break recursive loops of Plugin::parameter_changed()->Plugin::ParameterChanged()->Plugin::parameter_changed() ...

git-svn-id: svn://localhost/ardour2/branches/3.0@13036 d708f5d6-7413-0410-9779-e7cbd77b26cf

libs/ardour/ladspa_plugin.cc

@@ -279,6 +279,11 @@ void
 LadspaPlugin::set_parameter (uint32_t which, float val)
 {
 	if (which < _descriptor->PortCount) {
+
+		if (get_parameter (which) == val) {
+			return;
+		}
+
 		_shadow_data[which] = (LADSPA_Data) val;
 
 #if 0

libs/ardour/lv2_plugin.cc

@@ -558,7 +558,14 @@ LV2Plugin::set_parameter(uint32_t which, float val)
 		            "%1 set parameter %2 to %3\n", name(), which, val));
 
 	if (which < lilv_plugin_get_num_ports(_impl->plugin)) {
+		
+		if (get_parameter (which) == val) {
+			return;
+		}
+		
 		_shadow_data[which] = val;
+		
+
 	} else {
 		warning << string_compose(
 		    _("Illegal parameter number used with plugin \"%1\". "

libs/ardour/vst_plugin.cc

@@ -101,6 +101,10 @@ VSTPlugin::get_parameter (uint32_t which) const
 void 
 VSTPlugin::set_parameter (uint32_t which, float val)
 {
+	if (get_parameter (which) == val) {
+		return;
+	}
+
 	_plugin->setParameter (_plugin, which, val);
 	Plugin::set_parameter (which, val);
 }