Add Blue Marble Next Gen plugin and tile rendering code

[grits] / src / gis-tile.c

diff --git a/src/gis-tile.c b/src/gis-tile.c
index ab45616a0e9b2d6d67b65d6b564908d2facb59b6..80772e67909d106786f6a6a79267f79d49c76884 100644 (file)
--- a/src/gis-tile.c
+++ b/src/gis-tile.c
@@ -35,6 +35,7 @@ GisTile *gis_tile_new(GisTile *parent,
        self->edge.s = s;
        self->edge.e = e;
        self->edge.w = w;
+       self->atime  = time(NULL);
        return self;
 }
 
@@ -54,6 +55,102 @@ gchar *gis_tile_get_path(GisTile *child)
        return g_string_free(path, FALSE);
 }
 
+gdouble _gis_tile_get_min_dist(GisTile *self,
+               gdouble lat, gdouble lon, gdouble elev)
+{
+       gdouble tlat  = lat > self->edge.n ? self->edge.n :
+                        lat < self->edge.s ? self->edge.s : lat;
+       gdouble tlon  = lon > self->edge.e ? self->edge.e :
+                       lon < self->edge.w ? self->edge.w : lon;
+       gdouble telev = 0; // TODO: elevation at rlat,rlon
+       //if (lat == tlat && lon == tlon)
+       //      return elev; /* Shortcut? */
+       gdouble a[3], b[3];
+       lle2xyz( lat,  lon,  elev, a+0, a+1, a+2);
+       lle2xyz(tlat, tlon, telev, b+0, b+1, b+2);
+       return distd(a, b);
+}
+
+gboolean _gis_tile_needs_split(GisTile *self,
+               gdouble max_res, gint width, gint height,
+               gdouble lat, gdouble lon, gdouble elev)
+{
+       gdouble lat_point = self->edge.n < 0 ? self->edge.n :
+                           self->edge.s > 0 ? self->edge.s : 0;
+       gdouble min_dist  = _gis_tile_get_min_dist(self, lat, lon, elev);
+       gdouble view_res  = MPPX(min_dist);
+       gdouble lon_dist  = self->edge.e - self->edge.w;
+       gdouble tile_res  = ll2m(lon_dist, lat_point)/width;
+
+       /* This isn't really right, but it helps with memory since we don't (yet?) test if the tile
+        * would be drawn */
+       gdouble scale = elev / min_dist;
+       view_res /= scale;
+       //g_message("tile=(%7.2f %7.2f %7.2f %7.2f) "
+       //          "eye=(%9.1f %9.1f %9.1f) "
+       //          "elev=%9.1f / dist=%9.1f = %f",
+       //              self->edge.n, self->edge.s, self->edge.e, self->edge.w,
+       //              lat, lon, elev,
+       //              elev, min_dist, scale);
+
+       if (tile_res < max_res)
+               return FALSE;
+       return view_res < tile_res;
+}
+
+void gis_tile_update(GisTile *self,
+               gdouble res, gint width, gint height,
+               gdouble lat, gdouble lon, gdouble elev,
+               GisTileLoadFunc load_func, gpointer user_data)
+{
+       self->atime = time(NULL);
+       //g_debug("GisTile: update - %p->atime = %u", self, (guint)self->atime);
+       gdouble lat_dist = self->edge.n - self->edge.s;
+       gdouble lon_dist = self->edge.e - self->edge.w;
+       if (_gis_tile_needs_split(self, res, width, height, lat, lon, elev)) {
+               gdouble lat_step = lat_dist / G_N_ELEMENTS(self->children);
+               gdouble lon_step = lon_dist / G_N_ELEMENTS(self->children[0]);
+               int x, y;
+               gis_tile_foreach_index(self, x, y) {
+                       if (!self->children[x][y]) {
+                               self->children[x][y] = gis_tile_new(self,
+                                               self->edge.n-(lat_step*(x+0)),
+                                               self->edge.n-(lat_step*(x+1)),
+                                               self->edge.w+(lon_step*(y+1)),
+                                               self->edge.w+(lon_step*(y+0)));
+                               load_func(self->children[x][y], user_data);
+                       }
+                       gis_tile_update(self->children[x][y],
+                                       res, width, height,
+                                       lat, lon, elev,
+                                       load_func, user_data);
+               }
+       }
+}
+
+GisTile *gis_tile_gc(GisTile *self, time_t atime,
+               GisTileFreeFunc free_func, gpointer user_data)
+{
+       if (!self)
+               return NULL;
+       gboolean has_children = FALSE;
+       int x, y;
+       gis_tile_foreach_index(self, x, y) {
+               self->children[x][y] = gis_tile_gc(
+                               self->children[x][y], atime,
+                               free_func, user_data);
+               if (self->children[x][y])
+                       has_children = TRUE;
+       }
+       //g_debug("GisTile: gc - %p->atime=%u < atime=%u",
+       //              self, (guint)self->atime, (guint)atime);
+       if (!has_children && self->atime < atime && self->data) {
+               free_func(self, user_data);
+               g_free(self);
+               return NULL;
+       }
+       return self;
+}
 
 void gis_tile_free(GisTile *self, GisTileFreeFunc free_func, gpointer user_data)
 {