From f1141aed9fa52bf57e8867fdb3ffb520793dab07 Mon Sep 17 00:00:00 2001
From: jordan4ibanez <jordan4ibanez@users.noreply.github.com>
Date: Fri, 16 Apr 2021 21:08:54 -0400
Subject: [PATCH] Make mobs flop when outside of flying node

---
 .../mcl_mobs/api/mob_functions/ai.lua         | 37 ++++++++++++------
 .../mcl_mobs/api/mob_functions/movement.lua   | 39 ++++++++++++++++++-
 2 files changed, 62 insertions(+), 14 deletions(-)

diff --git a/mods/ENTITIES/mcl_mobs/api/mob_functions/ai.lua b/mods/ENTITIES/mcl_mobs/api/mob_functions/ai.lua
index 4313c29ce0..c77e0b1a59 100644
--- a/mods/ENTITIES/mcl_mobs/api/mob_functions/ai.lua
+++ b/mods/ENTITIES/mcl_mobs/api/mob_functions/ai.lua
@@ -193,41 +193,54 @@ 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)
+	
 
-	if self.state == "stand" then
+	--fly properly if inside fly node
+	if inside_fly_node then
+		if self.state == "stand" then
 
-		--do animation
-		--mobs.set_mob_animation(self, "stand")
+			--do animation
+			--mobs.set_mob_animation(self, "stand")
 
-		--set the velocity of the mob
-		--mobs.set_velocity(self,0)
+			--set the velocity of the mob
+			--mobs.set_velocity(self,0)
 
-		--print("standing")
+			--print("standing")
 
-	elseif self.state == "fly" then
+		elseif self.state == "fly" then
 
 
-		--print("flying")
+			--print("flying")
 
+		end
+	--flop around if not inside fly node
+	else
+		--print("flopping")
+		flop(self,dtime)
 	end
 
 end
diff --git a/mods/ENTITIES/mcl_mobs/api/mob_functions/movement.lua b/mods/ENTITIES/mcl_mobs/api/mob_functions/movement.lua
index 390a867789..09e21f4707 100644
--- a/mods/ENTITIES/mcl_mobs/api/mob_functions/movement.lua
+++ b/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_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
\ No newline at end of file