Improved Boids and Context Steering

boids.lua

@@ -3,7 +3,18 @@
 -----------
 
 local abs = math.abs
-local random = math.random
+local atan2 = math.atan2
+local sin = math.sin
+local cos = math.cos
+
+local function average_angle(tbl)
+	local sum_sin, sum_cos = 0, 0
+	for _, v in pairs(tbl) do
+		sum_sin = sum_sin + sin(v)
+		sum_cos = sum_cos + cos(v)
+	end
+	return atan2(sum_sin, sum_cos)
+end
 
 local function average(tbl)
 	local sum = 0
@@ -13,20 +24,17 @@ local function average(tbl)
 	return sum / #tbl
 end
 
-local function average_angle(tbl)
-	local sum_sin, sum_cos = 0, 0
-	for _, v in pairs(tbl) do
-		sum_sin = sum_sin + math.sin(v)
-		sum_cos = sum_cos + math.cos(v)
-	end
-	return math.atan2(sum_sin, sum_cos)
+local function interp_rad(a, b, w)
+	local cs = (1 - w) * cos(a) + w * cos(b)
+	local sn = (1 - w) * sin(a) + w * sin(b)
+	return atan2(sn, cs)
 end
 
-local vec_dist = vector.distance
-local vec_dir = vector.direction
 local vec_add = vector.add
-local vec_normal = vector.normalize
+local vec_dir = vector.direction
+local vec_dist = vector.distance
 local vec_divide = vector.divide
+local vec_normal = vector.normalize
 
 local function get_average_pos(vectors)
 	local sum = {x = 0, y = 0, z = 0}
@@ -53,13 +61,91 @@ local dir2yaw = minetest.dir_to_yaw
 
 -- Get Boid Members --
 
--- This function scans within
--- a set radius for potential
--- boid members, and assigns
--- a leader. A new leader
--- is only assigned every 12
--- seconds or if a new mob
--- is in the boid.
+function creatura.get_boid_cached(self)
+	local pos = self.object:get_pos()
+	if not pos then return end
+	local radius = self.tracking_range * 0.5 or 4
+	local members = self._movement_data.boids or {}
+	local max_boids = self.max_boids or 7
+	if #members > 0 then
+		for i = #members, 1, -1 do
+			local object = members[i]
+			if not object or not object:get_yaw() then members[i] = nil end
+		end
+		if #members >= max_boids then return members end
+	end
+	local objects = minetest.get_objects_inside_radius(pos, radius)
+	if #objects < 2 then return {} end
+	for _, object in ipairs(objects) do
+		local ent = object and object ~= self.object and object:get_luaentity()
+		if ent
+		and ent.name == self.name then
+			local move_data = ent._movement_data
+			if move_data
+			and (not move_data.boids
+			or #move_data.boids < max_boids) then
+				table.insert(members, object)
+			end
+		end
+		if #members >= max_boids then break end
+	end
+	self._movement_data.boids = members
+
+	return members
+end
+
+-- Calculate Boid Movement Direction
+
+function creatura.get_boid_dir(self)
+	local pos = self.object:get_pos()
+	if not pos then return end
+	local boids = creatura.get_boid_cached(self)
+	if #boids < 2 then return end
+	local pos_no, pos_sum = 0, {x = 0, y = 0, z = 0}
+	local sum_sin, sum_cos = 0, 0
+	local lift_no, lift_sum = 0, 0
+
+	local vel
+	local boid_pos
+	local closest_pos
+	for _, object in ipairs(boids) do
+		if object then
+			boid_pos, vel = object:get_pos(), object:get_velocity()
+			local obj_yaw = object:get_yaw()
+			pos_no, pos_sum = pos_no + 1, vec_add(pos_sum, boid_pos)
+			sum_sin, sum_cos = sum_sin + sin(obj_yaw), sum_cos + cos(obj_yaw)
+			lift_no, lift_sum = lift_no + 1, lift_sum + vel.y
+			if not closest_pos
+			or vec_dist(pos, boid_pos) < vec_dist(pos, closest_pos) then
+				closest_pos = boid_pos
+			end
+		end
+	end
+	if not closest_pos then return end
+	local center = vec_divide(pos_sum, pos_no)
+	local lift = lift_sum / lift_no
+
+	local angle_sin, angle_cos
+	local radius = self.tracking_range * 0.5 or 4
+	local dist_factor = (radius - vec_dist(pos, closest_pos)) / radius
+
+	local alignment = atan2(sum_sin, sum_cos)
+	local seperation = dir2yaw(vec_dir(closest_pos, pos))
+	local cohesion = dir2yaw(vec_dir(pos, center))
+	if dist_factor > 0.9 then
+		seperation = interp_rad(alignment, seperation, 0.5)
+		angle_sin, angle_cos = sin(seperation), cos(seperation)
+	else
+		angle_sin, angle_cos = sin(cohesion), cos(cohesion)
+	end
+	local angle = atan2(angle_sin + sin(alignment), angle_cos + cos(alignment))
+
+	local dir = yaw2dir(angle)
+	dir.y = lift
+	return vector.normalize(dir), boids
+end
+
+-- Deprecated
 
