Improved biter spawning algorithm (#408)

* Improved biter spawning algorithm

* HAIL HYDRA, biter hell

map_gen/Diggy/Config.lua

@@ -36,7 +36,7 @@ local Config = {
                 character_inventory_slots_bonus = 1000,
                 character_running_speed_modifier = 2,
                 starting_items = {
-                    {name = 'modular-armor', count = 1},
+                    {name = 'power-armor-mk2', count = 1},
                     {name = 'submachine-gun', count = 1},
                     {name = 'uranium-rounds-magazine', count = 200},
                 },
@@ -113,22 +113,28 @@ local Config = {
             minimal_treasure_chest_distance = 25,
 
             -- chances to receive a coin when mining
-            mining_artefact_chance = 0.10,
-            mining_artefact_amount = {min = 1, max = 4},
+            mining_coin_chance = 0.10,
+            mining_coin_amount = {min = 1, max = 4},
 
             -- lets you set the coin modifiers for aliens
             -- the modifier value increases the upper random limit that biters can drop
             alien_coin_modifiers = {
-                ['small-biter'] = 1,
-                ['small-spitter'] = 1,
-                ['medium-biter'] = 2,
-                ['medium-spitter'] = 2,
-                ['big-biter'] = 4,
-                ['big-spitter'] = 4,
-                ['behemoth-biter'] = 6,
-                ['behemoth-spitter'] = 6,
+                ['small-biter'] = 2,
+                ['small-spitter'] = 2,
+                ['small-worm'] = 2,
+                ['medium-biter'] = 3,
+                ['medium-spitter'] = 3,
+                ['medium-worm'] = 3,
+                ['big-biter'] = 5,
+                ['big-spitter'] = 5,
+                ['big-worm'] = 5,
+                ['behemoth-biter'] = 7,
+                ['behemoth-spitter'] = 7,
             },
 
+            -- chance of aliens dropping coins between 0 and 1, where 1 is 100%
+            alien_coin_drop_chance = 0.30,
+
             -- shows the chest locations, only use when debugging
             display_chest_locations = false,
 
@@ -285,7 +291,30 @@ local Config = {
             alien_minimum_distance = 40,
 
             -- chance of spawning aliens when mining
-            alien_probability = 0.07,
+            alien_probability = 0.05,
+
+            -- spawns the following units when they die. To disable change it to:
+            --hail_hydra = nil,
+            -- any non-rounded number will turn into a chance to spawn an additional alien
+            -- example: 2.5 would spawn 2 for sure and 50% chance to spawn one additionally
+            hail_hydra = {
+                -- spitters
+                ['small-spitter'] = {['small-worm-turret'] = 0.4},
+                ['medium-spitter'] = {['medium-worm-turret'] = 0.4},
+                ['big-spitter'] = {['big-worm-turret'] = 0.4},
+                ['behemoth-spitter'] = {['big-worm-turret'] = 0.6},
+
+                -- biters
+                ['medium-biter'] = {['small-biter'] = 1.7},
+                ['big-biter'] = {['medium-biter'] = 1.7},
+                ['behemoth-biter'] = {['big-biter'] = 1.7},
+                ['behemoth-biter'] = {['big-biter'] = 1.7},
+
+                -- worms
+                ['small-worm-turret'] = {['small-biter'] = 2.5},
+                ['medium-worm-turret'] = {['small-biter'] = 2.5, ['medium-biter'] = 0.5},
+                ['big-worm-turret'] = {['small-biter'] = 3.5, ['medium-biter'] = 1, ['big-biter'] = 0.5},
+            },
         },
 
         -- controls the market and buffs

map_gen/Diggy/Feature/AlienSpawner.lua

@@ -4,31 +4,136 @@
 
 -- dependencies
 local Event = require 'utils.event'
+local Global = require 'utils.global'
+local Token = require 'utils.global_token'
+local Task = require 'utils.task'
 local AlienEvolutionProgress = require 'map_gen.Diggy.AlienEvolutionProgress'
 local Debug = require 'map_gen.Diggy.Debug'
 local Template = require 'map_gen.Diggy.Template'
-local insert = table.insert
 local random = math.random
+local floor = math.floor
+local ceil = math.ceil
+local insert = table.insert
+local raise_event = script.raise_event
 
