202          * GritsObject::enter:
 203          * @object: the object.
 204          *
 205          * The ::enter signal is emitted when the pointer moves over the object
 206          */
 207         signals[SIG_ENTER] = g_signal_new(
 208                         "enter",
 209                         G_TYPE_FROM_CLASS(gobject_class),
 210                         G_SIGNAL_RUN_LAST,
 211                         0,
 212                         NULL,
 213                         NULL,
 214                         g_cclosure_marshal_VOID__VOID,
 215                         G_TYPE_NONE,
 216                         0);
 217
 218         /**
 219          * GritsViewer::leave:
 220          * @object: the object.
 221          *
 222          * The ::leave signal is emitted when the pointer moves away from the
 223          * object
 224          */
 225         signals[SIG_LEAVE] = g_signal_new(
 226                         "leave",
 227                         G_TYPE_FROM_CLASS(gobject_class),
 228                         G_SIGNAL_RUN_LAST,
 229                         0,
 230                         NULL,
 231                         NULL,
 232                         g_cclosure_marshal_VOID__VOID,
 233                         G_TYPE_NONE,
 234                         0);
 235 }