musttest_game/mods/pm/entity.lua

-- Localize for performance.
local vector_distance = vector.distance
local vector_round = vector.round
local math_floor = math.floor
local math_max = math.max
local math_random = math.random

function pm.follower_on_activate(self, staticdata, dtime_s)
	if staticdata and staticdata ~= "" then
		local data = minetest.deserialize(staticdata)
		if type(data) == "table" then
			for k, v in pairs(data) do
				pm.debug_chat("on_activate(): self["..k.."]="..tostring(v))
				self[k] = v
			end
			return
		end
	end

	-- Otherwise, set up default data.
	self._timer = self._timer or 0
	self._lifetime = self._lifetime or 60*60*24
	self._sound_time = self._sound_time or 0
end

function pm.follower_get_staticdata(self)
	local data = {}
	for k, v in pairs(self) do
		local t = type(v)
		if t == "number" or t == "string" or t == "boolean" then
			if k:find("_") == 1 then
				pm.debug_chat("get_staticdata(): data["..k.."]="..tostring(v))
				data[k] = v
			end
		end
	end
	return minetest.serialize(data) or ""
end

function pm.get_wanted_velocity(self)
	if self and self._path then
		if #(self._path) > (pm.sight_range * 0.75) then
			return pm.run_velocity
		elseif #(self._path) < 5 then
			return pm.walk_velocity
		else
			return pm.velocity
		end
	end
	return pm.velocity
end

function pm.follower_on_step(self, dtime, moveresult)
	-- Remove object once we're old enough.
	if not self._lifetime then
		self.object:remove()
		return
	end
	if not self._no_lifespan_limit then
		self._lifetime = self._lifetime - dtime
		if self._lifetime < 0 then
			self.object:remove()
			return
		end
	end

	-- Cooldown timer for the pathfinder, since using it is intensive.
	if self._failed_pathfind_cooldown then
		self._failed_pathfind_cooldown = self._failed_pathfind_cooldown - dtime
		if self._failed_pathfind_cooldown < 0 then
			self._failed_pathfind_cooldown = nil

			-- Also reset path/target info so we have a chance to acquire fresh data.
			self._goto = nil
			self._path = nil
		end
	end

	if self._acquire_target_cooldown then
		self._acquire_target_cooldown = self._acquire_target_cooldown - dtime
		if self._acquire_target_cooldown < 0 then
			self._acquire_target_cooldown = nil
		end
	end

	if self._wander_cooldown then
		self._wander_cooldown = self._wander_cooldown - dtime
		if self._wander_cooldown < 0 then
			self._wander_cooldown = nil
		end
	end

	-- Entity changes its behavior every so often.
	if not self._no_autochose_behavior then
		if not self._behavior_timer or self._behavior_timer < 0 then
			self._behavior_timer = math_random(1, 20)*60
			pm.choose_random_behavior(self)
		end
		self._behavior_timer = self._behavior_timer - dtime
	end

	-- Entities sometimes get stuck against objects.
	-- Unstick them by rounding their positions to the nearest air node.
	if not self._unstick_timer or self._unstick_timer < 0 then
		self._unstick_timer = math_random(1, 30)
		local air = minetest.find_node_near(self.object:get_pos(), 1, "air", true)
		if air then
			self.object:set_pos(air)
		end
	end
	self._unstick_timer = self._unstick_timer - dtime

	-- Sound timer.
	if not self._sound_time then self._sound_time = 0 end
	self._sound_time = self._sound_time - dtime
	if self._sound_time < 0 then
		self._sound_time = math_random(100, 300)/100
		if not self._no_sound then
			ambiance.sound_play("wisp", self.object:get_pos(), 0.2, 32)
		end
	end

	-- If currently following a path, remove waypoints as we reach them.
	if self._path and #(self._path) > 0 then
		local p = self._path[1]
		-- Remove waypoint from path if we've reached it.
		if vector_distance(p, self.object:get_pos()) < 0.75 then
			pm.debug_chat('hit waypoint')
			self._stuck_timer = 2
			table.remove(self._path, 1)
		end

