From faea58469f1b01ec9d786491e2ca87405142862f Mon Sep 17 00:00:00 2001
From: Alexander Minges <alexander.minges@gmail.com>
Date: Fri, 1 May 2020 18:18:35 +0200
Subject: [PATCH] refactor code; adjust checks for dangerous blocks

---
 mods/ENTITIES/mcl_mobs/api.lua | 66 +++++++++++++++++++---------------
 1 file changed, 38 insertions(+), 28 deletions(-)

diff --git a/mods/ENTITIES/mcl_mobs/api.lua b/mods/ENTITIES/mcl_mobs/api.lua
index c027ce16..cb936510 100644
--- a/mods/ENTITIES/mcl_mobs/api.lua
+++ b/mods/ENTITIES/mcl_mobs/api.lua
@@ -300,6 +300,11 @@ end
 -- Returns true is node can deal damage to self
 local is_node_dangerous = function(self, nodename)
 	local nn = nodename
+	if self.fly then
+		if not minetest.get_item_group(nn, self.fly_in) then
+			return true
+		end
+	end
 	if self.water_damage > 0 then
 		if minetest.get_item_group(nn, "water") ~= 0 then
 			return true
@@ -317,7 +322,10 @@ local is_node_dangerous = function(self, nodename)
 	end
 	if minetest.registered_nodes[nn].drowning > 0 then
 		if self.breath_max ~= -1 then
-			return true
+			-- check if the mob is water-breathing _and_ the block is water; only return true if neither is the case
+			if not self.breathes_in_water and minetest.get_item_group(nn, "water") ~= 0 then
+				return true
+			end
 		end
 	end
 	if minetest.registered_nodes[nn].damage_per_second > 0 then
@@ -2013,8 +2021,12 @@ local do_states = function(self, dtime)
 		if (self.water_damage > 0
 		and self.lava_damage > 0)
 		or self.breath_max ~= -1 then
-
-			lp = minetest.find_node_near(s, 1, {"group:water", "group:lava"})
+			-- water-breathing mobs don't have to avoid water, but air
+			if self.breathes_in_water then
+				lp = minetest.find_node_near(s, 1, {"air", "group:lava"})
+			else 
+				lp = minetest.find_node_near(s, 1, {"group:water", "group:lava"})
+			end
 
 		elseif self.water_damage > 0 then
 
@@ -2032,44 +2044,42 @@ local do_states = function(self, dtime)
 
 		local is_in_danger = false
 		if lp then
-			-- if mob is flying, check if it is in its preferred medium
-			if self.fly then
-				if minetest.get_item_group(self.standing_in, self.fly_in) then
-					is_in_danger = false
-				elseif is_node_dangerous(self, self.standing_in) then
+			minetest.log(self.name .. ": " .. minetest.get_node(lp).name)
+			-- if mob is flying, only check the block it is inside
+			if self.fly then 
+				if is_node_dangerous(self, self.standing_in) then
 					is_in_danger = true
 				end
-			elseif (is_node_dangerous(self, self.standing_in) or
+			elseif not self.fly and (is_node_dangerous(self, self.standing_in) or
 				is_node_dangerous(self, self.standing_on)) then
 				is_in_danger = true
 			end
 			-- If mob in or on dangerous block, look for land
 			if is_in_danger then
-				minetest.log(self.name .. " is in/on dangerous node " .. self.standing_on .. " or " .. self.standing_in)
-				minetest.log(self.water_damage)
+				-- minetest.log(self.name .. " is in/on dangerous node " .. self.standing_on .. " or " .. self.standing_in)
 				lp = minetest.find_node_near(s, 5, {"group:solid"})
 
 				-- did we find land?
 				if lp then
 					local nn = minetest.get_node(lp).name
-					if is_node_dangerous(self, nn) then
-						-- is the chosen destination safe? Retry if not (max 10 iterations)
-						local i = 0
-						while i < 10 do
-							if lp then
-								nn = minetest.get_node(lp).name
-								minetest.log("Found solid block: " .. nn)
-								if not is_node_dangerous(self, nn) then break
-							end
-							-- look for solid node 5 blocks around the mob's position
-							elseif i < 5 then
-								lp = minetest.find_node_near(s, 5, {"group:solid"})
-							-- after 5 iterations double search radius
-							elseif i < 10 then
-								lp = minetest.find_node_near(s, 10, {"group:solid"})
-							end
-							i = i + 1
+					-- minetest.log(self.name .. " found land: " .. nn)
+
+					-- is the chosen destination safe and walkable? Retry if not (max 10 iterations)
+					local i = 0
+					while i < 10 do
+						if lp then
+							nn = minetest.get_node(lp).name
+							-- minetest.log("Found solid block: " .. nn)
+							if not is_node_dangerous(self, nn) and minetest.registered_nodes[nn].walkable then break
 						end
+						-- look for solid node 5 blocks around the mob's position
+						elseif i < 5 then
+							lp = minetest.find_node_near(s, 5, {"group:solid"})
+						-- after 5 iterations double search radius
+						elseif i < 10 then
+							lp = minetest.find_node_near(s, 10, {"group:solid"})
+						end
+						i = i + 1
 					end
 
 					local vec = {