2022-02-10 16:32:53 -08:00
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-----------
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-- Boids --
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-----------
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2022-08-27 20:07:53 -07:00
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local abs = math.abs
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2022-02-10 16:32:53 -08:00
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local random = math.random
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local function average(tbl)
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2022-06-16 14:57:06 -07:00
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local sum = 0
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for _,v in pairs(tbl) do -- Get the sum of all numbers in t
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sum = sum + v
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end
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return sum / #tbl
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2022-02-10 16:32:53 -08:00
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end
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local function average_angle(tbl)
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2022-06-16 14:57:06 -07:00
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local sum_sin, sum_cos = 0, 0
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for _, v in pairs(tbl) do
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sum_sin = sum_sin + math.sin(v)
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sum_cos = sum_cos + math.cos(v)
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end
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return math.atan2(sum_sin, sum_cos)
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2022-02-10 16:32:53 -08:00
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end
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local vec_dist = vector.distance
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local vec_dir = vector.direction
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local vec_add = vector.add
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local vec_normal = vector.normalize
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local vec_divide = vector.divide
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local function get_average_pos(vectors)
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2022-06-16 14:57:06 -07:00
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local sum = {x = 0, y = 0, z = 0}
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for _, vec in pairs(vectors) do sum = vec_add(sum, vec) end
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return vec_divide(sum, #vectors)
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2022-02-10 16:32:53 -08:00
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end
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local function dist_2d(pos1, pos2)
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2022-06-16 14:57:06 -07:00
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local a = vector.new(
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pos1.x,
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0,
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pos1.z
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)
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local b = vector.new(
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pos2.x,
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0,
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pos2.z
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)
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return vec_dist(a, b)
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2022-02-10 16:32:53 -08:00
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end
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local yaw2dir = minetest.yaw_to_dir
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local dir2yaw = minetest.dir_to_yaw
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-- Get Boid Members --
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-- This function scans within
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-- a set radius for potential
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-- boid members, and assigns
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-- a leader. A new leader
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-- is only assigned every 12
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-- seconds or if a new mob
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-- is in the boid.
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function creatura.get_boid_members(pos, radius, name)
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2022-06-16 14:57:06 -07:00
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local objects = minetest.get_objects_inside_radius(pos, radius)
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if #objects < 2 then return {} end
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local members = {}
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local max_boid = minetest.registered_entities[name].max_boids or 7
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for i = 1, #objects do
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if #members > max_boid then break end
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local object = objects[i]
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if object:get_luaentity()
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and object:get_luaentity().name == name then
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object:get_luaentity().boid_heading = math.rad(random(360))
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table.insert(members, object)
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end
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end
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2022-08-09 15:18:47 -07:00
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if #members > 1 then
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for _, object in ipairs(members) do
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local ent = object and object:get_luaentity()
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if ent then
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ent._movement_data.boids = members
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end
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end
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end
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2022-06-16 14:57:06 -07:00
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return members
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2022-02-10 16:32:53 -08:00
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end
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-- Calculate Boid angles and offsets.
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2022-06-16 14:57:06 -07:00
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function creatura.get_boid_angle(self, _boids, range)
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local pos = self.object:get_pos()
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local boids = _boids or creatura.get_boid_members(pos, range or 4, self.name)
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if #boids < 3 then return end
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local yaw = self.object:get_yaw()
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local lift = self.object:get_velocity().y
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-- Add Boid data to tables
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local closest_pos
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local positions = {}
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local angles = {}
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local lifts = {}
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for i = 1, #boids do
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local boid = boids[i]
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if boid:get_pos() then
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2022-08-27 20:07:53 -07:00
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local vel = boid:get_velocity()
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if boid ~= self.object
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and (abs(vel.x) > 0.1
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or abs(vel.z) > 0.1) then
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local boid_pos = boid:get_pos()
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table.insert(positions, boid_pos)
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table.insert(lifts, vec_normal(vel).y)
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2022-06-16 14:57:06 -07:00
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table.insert(angles, boid:get_yaw())
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if not closest_pos
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or vec_dist(pos, boid_pos) < vec_dist(pos, closest_pos) then
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closest_pos = boid_pos
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end
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end
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end
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end
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if #positions < 3 then return end
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local center = get_average_pos(positions)
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local dir2closest = vec_dir(pos, closest_pos)
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-- Calculate Parameters
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local alignment = average_angle(angles)
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center = vec_add(center, yaw2dir(alignment))
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local dir2center = vec_dir(pos, center)
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local seperation = yaw + -(dir2yaw(dir2closest) - yaw)
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local cohesion = dir2yaw(dir2center)
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local params = {alignment}
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if self.boid_heading then
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table.insert(params, yaw + self.boid_heading)
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end
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if dist_2d(pos, closest_pos) < (self.boid_seperation or self.width * 3) then
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table.insert(params, seperation)
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elseif dist_2d(pos, center) > (#boids * 0.33) * (self.boid_seperation or self.width * 3) then
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table.insert(params, cohesion)
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end
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-- Vertical Params
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local vert_alignment = average(lifts)
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local vert_seperation = (self.speed or 2) * -dir2closest.y
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local vert_cohesion = (self.speed or 2) * dir2center.y
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local vert_params = {vert_alignment}
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if math.abs(pos.y - closest_pos.y) < (self.boid_seperation or self.width * 3) then
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table.insert(vert_params, vert_seperation)
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elseif math.abs(pos.y - closest_pos.y) > 1.5 * (self.boid_seperation or self.width * 3) then
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table.insert(vert_params, vert_cohesion + (lift - vert_cohesion) * 0.1)
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end
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self.boid_heading = nil
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2022-08-05 17:42:37 -07:00
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return average_angle(params), average(vert_params)
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2022-02-10 16:32:53 -08:00
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end
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