		-- Remove path when all waypoints exhausted.
		if #(self._path) < 1 then
			pm.debug_chat('finished following path: ' .. minetest.pos_to_string(self._goto))
			pm.debug_chat('node at terminus: ' .. minetest.get_node(self._goto).name)
			self._path = nil
			self._path_is_los = nil
			self._stuck_timer = nil
			self._failed_pathfind_cooldown = nil
			self.object:set_velocity({x=0, y=0, z=0})
		end

		if self._stuck_timer then
			self._stuck_timer = self._stuck_timer - dtime
			if self._stuck_timer < 0 then
				pm.debug_chat('got stuck following path')
				-- Got stuck trying to follow path.
				-- This is caused because the entity is physical and may collide with
				-- the environment. Blocks may have been added in the entity's path, or
				-- (more usually) the entity did not properly navigate a corner.
				-- We should seek a new target.
				self._goto = nil
				self._path = nil
				self._target = nil
				self._failed_pathfind_cooldown = math_random(pm.pf_cooldown_min, pm.pf_cooldown_max)
				self._stuck_timer = nil
				self._wander_cooldown = nil
				self.object:set_velocity({x=0, y=0, z=0})
			end
		end
	end

	-- Main logic timer.
	-- This controls how often the main "AI" logic runs.
	self._timer = self._timer + dtime
	if self._timer < 0.3 then return end
	self._timer = 0

	-- Spawn particles to indicate our location.
	local pos = self.object:get_pos()
	pm.follower_spawn_particles(pos, self.object)

	-- Find new target/goal-waypoint if we don't have one.
	if not self._acquire_target_cooldown and not self._failed_pathfind_cooldown then
		if not self._goto and not self._path then
			local tp, target = self._interest_point(self, pos)
			if target then
				-- Target is another entity.
				pm.debug_chat('acquired moving target')
				--if target:is_player() then pm.debug_chat('targeting player') end
				local s = tp
				if not s then s = target:get_pos() end
				if s then
					s = vector_round(s)
					if pm.target_is_player_or_mob(target) then
						s.y = s.y + 1 -- For players or mobs, seek above them, not at their feet.
					end
					s = minetest.find_node_near(s, 1, "air", true)
					-- Target must be standing in air.
					-- Otherwise it would never be reachable.
					if s then
						-- Don't reacquire target if we're already sitting on it.
						if vector_distance(pos, s) > pm.range then
							pm.debug_chat('set moving target goal')
							self._goto = vector_round(s)
							self._target = target -- Userdata object.
						end
					end
				end
				self._acquire_target_cooldown = math_random(pm.aq_cooldown_min, pm.aq_cooldown_max)
			elseif tp then
				-- Target is a static location.
				pm.debug_chat('acquired static target')
				-- Don't reacquire target if we're already sitting on it.
				if vector_distance(pos, tp) > pm.range then
					pm.debug_chat('set static target goal')
					self._goto = vector_round(tp)
					self._target = nil
				end
				self._acquire_target_cooldown = math_random(pm.aq_cooldown_min, pm.aq_cooldown_max)
			else
				-- No target acquired. Wait awhile before calling function again.
				pm.debug_chat('no target acquired')
				self._acquire_target_cooldown = math_random(pm.aq_cooldown_min, pm.aq_cooldown_max)
			end
		end
	end

	-- Get a path to our target if we don't have a path yet, and target is not nearby.
	if not self._failed_pathfind_cooldown then
		if self._goto and not self._path and vector_distance(self._goto, pos) > pm.range then
			pm.debug_chat('want path to target')
			local los, obstruction = minetest.line_of_sight(vector_round(pos), vector_round(self._goto))
			if los then
				-- We have LOS (line of sight) direct to target.
				pm.debug_chat('LOS confirmed')
				local dir = vector.subtract(vector_round(self._goto), vector_round(pos))
				local dst = vector.length(dir)
				dir = vector.normalize(dir) -- Returns 0,0,0 for zero-length vector.