 function creatura.get_boid_members(pos, radius, name)
 	local objects = minetest.get_objects_inside_radius(pos, radius)
@@ -71,7 +157,6 @@ function creatura.get_boid_members(pos, radius, name)
 		local object = objects[i]
 		if object:get_luaentity()
 		and object:get_luaentity().name == name then
-			object:get_luaentity().boid_heading = math.rad(random(360))
 			table.insert(members, object)
 		end
 	end
@@ -86,8 +171,6 @@ function creatura.get_boid_members(pos, radius, name)
 	return members
 end
 
--- Calculate Boid angles and offsets.
-
 function creatura.get_boid_angle(self, _boids, range)
 	local pos = self.object:get_pos()
 	local boids = _boids or creatura.get_boid_members(pos, range or 4, self.name)
@@ -127,9 +210,6 @@ function creatura.get_boid_angle(self, _boids, range)
 	local seperation = yaw + -(dir2yaw(dir2closest) - yaw)
 	local cohesion = dir2yaw(dir2center)
 	local params = {alignment}
-	if self.boid_heading then
-		table.insert(params, yaw + self.boid_heading)
-	end
 	if dist_2d(pos, closest_pos) < (self.boid_seperation or self.width * 3) then
 		table.insert(params, seperation)
 	elseif dist_2d(pos, center) > (#boids * 0.33) * (self.boid_seperation or self.width * 3) then
@@ -145,6 +225,5 @@ function creatura.get_boid_angle(self, _boids, range)
 	elseif math.abs(pos.y - closest_pos.y) > 1.5 * (self.boid_seperation or self.width * 3) then
 		table.insert(vert_params, vert_cohesion + (lift - vert_cohesion) * 0.1)
 	end
-	self.boid_heading = nil
 	return average_angle(params), average(vert_params)
 end

methods.lua

@@ -40,7 +40,7 @@ local dir2yaw = minetest.dir_to_yaw
 		texture = tex or "creatura_particle_red.png",
 		expirationtime = time or 0.1,
 		glow = 16,
-		size = 16
+		size = 24
 	})
 end]]
 
@@ -104,7 +104,7 @@ end]]
 end]]
 
 local get_node_def = creatura.get_node_def
-local get_node_height = creatura.get_node_height_from_def
+--local get_node_height = creatura.get_node_height_from_def
 
 function creatura.get_collision_ranged(self, dir, range)
 	local pos, yaw = self.object:get_pos(), self.object:get_yaw()
@@ -114,13 +114,17 @@ function creatura.get_collision_ranged(self, dir, range)
 	pos.y = pos.y + 0.01
 	dir = vec_normal(dir or yaw2dir(yaw))
 	yaw = dir2yaw(dir)
-	local ahead = vec_add(pos, vec_multi(dir, width))
+	local outset = math.floor(width)
+	if outset < 0.5 then outset = 0.5 end
+	local ahead = vec_add(pos, vec_multi(dir, outset))
+	local height_half = self.height * 0.5
+	local center_y = pos.y + height_half
 	-- Loop
 	local cos_yaw = cos(yaw)
 	local sin_yaw = sin(yaw)
 	local pos_x, pos_y, pos_z = ahead.x, ahead.y, ahead.z
 	local dir_x, dir_y, dir_z = dir.x, dir.y, dir.z
-	local dist
+	local danger = 0
 	local collision
 	for _ = 0, range or 4 do
 		pos_x = pos_x + dir_x
@@ -135,13 +139,14 @@ function creatura.get_collision_ranged(self, dir, range)
 			}
 			for y = 0, height, height / ceil(height) do
 				pos2.y = pos_y + y
-				local dist2 = vec_dist(pos, pos2)
-				if not dist
-				or dist2 < dist then
-					if pos2.y - pos_y > (self.stepheight or 1.1)
-					and get_node_def(pos2).walkable then
+				if pos2.y - pos_y > (self.stepheight or 1.1)
+				and get_node_def(pos2).walkable then
+					local dist_dngr = (height_half - abs(center_y - pos2.y)) / height_half
+					local field_dngr = vec_dot(dir, vec_normal(vec_dir(pos, pos2)))
+					local ttl_dngr = dist_dngr + field_dngr
+					if ttl_dngr > danger then
+						danger = ttl_dngr
 						collision = pos2
-						dist = dist2
 					end
 				end
 			end
@@ -192,7 +197,7 @@ local function get_avoidance_dir(self)
 		vel.y = 0
 		local vel_len = vec_len(vel) * (1 + (self.step_delay or 0))
 		local ahead = vec_add(pos, vec_normal(vel))
-		local avoidance_force = vector.subtract(ahead, col_pos)
+		local avoidance_force = vec_sub(ahead, col_pos)
 		avoidance_force.y = 0
 		avoidance_force = vec_multi(vec_normal(avoidance_force), (vel_len > 1 and vel_len) or 1)
 		return vec_dir(pos, vec_add(ahead, avoidance_force))
@@ -210,7 +215,7 @@ local steer_directions = {
 	vec_normal({x = -1, y = 0, z = 1})
 }
 
