Make spiders climb up walls, fix problems with mob following freaking out when under, fix spider collisionbox

mods/ENTITIES/mcl_mobs/api/api.lua

@@ -325,6 +325,13 @@ function mobs:register_mob(name, def)
 		projectile_cooldown_min = def.projectile_cooldown_min or 2,
 		projectile_cooldown_max = def.projectile_cooldown_max or 6,
 		skittish = def.skittish,
+
+		minimum_follow_distance = def.minimum_follow_distance or 0.5, --make mobs not freak out when underneath
+
+		--for spiders
+		always_climb = def.always_climb,
+
+		--despawn mechanic variables
 		lifetimer_reset = 30, --30 seconds
 		lifetimer = 30, --30 seconds
 

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

@@ -204,9 +204,11 @@ local land_state_execution = function(self,dtime)
 
 		--check distance
 		local distance_from_follow_person = vector_distance(self.object:get_pos(), self.following_person:get_pos())
+		local distance_2d = mobs.get_2d_distance(self.object:get_pos(), self.following_person:get_pos())
 				
 		--don't push the player if too close
-		if self.follow_distance < distance_from_follow_person then
+		--don't spin around randomly
+		if self.follow_distance < distance_from_follow_person and self.minimum_follow_distance < distance_2d then
 			mobs.set_mob_animation(self, "run")
 			mobs.set_velocity(self,self.run_velocity)
 

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

@@ -120,9 +120,15 @@ mobs.punch_attack_walk = function(self,dtime)
         return
     end
 
-    mobs.set_yaw_while_attacking(self)
+    local distance_from_attacking = mobs.get_2d_distance(self.object:get_pos(), self.attacking:get_pos())
 
-    mobs.set_velocity(self, self.run_velocity)
+    if distance_from_attacking >= self.minimum_follow_distance then
+        mobs.set_velocity(self, self.run_velocity)
+    else
+        mobs.set_velocity(self, 0)
+    end
+
+    mobs.set_yaw_while_attacking(self)
 
     mobs.set_mob_animation(self, "run")
 
@@ -130,10 +136,16 @@ mobs.punch_attack_walk = function(self,dtime)
     --check for nodes to jump over
     --explosive mobs will just ride against walls for now
 	local node_in_front_of = mobs.jump_check(self)
+
 	if node_in_front_of == 1 then
 		mobs.jump(self)
     end
 
+    --mobs that can climb over stuff
+    if self.always_climb and node_in_front_of > 0 then
+        mobs.climb(self)
+    end
+
 
     --auto reset punch_timer
     if not self.punch_timer then

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

@@ -235,4 +235,12 @@ mobs.check_for_player_within_area = function(self, radius)
 	end
 	--did not find a player
 	return(false)
+end
+
+
+--a simple helper function for mobs following
+mobs.get_2d_distance = function(pos1,pos2)
+	pos1.y = 0
+	pos2.y = 0
+	return(vector_distance(pos1, pos2))
 end

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

@@ -16,6 +16,7 @@ local minetest_dir_to_yaw = minetest.dir_to_yaw
 
 local DEFAULT_JUMP_HEIGHT = 5
 local DEFAULT_FLOAT_SPEED = 4
+local DEFAULT_CLIMB_SPEED = 3
 
 
 
@@ -41,6 +42,28 @@ mobs.float = function(self)
 	end
 end
 
+--this is a generic climb function
+mobs.climb = function(self)
+
+	local current_velocity = self.object:get_velocity()
+
+	local goal_velocity = {
+		x = 0,
+		y = DEFAULT_CLIMB_SPEED,
+		z = 0,
+	}
+
+	local new_velocity_addition = vector.subtract(goal_velocity,current_velocity)
+
+	new_velocity_addition.x = 0
+	new_velocity_addition.z = 0
+
+	--smooths out mobs a bit
+	if vector_length(new_velocity_addition) >= 0.0001 then
+		self.object:add_velocity(new_velocity_addition)
+	end
+end
+
 
 
 --[[

mods/ENTITIES/mobs_mc/spider.lua

@@ -16,17 +16,21 @@ local spider = {
 	type = "monster",
 	spawn_class = "hostile",
 	passive = false,
+	hostile = true,
+	always_climb = true,
 	docile_by_day = true,
 	attack_type = "punch",
-	pathfinding = 1,
+	punch_timer_cooloff = 0.5,
+	rotate = 270,
 	damage = 2,
 	reach = 2,
 	hp_min = 16,
 	hp_max = 16,
 	xp_min = 5,
 	xp_max = 5,
+	eye_height = 0.475,
 	armor = {fleshy = 100, arthropod = 100},
-	collisionbox = {-0.7, -0.01, -0.7, 0.7, 0.89, 0.7},
+	collisionbox = {-0.45, 0, -0.45, 0.45, 0.9, 0.45},
 	visual = "mesh",
 	mesh = "mobs_mc_spider.b3d",
 	textures = {
@@ -43,7 +47,7 @@ local spider = {
 		distance = 16,
 	},
 	walk_velocity = 1.3,
-	run_velocity = 2.8,
+	run_velocity = 2.75, --spider can become extremely difficult if any higher
 	jump = true,
 	jump_height = 4,
 	view_range = 16,