				-- Assemble a straight-line path.
				local path = {}
				for i=1, dst, 1 do
					path[#path+1] = vector.add(pos, vector.multiply(dir, i))
				end
				if #path > 0 then
					self._path = path
					self._path_is_los = true
					self._stuck_timer = nil
				end
			else
				-- No line of sight to target. Use pathfinder!
				pm.debug_chat('will try pathfinder')
				local rp1 = vector_round(pos)
				local rp2 = vector_round(self._goto)

				local a1 = rp1
				local a2 = rp2

				local d1 = minetest.registered_nodes[minetest.get_node(rp1).name]
				local d2 = minetest.registered_nodes[minetest.get_node(rp2).name]

				-- If either start or end are non-walkable, we don't need to look for air.
				if d1.walkable then
					a1 = minetest.find_node_near(rp1, 2, "air", true)
				end
				if d2.walkable then
					a2 = minetest.find_node_near(rp2, 2, "air", true)
				end

				if a1 and a2 then
					pm.debug_chat('start and end position are both in air')
					local prepath = {table.copy(a1)}
					local postpath = {table.copy(a2)}

					-- Find air directly above ground for the wisp's start position.
					-- This is necessary because the wisp usually flies a little bit above
					-- the ground. Pathfinding will fail if we don't start at ground level.
					while minetest.get_node(vector.add(a1, {x=0, y=-1, z=0})).name == "air" do
						a1.y = a1.y - 1
						table.insert(prepath, table.copy(a1))
					end
					-- Find air directly above ground for the target position.
					local target_y = a2.y
					while minetest.get_node(vector.add(a2, {x=0, y=-1, z=0})).name == "air" do
						a2.y = a2.y - 1
						table.insert(postpath, 1, table.copy(a2))
					end

					-- If this triggers then the target is flying, or hanging over a high ledge.
					if (target_y - a2.y) > 2 then
					end

					-- The shorter the apparent distance between these 2 points, the farther
					-- we can afford to look around.
					local d = vector_distance(a1, a2)
					local r = math_max(10, math_floor(pm.sight_range - d))

					pm.debug_chat("trying to find path")
					self._path = minetest.find_path(a1, a2, r, 1, 1, "A*_noprefetch")

					if not self._path then
						pm.debug_chat('no path found')
						-- If we couldn't find a path to this location, we should remove this
						-- goal. Also set the pathfinder cooldown timer.
						self._goto = nil
						self._failed_pathfind_cooldown = math_random(pm.pf_cooldown_min, pm.pf_cooldown_max)
					else
						if #(self._path) >= 1 then
							pm.debug_chat("got path")
							self._stuck_timer = nil

							pm.debug_chat('welding pre and post paths')
							local path = {}
							for i=1, #prepath, 1 do
								path[#path+1] = prepath[i]
							end
							for i=1, #(self._path), 1 do
								path[#path+1] = self._path[i]
							end
							for i=1, #postpath, 1 do
								path[#path+1] = postpath[i]
							end
							self._path = path
							self._stuck_timer = nil

							-- Debug render path.
							pm.debug_path(self._path)

							-- If start and end points are equal, toss this path out.
							-- Also set the pathfinder cooldown timer.
							if vector.equals(self._path[1], self._path[#(self._path)]) then
								pm.debug_chat('tossing path because start and end are equal')
								self._path = nil
								self._goto = nil
								self._failed_pathfind_cooldown = math_random(pm.pf_cooldown_min, pm.pf_cooldown_max)
							end

