Make mobs flop when outside of flying node

mods/ENTITIES/mcl_mobs/api/mob_functions/ai.lua

@@ -193,26 +193,34 @@ local fly_state_switch = function(self, dtime)
 		self.state_timer = math.random(4,10) + math.random()
 		self.state = fly_state_list_wandering[math.random(1,#fly_state_list_wandering)]
 	end
-
 end
 
 
+--this is going to need some more logic gates because birds can flop around
+local flop = function(self,dtime)
+	mobs.flop(self)
+end
 
+
+-- states are executed here
 local fly_state_execution = function(self,dtime)
 
 	local pos = self.object:get_pos()
 	local current_node = minetest_get_node(pos).name
-	local inside_swim_node = false
+	local inside_fly_node = false
 
+	--quick scan everything to see if inside fly node
 	for _,id in pairs(self.fly_in) do
 		if id == current_node then
-			inside_swim_node = true
+			inside_fly_node = true
 			break
 		end
 	end
 
-	print(inside_swim_node)
 	
+
+	--fly properly if inside fly node
+	if inside_fly_node then
 		if self.state == "stand" then
 
 			--do animation
@@ -229,6 +237,11 @@ local fly_state_execution = function(self,dtime)
 			--print("flying")
 
 		end
+	--flop around if not inside fly node
+	else
+		--print("flopping")
+		flop(self,dtime)
+	end
 
 end
 

mods/ENTITIES/mcl_mobs/api/mob_functions/movement.lua

@@ -1,10 +1,15 @@
 local math_pi     = math.pi
 local math_sin    = math.sin
 local math_cos    = math.cos
+local math_random = math.random
+local DOUBLE_PI   = math_pi * 2
 
 -- localize vector functions
 local vector_new      = vector.new
 local vector_length   = vector.length
+local vector_multiply = vector.multiply
+
+local minetest_yaw_to_dir = minetest.yaw_to_dir
 
 -- move mob in facing direction
 --this has been modified to be internal
@@ -60,7 +65,37 @@ mobs.jump = function(self, velocity)
         return
     end
 
+	--fallback velocity to allow modularity
     velocity = velocity or 8
 
     self.object:add_velocity(vector_new(0,velocity,0))    
 end
+
+--make mobs flop
+mobs.flop = function(self, velocity)
+
+    if self.object:get_velocity().y ~= 0 or not self.old_velocity or (self.old_velocity and self.old_velocity.y > 0) then
+        return false
+    end
+
+	mobs.set_velocity(self, 0)
+
+	--fallback velocity to allow modularity
+    velocity = velocity or 8
+
+	--create a random direction (2d yaw)
+	local dir = DOUBLE_PI * math_random()
+
+	--create a random force value
+	local force = math_random(0,3) + math_random()
+
+	--convert the yaw to a direction vector then multiply it times the force
+	local final_additional_force = vector_multiply(minetest_yaw_to_dir(dir), force)
+
+	--place in the "flop" velocity to make the mob flop
+	final_additional_force.y = velocity	
+
+    self.object:add_velocity(final_additional_force)
+
+	return true
+end