X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;ds=sidebyside;f=src%2Fgis-tile.c;h=7a0f0b832851c8e8d91535ad4844be651dfe4d6d;hb=82adb52036f7330bb6d47e354c24bcc13c34dd34;hp=ab45616a0e9b2d6d67b65d6b564908d2facb59b6;hpb=2e575e2c348f44d3c723ac344b7296492c76f77a;p=grits

diff --git a/src/gis-tile.c b/src/gis-tile.c
index ab45616..7a0f0b8 100644
--- 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 +55,124 @@ 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_find(GisTile *self, gdouble lat, gdouble lon)
+{
+	gint    rows = G_N_ELEMENTS(self->children);
+	gint    cols = G_N_ELEMENTS(self->children[0]);
+
+	gdouble lat_step = (self->edge.n - self->edge.s) / rows;
+	gdouble lon_step = (self->edge.e - self->edge.w) / cols;
+
+	gdouble lat_offset = self->edge.n - lat;;
+	gdouble lon_offset = lon - self->edge.w;
+
+	gint    row = lat_offset / lat_step;
+	gint    col = lon_offset / lon_step;
+
+	if (row < 0 || row >= rows || col < 0 || col >= cols)
+		return NULL;
+	else if (self->children[row][col] && self->children[row][col]->data)
+		return gis_tile_find(self->children[row][col], lat, lon);
+	else
+		return self;
+}
+
+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)
 {