							-- If path's start position is too far away, we can't use the path.
							if self._path then
								if vector_distance(self._path[1], pos) > pm.range then
									pm.debug_chat('tossing path because start is too far away')
									self._path = nil
									self._goto = nil
									self._failed_pathfind_cooldown = math_random(pm.pf_cooldown_min, pm.pf_cooldown_max)
								end
							end
						else
							-- Not a real path!
							-- Must have at least one position.
							pm.debug_chat('tossing path because it is bogus')
							self._goto = nil
							self._path = nil
							self._failed_pathfind_cooldown = math_random(pm.pf_cooldown_min, pm.pf_cooldown_max)
						end
					end
				else
					-- One or both positions not accessible (no nearby air).
					-- Thus we must give up this target.
					self._goto = nil
					self._path = nil
					self._failed_pathfind_cooldown = math_random(pm.pf_cooldown_min, pm.pf_cooldown_max)
				end
			end
		end
	end

	-- Follow current path.
	if self._path and #(self._path) > 0 then
		-- For paths of longer than trivial length, try to optimize with LOS.
		-- We can do this because this mob can fly over gaps and such. This also
		-- makes the movement look better.
		if #(self._path) > 5 then
			-- Don't do LOS optimization if the current waypoint is already so marked.
			local p = self._path[2]
			if not p.los then
				while #(self._path) > 1 and minetest.line_of_sight(pos, p) do
					table.remove(self._path, 1)
					p = self._path[2]
				end

				local dir = vector.subtract(self._path[1], pos)
				local dst = vector.length(dir)
				dir = vector.normalize(dir) -- Returns 0,0,0 for zero-length vector.

				-- Assemble a straight-line path.
				local path = {}
				for i=1, dst, 1 do
					path[#path+1] = vector.add(pos, vector.multiply(dir, i))
					path[#path].los = true -- Mark waypoint as a LOS point.
				end

				-- Append the remainder of the real path.
				for i=1, #(self._path), 1 do
					path[#path+1] = self._path[i]
				end

				-- Set new path.
				self._path = path
				self._stuck_timer = nil

				-- Debug render path.
				pm.debug_path(self._path)
			end
		end

		pm.debug_chat('following path')
		local waypoint = self._path[1]
		local waynode = minetest.get_node(waypoint)

		-- Check if path runs through an obstruction.
		-- Nodes must be 'air' or non-walkable (like plants).
		local obstructed = false
		if waynode.name ~= "air" then
			local ndef = minetest.registered_nodes[waynode.name]
			if not ndef or ndef.walkable then
				obstructed = true
			end
		end

		if not obstructed then
			if self._path_is_los or waypoint.los then
				-- Follow line-of-sight paths directly.
				--self.object:move_to(waypoint, true)
				--table.remove(self._path, 1)

				-- Smooth movement.
				local dir = vector.subtract(waypoint, pos)
				if vector.length(dir) > 0.4 then
					dir = vector.normalize(dir)
					dir = vector.multiply(dir, pm.get_wanted_velocity(self))
					self.object:set_velocity(dir)
				end
			else
				-- Cause entity to float 1.5 meters above ground when following path,
				-- if there's enough head room. But not for the last waypoint in the path.
				waypoint.y = waypoint.y + 1
				local n = minetest.get_node(waypoint)

				if n.name == "air" and #(self._path) > 1 then
					waypoint.y = waypoint.y - 0.5
					--self.object:move_to(waypoint, true)
					--table.remove(self._path, 1)

					-- Smooth movement.
					local dir = vector.subtract(waypoint, pos)
					if vector.length(dir) > 0.4 then
						dir = vector.normalize(dir)
						dir = vector.multiply(dir, pm.get_wanted_velocity(self))
						self.object:set_velocity(dir)
					end
				else
					waypoint.y = waypoint.y - 1
					--self.object:move_to(waypoint, true)
					--table.remove(self._path, 1)

