improved vehicle destruction code

lib_planes/custom_physics.lua

@@ -7,6 +7,7 @@ function airutils.physics(self)
 	local surface = nil
 	local surfnodename = nil
 	local spos = airutils.get_stand_pos(self)
+    if not spos then return end
 	spos.y = spos.y+0.01
 	-- get surface height
 	local snodepos = airutils.get_node_pos(spos)

lib_planes/entities.lua

@@ -119,6 +119,10 @@ function airutils.on_step(self,dtime,colinfo)
 	    end
     end
     
+    if self.hp_max <= 0 then
+        airutils.destroy(self)
+    end
+
     self:physics()
 
     if self.logic then
@@ -214,6 +218,7 @@ function airutils.logic(self)
         end
     end
 
+    if not self.object:get_acceleration() then return end
     local accel_y = self.object:get_acceleration().y
     local rotation = self.object:get_rotation()
     local yaw = rotation.y

physics_lib.lua

@@ -42,9 +42,11 @@ function airutils.get_stand_pos(thing)	-- thing can be luaentity or objectref.
 	local colbox = {}
 	if type(thing) == 'table' then
 		pos = thing.object:get_pos()
+        if not thing.object:get_properties() then return false end
 		colbox = thing.object:get_properties().collisionbox
 	elseif type(thing) == 'userdata' then
 		pos = thing:get_pos()
+        if not thing:get_properties() then return false end
 		colbox = thing:get_properties().collisionbox
 	else 
 		return false