mod-sneeker/entity.lua

local sounds_enabled = core.get_modpath("sounds") ~= nil
local hit_sound

if sounds_enabled then
	hit_sound = "sounds_entity_hit"
end


local function jump(self, pos, direction)
	local velocity = self.object:get_velocity()
	if core.registered_nodes[core.get_node(pos).name].climbable then
		self.object:set_velocity({x=velocity.x, y=4, z=velocity.z})
		return
	end

	local spos = {x=pos.x+direction.x, y=pos.y, z=pos.z+direction.z}
	local node = core.get_node_or_nil(spos)
	spos.y = spos.y+1
	local node2 = core.get_node_or_nil(spos)
	local def, def2 = {}
	if node and node.name then
		def = core.registered_items[node.name]
	end
	if node2 and node2.name then
		def2 = core.registered_items[node2.name]
	end
	if def and def.walkable
	and def2 and not def2.walkable
	and def.drawtype ~= "fencelike" then
		self.object:set_velocity({
			x = velocity.x*2.2,
			y = self.jump_height,
			z = velocity.z*2.2
		})
	end
end

local function random_turn(self)
	if self.turn_timer > math.random(2, 5) then
		local select_turn = math.random(1, 3)
		if select_turn == 1 then
			self.turn = "left"
		elseif select_turn == 2 then
			self.turn = "right"
		elseif select_turn == 3 then
			self.turn = "straight"
		end
		self.turn_timer = 0
		self.turn_speed = 0.05*math.random()
	end
end

local def = {
	hp_max = 20,
	physical = true,
	collisionbox = {-0.25, -0.7, -0.25, 0.25, 0.8, 0.25},
	visual = "mesh",
	mesh = "character.b3d",
	textures = {"sneeker.png"},
	makes_footstep_sound = false,

	-- Original
	animation = {
		stand_START = 0,
		stand_END = 79,
		walk_START = 168,
		walk_END = 187
	},
	walk_speed = 1.5,
	jump_height = 5,
	animation_speed = 30,
	knockback_level = 2
}

def.on_activate = function(self, staticdata)
	self.yaw = 0
	self.anim = 1
	self.timer = 0
	self.visualx = 1
	self.jump_timer = 0
	self.turn_timer = 0
	self.turn_speed = 0
	self.powered = false
	self.knockback = false
	self.state = math.random(1, 2)
	self.old_y = self.object:get_pos().y

	-- despawning
	self.lifetime = sneeker.lifetime
	self.lifetimer = 0
	self.check_despawn_player_distance = true

	local data = core.deserialize(staticdata)
	if data and type(data) == "table" then
		if data.powered == true then
			self.powered = true
			self.object:set_properties({textures = {"sneeker_powered.png"}})
		end
	else
		if math.random(0, 20) == 20 then
			self.powered = true
			self.object:set_properties({textures = {"sneeker_powered.png"}})
		end
	end
end


local function isnan(n)
	return tostring(n) == tostring((-1)^.5)
end

def.on_step = function(self, dtime)
	-- update lifetime timer
	-- FIXME: this is longer than realtime
	self.lifetimer = self.lifetimer + dtime
	if self.lifetimer >= self.lifetime then
		-- TODO: should have a death animation
		self.object:remove()
		return true
	end

	if self.knockback then
		return false
	end

	local ANIM_STAND = 1
	local ANIM_WALK  = 2

	local pos = self.object:get_pos()

	if sneeker.despawn_player_far then
		-- run check about once per 60 seconds
		local interval_reached = math.floor(self.lifetimer % 60) == 0
		if not interval_reached and not self.check_despawn_player_distance then
			self.check_despawn_player_distance = true
		end

		if interval_reached and self.check_despawn_player_distance then
			local player_nearby = false
			for _, entity in ipairs(core.get_objects_inside_radius(pos, sneeker.despawn_player_radius)) do
				if entity:is_player() then
					player_nearby = true
					break
				end
			end