					-- Smooth movement.
					local dir = vector.subtract(waypoint, pos)
					if vector.length(dir) > 0.4 then
						dir = vector.normalize(dir)
						dir = vector.multiply(dir, pm.get_wanted_velocity(self))
						self.object:set_velocity(dir)
					end
				end
			end
		else
			-- Path obstructed. Need new path, this one is bad.
			pm.debug_chat('path obstructed: ' .. waynode.name)
			self._path = nil
			self._path_is_los = nil
			self._goto = nil
			self.object:set_velocity({x=0, y=0, z=0})
		end
	end

	-- Dynamic targets can move while we're trying to path to them.
	-- Update path as long as we have LOS to the target.
	if self._target and self._path and self._goto then
		local target_pos = self._target:get_pos()
		if target_pos then
			if #(self._path) > 0 then
				local end_path = self._path[#(self._path)]
				if vector_distance(target_pos, end_path) > 3 then
					local los, obstruction = minetest.line_of_sight(vector_round(pos), vector_round(target_pos))
					if los then
						pm.debug_chat('target moved, repathing via LOS')
						self._goto = vector_round(target_pos)

						local dir = vector.subtract(self._goto, vector_round(pos))
						local dst = vector.length(dir)
						dir = vector.normalize(dir) -- Returns 0,0,0 for zero-length vector.

						-- Assemble a straight-line path.
						local path = {}
						for i=1, dst, 1 do
							path[#path+1] = vector.add(pos, vector.multiply(dir, i))
						end
						if #path > 0 then
							self._path = path
							self._path_is_los = true
							self._stuck_timer = nil
						end
					end
				end
			end
		end
	end

	-- Remove target waypoint once we're close enough to it.
	-- Only if done following path.
	if self._goto and not self._path then
		pm.debug_chat('distance to goal: ' .. vector_distance(self._goto, pos))
		pm.debug_goal(self._goto)
		if vector_distance(self._goto, pos) < pm.range then
			pm.debug_chat('reached goal')
			--self.object:move_to(self._goto, true)

			-- Have we arrived at the target (if we did indeed have a target)?
			if self._target then
				local s = self._target:get_pos()
				if s then
					s = vector_round(s)
					s.y = s.y + 1 -- For entities, we seek above them, not at their feet.
					if vector_distance(pos, s) < pm.range then
						pm.debug_chat('reached dynamic target')
						-- We have reached our moveable target.
						-- We can clear this and set a timer to delay acquiring the next target.
						self._on_arrival(self, self._goto, self._target)
						self._goto = nil
						self._target = nil
						self._acquire_target_cooldown = math_random(pm.aq_cooldown_min, pm.aq_cooldown_max)
					else
						-- Our moveable target has moved. We must move toward it again.
						-- Do so right away, without delay.
						pm.debug_chat('target has moved, reacquiring')
						self._goto = s
						self._acquire_target_cooldown = nil
						self._failed_pathfind_cooldown = nil
					end
				else
					-- Moving target no longer available. We must clear this.
					self._target = nil
					self._goto = nil
				end
			else
				pm.debug_chat('reached static target')
				self._on_arrival(self, self._goto, nil)
				-- No moving target, so we can clear this.
				self._goto = nil
				self._acquire_target_cooldown = math_random(pm.aq_cooldown_min, pm.aq_cooldown_max)
			end
		end
	end

	-- Drift behavior, as long as we don't have a target to go to.
	if not self._wander_cooldown then
		if not self._goto then
			local dir = {
				x = math_random(-1, 1)/10,
				y = math_random(-1, 1)/10,
				z = math_random(-1, 1)/10
			}
			self.object:set_velocity(dir)
			self._wander_cooldown = math_random(1, 5)
		end
	end
end

function pm.follower_on_punch(self, puncher, time_from_last_punch, tool_capabilities, dir)
	local pos = self.object:get_pos()
	pm.death_particle_effect(pos)
	minetest.add_item(pos, "glowstone:glowing_dust " .. math_random(1, 3))
	self.object:remove()
end