Avoid excess threads with g_mutex_trylock

[grits] / src / plugins / elev.c

diff --git a/src/plugins/elev.c b/src/plugins/elev.c
index 83b2e7bbfe74517fa4fc8e084916fe09f18ee495..9279b08190ca9c6e1ec314077b2e4cc52d26da73 100644 (file)
--- a/src/plugins/elev.c
+++ b/src/plugins/elev.c
@@ -15,6 +15,16 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+/**
+ * SECTION:elev
+ * @short_description: Elevation plugin
+ *
+ * #GisPluginElev provides access to ground elevation. It does this in two ways:
+ * First, it provides a height function used by the viewer when drawing the
+ * world. Second, it can load the elevation data into an image and draw a
+ * greyscale elevation overlay on the planets surface.
+ */
+
 #include <gtk/gtkgl.h>
 #include <glib/gstdio.h>
 #include <GL/gl.h>
@@ -153,8 +163,8 @@ static guint _load_opengl(GdkPixbuf *pixbuf)
                        (alpha ? GL_RGBA : GL_RGB), GL_UNSIGNED_BYTE, pixels);
        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
-       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER);
-       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);
+       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
+       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
 
        g_debug("GisPluginElev: load_opengl %d", opengl);
        return opengl;
@@ -236,7 +246,8 @@ static void _free_tile(GisTile *tile, gpointer _elev)
 static gpointer _update_tiles(gpointer _elev)
 {
        GisPluginElev *elev = _elev;
-       g_mutex_lock(elev->mutex);
+       if (!g_mutex_trylock(elev->mutex))
+               return NULL;
        gdouble lat, lon, elevation;
        gis_viewer_get_location(elev->viewer, &lat, &lon, &elevation);
        gis_tile_update(elev->tiles,
@@ -258,9 +269,24 @@ static void _on_location_changed(GisViewer *viewer,
        g_thread_create(_update_tiles, elev, FALSE, NULL);
 }
 
+static gpointer _threaded_init(GisPluginElev *elev)
+{
+       _load_tile(elev->tiles, elev);
+       _update_tiles(elev);
+       return NULL;
+}
+
 /***********
  * Methods *
  ***********/
+/**
+ * gis_plugin_elev_new:
+ * @viewer: the #GisViewer to use for drawing
+ *
+ * Create a new instance of the elevation plugin.
+ *
+ * Returns: the new #GisPluginElev
+ */
 GisPluginElev *gis_plugin_elev_new(GisViewer *viewer)
 {
        g_debug("GisPluginElev: new");
@@ -268,8 +294,7 @@ GisPluginElev *gis_plugin_elev_new(GisViewer *viewer)
        elev->viewer = g_object_ref(viewer);
 
        /* Load initial tiles */
-       _load_tile(elev->tiles, elev);
-       g_thread_create(_update_tiles, elev, FALSE, NULL);
+       g_thread_create((GThreadFunc)_threaded_init, elev, FALSE, NULL);
 
        /* Connect signals */
        elev->sigid = g_signal_connect(elev->viewer, "location-changed",