From b6c5893a300db8c4ff86fbb06e3ce02b53fe7ed4 Mon Sep 17 00:00:00 2001
From: teknomunk <teknomunk@protonmail.com>
Date: Sun, 7 Jul 2024 19:17:19 -0500
Subject: [PATCH] Move raycast_line_of_sight function to
 mcl_mobs/functions.lua, rework group spawn point selection code, add line of
 sight check to group origin

---
 mods/ENTITIES/mcl_mobs/functions.lua | 22 ++++++++++++++++
 mods/ENTITIES/mcl_mobs/init.lua      |  3 +++
 mods/ENTITIES/mcl_mobs/movement.lua  | 23 +----------------
 mods/ENTITIES/mcl_mobs/spawning.lua  | 38 ++++++++++++++++++----------
 4 files changed, 50 insertions(+), 36 deletions(-)
 create mode 100644 mods/ENTITIES/mcl_mobs/functions.lua

diff --git a/mods/ENTITIES/mcl_mobs/functions.lua b/mods/ENTITIES/mcl_mobs/functions.lua
new file mode 100644
index 000000000..ef47b299d
--- /dev/null
+++ b/mods/ENTITIES/mcl_mobs/functions.lua
@@ -0,0 +1,22 @@
+
+function mcl_mobs.check_line_of_sight(origin, target)
+	local raycast = minetest.raycast(origin, target, false, true)
+
+	local los_blocked = false
+	for hitpoint in raycast do
+		if hitpoint.type == "node" then
+			--TODO type object could block vision, for example chests
+			local node = minetest.get_node(minetest.get_pointed_thing_position(hitpoint))
+
+			if node.name ~= "air" then
+				local nodef = minetest.registered_nodes[node.name]
+				if nodef and nodef.walkable then
+					los_blocked = true
+					break
+				end
+			end
+		end
+	end
+	return not los_blocked
+end
+
diff --git a/mods/ENTITIES/mcl_mobs/init.lua b/mods/ENTITIES/mcl_mobs/init.lua
index 81b5fdfe7..99a94944c 100644
--- a/mods/ENTITIES/mcl_mobs/init.lua
+++ b/mods/ENTITIES/mcl_mobs/init.lua
@@ -6,6 +6,9 @@ local modname = minetest.get_current_modname()
 local path = minetest.get_modpath(modname)
 local S = minetest.get_translator(modname)
 mcl_mobs.fallback_node = minetest.registered_aliases["mapgen_dirt"] or "mcl_core:dirt"
+
+dofile(path .. "/functions.lua")
+
 --api and helpers
 -- effects: sounds and particles mostly
 dofile(path .. "/effects.lua")
diff --git a/mods/ENTITIES/mcl_mobs/movement.lua b/mods/ENTITIES/mcl_mobs/movement.lua
index ff9a38f56..5659c79ef 100644
--- a/mods/ENTITIES/mcl_mobs/movement.lua
+++ b/mods/ENTITIES/mcl_mobs/movement.lua
@@ -20,6 +20,7 @@ local function atan(x)
 		return atann(x)
 	end
 end
+local raycast_line_of_sight = mcl_mobs.check_line_of_sight
 
 local registered_fallback_node = minetest.registered_nodes[mcl_mobs.fallback_node]
 
@@ -77,28 +78,6 @@ function mob_class:is_node_waterhazard(nodename)
 end
 
 
-local function raycast_line_of_sight (origin, target)
-	local raycast = minetest.raycast(origin, target, false, true)
-
-	local los_blocked = false
-
-	for hitpoint in raycast do
-		if hitpoint.type == "node" then
-			--TODO type object could block vision, for example chests
-			local node = minetest.get_node(minetest.get_pointed_thing_position(hitpoint))
-
-			if node.name ~= "air" then
-				local nodef = minetest.registered_nodes[node.name]
-				if nodef and nodef.walkable then
-					los_blocked = true
-					break
-				end
-			end
-		end
-	end
-	return not los_blocked
-end
-
 function mob_class:target_visible(origin)
 	if not origin then return end
 
diff --git a/mods/ENTITIES/mcl_mobs/spawning.lua b/mods/ENTITIES/mcl_mobs/spawning.lua
index a455e7ae9..7e8e08626 100644
--- a/mods/ENTITIES/mcl_mobs/spawning.lua
+++ b/mods/ENTITIES/mcl_mobs/spawning.lua
@@ -33,6 +33,7 @@ local vector_floor    = vector.floor
 local table_copy     = table.copy
 local table_remove   = table.remove
 local pairs = pairs
+local check_line_of_sight = mcl_mobs.check_line_of_sight
 
 local LOGGING_ON = minetest.settings:get_bool("mcl_logging_mobs_spawning", false)
 local function mcl_log (message, property)
@@ -792,26 +793,35 @@ local function spawn_group(p, mob, spawn_on, amount_to_spawn, parent_state)
 	-- spawn in a given spot.
 	local o
 	while amount_to_spawn > 0 and #nn > 0 do
+		-- Find the next valid group spawn point
+		local sp
+		while #nn > 0 and not sp do
 		-- Select the next spawn position
-		local sp = vector.offset(nn[#nn],0,1,0)
-		nn[#nn] = nil
+			sp = vector.offset(nn[#nn],0,1,0)
+			nn[#nn] = nil
+
+			if spawn_protected and minetest.is_protected(sp, "") then
+				sp = nil
+			elseif not check_line_of_sight(p, sp) then
+				sp = nil
+			end
+		end
+		if not sp then return o end
 
 		-- Spawning prohibited in protected areas
-		if not (spawn_protected and minetest.is_protected(sp, "")) then
-			local state, node = build_state_for_position(sp, parent_state)
+		local state, node = build_state_for_position(sp, parent_state)
 
-			if spawn_check(sp, state, node, mob) then
-				if mob.type_of_spawning == "water" then
-					sp = get_water_spawn(sp)
-				end
+		if spawn_check(sp, state, node, mob) then
+			if mob.type_of_spawning == "water" then
+				sp = get_water_spawn(sp)
+			end
 
-				--minetest.log("Using spawn point "..vector.to_string(sp))
+			--minetest.log("Using spawn point "..vector.to_string(sp))
 
-				o = mcl_mobs.spawn(sp,mob.name)
-				if o then
-					amount_to_spawn = amount_to_spawn - 1
-					dbg_spawn_succ = dbg_spawn_succ + 1
-				end
+			o = mcl_mobs.spawn(sp,mob.name)
+			if o then
+				amount_to_spawn = amount_to_spawn - 1
+				dbg_spawn_succ = dbg_spawn_succ + 1
 			end
 		end
 	end