-function creatura.get_context_steering(self, goal, range)
+--[[function creatura.get_context_steering(self, goal, range)
 	local pos, vel = self.object:get_pos(), self.object:get_velocity()
 	if not pos then return end
 	local heading = vec_normal(vel)
@@ -246,7 +251,7 @@ function creatura.get_context_steering(self, goal, range)
 				local ahead = vec_add(pos, vec_multi(heading, self.width + dist2col))
 				local avd_force = vec_normal(vec_sub(ahead, collision))
 				dir.y = avd_force.y / 4
-				local dot_weight = vec_dot(vec_normal(dir2col), dir)
+				local dot_weight = vec_dot(vec_normal(dir2col), dir2goal)
 				local dist_weight = (range - dist2col) / range
 				interest = interest - dot_weight
 				danger = dist_weight
@@ -256,6 +261,62 @@ function creatura.get_context_steering(self, goal, range)
 		output_dir = vector.add(output_dir, vector.multiply(dir, score))
 	end
 	return output_dir
+end]]
+
+local function get_collision_single(pos)
+	local pos2 = {x = pos.x, y = pos.y, z = pos.z}
+	if get_node_def(pos2).walkable then
+		pos2.y = pos.y + 1
+		local col_max = get_node_def(pos2).walkable
+		pos2.y = pos.y - 1
+		local col_min = col_max and get_node_def(pos2).walkable
+		if col_min then
+			return pos
+		else
+			pos2.y = pos.y + 1
+			return pos2
+		end
+	end
+end
+
+function creatura.get_context_steering(self, goal, range)
+	local pos, yaw = self.object:get_pos(), self.object:get_yaw()
+	if not pos or not yaw then return end
+	range = range or 8; if range < 2 then range = 2 end
+	local width, height = self.width, self.height
+	local dir2goal = vec_normal(vec_dir(pos, goal))
+	local output_dir = {x = 0, y = 0, z = 0}
+	pos.y = (pos.y + height * 0.5)
+
+	local collision
+	local dir2col
+	local dir
+	for _, _dir in ipairs(steer_directions) do
+		dir = {x = _dir.x, y = 0, z = _dir.z}
+		local score = vec_dot(dir2goal, dir)
+		local interest = clamp(score, 0, 1)
+		local danger = 0
+		if interest > 0 then
+			if width <= 0.5
+			and height <= 1 then
+				collision = get_collision_single(vec_add(pos, dir))
+			else
+				_, collision = creatura.get_collision_ranged(self, dir, range)
+			end
+			if collision then
+				dir2col = vec_normal(vec_dir(pos, collision))
+				local dist2col = vec_dist(pos, collision) - width
+				dir.y = dir2col.y * -1
+				local dot_weight = vec_dot(dir2col, dir2goal)
+				local dist_weight = (range - dist2col) / range
+				interest = interest - dot_weight
+				danger = dist_weight
+			end
+		end
+		score = interest - danger
+		output_dir = vector.add(output_dir, vector.multiply(dir, score))
+	end
+	return output_dir
 end
 
 -------------
@@ -508,7 +569,7 @@ creatura.register_movement_method("creatura:context_based_steering", function(se
 		end
 		-- Calculate Movement
 		steer_timer = (steer_timer > 0 and steer_timer - self.dtime) or 0.25
-		steer_to = (steer_timer <= 0 and creatura.get_context_steering(self, goal, 2)) or steer_to
+		steer_to = (steer_timer <= 0 and creatura.get_context_steering(self, goal, 3)) or steer_to
 		local speed = abs(_self.speed or 2) * speed_factor or 0.5
 		local turn_rate = abs(_self.turn_rate or 5)
 		-- Apply Movement

settingtypes.txt

@@ -19,6 +19,9 @@ creatura_mapgen_spawn_interval (Mapgen Spawning Interval) int 5
 # How many Mobs can be a in a Mapblock before ABM spawning is blocked
 creatura_mapblock_limit (Max Mobs per Mapblock) int 99
 
+# Minimum distance to a player for ABM Spawning
+creatura_min_abm_dist (Minimum ABM Spawning Distance) int 32
+
 # Allotted time (in μs) per step for A* pathfinding (lower means less lag but slower pathfinding)
 creatura_a_star_alloted_time (A* Pathfinding Alloted time per step) int 500