			if not player_nearby then
				self.object:remove()
				return true
			end

			-- set flag to not check again until next interval
			self.check_despawn_player_distance = false
		end
	end

	local yaw = self.object:get_yaw()
	local inside = core.get_objects_inside_radius(pos, 10)
	local walk_speed = self.walk_speed
	local animation = self.animation
	local anim_speed = self.animation_speed
	local velocity = self.object:get_velocity()

	self.timer = self.timer+0.01
	self.turn_timer = self.turn_timer+0.01
	self.jump_timer = self.jump_timer+0.01

	if not self.chase
	and self.timer > math.random(2, 5) then
		if math.random() > 0.8 then
			self.state = "stand"
		else
			self.state = "walk"
		end
		self.timer = 0
	end

	if self.turn == "right" then
		self.yaw = self.yaw+self.turn_speed
		self.object:set_yaw(self.yaw)
	elseif self.turn == "left" then
		self.yaw = self.yaw-self.turn_speed
		self.object:set_yaw(self.yaw)
	end

	if self.chase and self.visualx < 2 then
		if self.hiss == false then
			core.sound_play("sneeker_hiss", {pos=pos, gain=1.5, max_hear_distance=2*64})
		end
		self.visualx = self.visualx+0.05
		self.object:set_properties({
			visual_size = {x=self.visualx, y=1}
		})
		self.hiss = true
	elseif self.visualx > 1 then
		self.visualx = self.visualx-0.05
		self.object:set_properties({
			visual_size = {x=self.visualx, y=1}
		})
		self.hiss = false
	end

	self.chase = false

	for  _, object in ipairs(inside) do
		if object:is_player() then
			self.state = "chase"
		end
	end

	if self.state == "stand" then
		if self.anim ~= ANIM_STAND then
			self.object:set_animation({x=animation.stand_START, y=animation.stand_END}, anim_speed, 0)
			self.anim = ANIM_STAND
		end

		random_turn(self)

		if velocity.x ~= 0
		or velocity.z ~= 0 then
			self.object:set_velocity({x=0, y=velocity.y, z=0})
		end
	end

	if self.state == "walk" then
		if self.anim ~= ANIM_WALK then
			self.object:set_animation({x=animation.walk_START, y=animation.walk_END}, anim_speed, 0)
			self.anim = ANIM_WALK
		end

		self.direction = {x=math.sin(yaw)*-1, y=-10, z=math.cos(yaw)}
		if self.direction then
			self.object:set_velocity({x=self.direction.x*walk_speed, y=velocity.y, z=self.direction.z*walk_speed})
		end

		random_turn(self)

		local velocity = self.object:get_velocity()

		if self.turn_timer > 1 then
			local direction = self.direction
			local npos = {x=pos.x+direction.x, y=pos.y+0.2, z=pos.z+direction.z}
			if velocity.x == 0 or velocity.z == 0
			or core.registered_nodes[core.get_node(npos).name].walkable then
				local select_turn = math.random(1, 2)
				if select_turn == 1 then
					self.turn = "left"
				elseif select_turn == 2 then
					self.turn = "right"
				end
				self.turn_timer = 0
				self.turn_speed = 0.05*math.random()
			end
		end

		-- Jump
		if self.jump_timer > 0.2 then
			jump(self, pos, self.direction)
		end
	end

	if self.state == "chase" then
		if self.anim ~= ANIM_WALK then
			self.object:set_animation({x=animation.walk_START, y=animation.walk_END}, anim_speed, 0)
			self.anim = ANIM_WALK
		end

		self.turn = "straight"

		local inside_2 = core.get_objects_inside_radius(pos, 2)

		-- Boom
		if #inside_2 ~= 0 then
			for  _, object in ipairs(inside_2) do
				if object:is_player() and object:get_hp() ~= 0 then
					self.chase = true
					if self.visualx >= 2 then
						self.object:remove()
						sneeker.boom(pos, self.powered)
						core.sound_play("sneeker_explode", {pos=pos, gain=sneeker.boom_gain, max_hear_distance=2*64})
						return true
					end
				end
			end
		end

		if #inside ~= 0 then
			for  _, object in ipairs(inside) do
				if object:is_player() and object:get_hp() ~= 0 then
					if #inside_2 ~= 0 then
						for _, object in ipairs(inside_2) do
							-- Stop move
							if object:is_player() then
								if self.anim ~= ANIM_STAND then
									self.object:set_animation({x=animation.stand_START, y=animation.stand_END}, anim_speed, 0)
									self.anim = ANIM_STAND
								end
								self.object:set_velocity({x=0, y=velocity.y, z=0})
								return
							end
						end
					end

					local ppos = object:get_pos()
					self.vec = {x=ppos.x-pos.x, y=ppos.y-pos.y, z=ppos.z-pos.z}
					self.yaw = math.atan(self.vec.z/self.vec.x)+math.pi^2
					if ppos.x > pos.x then
						self.yaw = self.yaw+math.pi
					end
					self.yaw = self.yaw-2
					self.object:set_yaw(self.yaw)
					self.direction = {x=math.sin(self.yaw)*-1, y=0, z=math.cos(self.yaw)}

					local direction = self.direction

					-- FIXME: hack
					local can_set = true
					for _, c in ipairs({direction.x*2.5, direction.z*2.5}) do
						if isnan(c) then
							can_set = false
							break
						end
					end

					if can_set then
						self.object:set_velocity({x=direction.x*2.5, y=velocity.y, z=direction.z*2.5})
					end

					-- Jump
					if self.jump_timer > 0.2 then
						jump(self, pos, direction)
					end
				end
			end
		else
			self.state = "stand"
		end
	end

	-- Swim
	local node = core.get_node(pos)
	if core.get_item_group(node.name, "water") ~= 0 then
		self.object:set_acceleration({x=0, y=1, z=0})
		local velocity = self.object:get_velocity()
		if self.object:get_velocity().y > 5 then
			self.object:set_velocity({x=0, y=velocity.y-velocity.y/2, z=0})
		else
			self.object:set_velocity({x=0, y=velocity.y+1, z=0})
		end
	else
		self.object:set_acceleration({x=0, y=-10, z=0})
	end

	return true
end

def.on_punch = function(self, puncher, time_from_last_punch, tool_capabilities, dir)
	if hit_sound then
		core.sound_play(hit_sound, {object=self.object}, parameters, true)
	end

	if self.knockback == false then
		local knockback_level = self.knockback_level
		self.object:set_velocity({x=dir.x*knockback_level, y=3, z=dir.z*knockback_level})
		self.knockback = true
		core.after(0.6, function()
			self.knockback = false
		end)
	end
	if self.object:get_hp() < 1 then
		local pos = self.object:get_pos()
		local x = 1/math.random(1, 5)*dir.x
		local z = 1/math.random(1, 5)*dir.z
		local p = {x=pos.x+x, y=pos.y, z=pos.z+z}
		local node = core.get_node_or_nil(p)
		if node == nil or not node.name or node.name ~= "air" then
			p = pos
		end
		local obj = core.add_item(p, {name="tnt:gunpowder", count=math.random(0, 2)})
	end
end

def.get_staticdata = function(self)
	return core.serialize({
		powered = self.powered
	})
end

core.register_entity("sneeker:sneeker", def)

core.register_craftitem("sneeker:spawnegg", {
	description = "Sneeker Spawn Egg",
	inventory_image = "sneeker_spawnegg.png",
	stack_max = 64,
	on_place = function(itemstack, placer, pointed_thing)
		if pointed_thing.type == "node" then
			local pos = pointed_thing.above
			pos.y = pos.y+1
			core.add_entity(pos, "sneeker:sneeker")
			if not core.settings:get_bool("creative_mode", false) then
				itemstack:take_item()
			end
			return itemstack
		end
	end
})