 -- this
 local AlienSpawner = {}
 
-local function spawn_alien(surface, x, y)
-    local enemy_force = game.forces.enemy
-    local enemy_force_evolution = enemy_force.evolution_factor
+local alien_size_chart = {}
+
+Global.register_init({
+    alien_size_chart = alien_size_chart,
+}, function(tbl)
+    for name, prototype in pairs(game.entity_prototypes) do
+        if prototype.type == 'unit' and prototype.subgroup.name == 'enemies' then
+            tbl.alien_size_chart[name] = {
+                name = name,
+                collision_box = prototype.collision_box
+            }
+        end
+    end
+end, function(tbl)
+    alien_size_chart = tbl.alien_size_chart
+end)
+
+---Triggers mining at the collision_box of the alien, to free it
+local do_alien_mining = Token.register(function(params)
+    local surface = params.surface
+    local create_entity = surface.create_entity
+    local find_non_colliding_position = surface.find_non_colliding_position
+    local find_entities_filtered = surface.find_entities_filtered
+
+    for _, area in ipairs(params.positions_to_mine) do
+        local rocks = find_entities_filtered({area = area, name = {'sand-rock-big', 'rock-huge'}})
+
+        if (0 == #rocks) then
+            break
+        end
+
+        for _, rock in pairs(rocks) do
+            raise_event(defines.events.on_entity_died, {entity = rock})
+            rock.destroy()
+        end
+    end
+
+    for _, prototype in ipairs(params.locations_to_spawn) do
+        -- amount is not used for aliens prototypes, it just carries along in the params
+        local amount = prototype.amount
+        while amount > 0 do
+            prototype.position = find_non_colliding_position(prototype.name, prototype.position, 2, 0.4) or prototype.position
+            create_entity(prototype)
+            amount = amount - 1
+        end
+    end
+end)
+
+---Spawns aliens given the parameters.
+---@param aliens table index is the name, value is the amount of biters to spawn
+---@param force LuaForce of the biters
+---@param surface LuaSurface to spawn on
+---@param x number
+---@param y number
+local function spawn_aliens(aliens, force, surface, x, y)
     local position = {x = x, y = y}
-    local biters = AlienEvolutionProgress.getBitersByEvolution(random(1, 2), enemy_force_evolution)
-    local spitters = AlienEvolutionProgress.getSpittersByEvolution(random(1, 2), enemy_force_evolution)
+    local count_tiles_filtered = surface.count_tiles_filtered
+    local areas_to_mine = {}
+    local locations_to_spawn = {}
 
-    local units = {}
-    for name, amount in pairs(biters) do
-        insert(units, {name = name, position = position, force = enemy_force, amount = amount})
-    end
-    for name, amount in pairs(spitters) do
-        insert(units, {name = name, position = position, force = enemy_force, amount = amount})
+    for name, amount in pairs(aliens) do
+        local size_data = alien_size_chart[name]
+        if not size_data then
+            Debug.print_position(position, 'Unable to find prototype data for ' .. name)
+            break
         end
 
-    Template.units(surface, units, 1.5, 'small-biter')
+        local locations_to_scan = {
+            {x = 0, y = -1.5}, -- up
+            {x = 1.5, y = 0}, -- right
+            {x = 0, y = 1.5}, -- bottom
+            {x = -1.5, y = 0}, -- left
+        }
+
+        local collision_box = size_data.collision_box
+        local left_top_x = collision_box.left_top.x * 1.6
+        local left_top_y = collision_box.left_top.y * 1.6
+        local right_bottom_x = collision_box.right_bottom.x * 1.6
+        local right_bottom_y = collision_box.right_bottom.y * 1.6
+
+        for _, direction in ipairs(locations_to_scan) do
+            local x_center = direction.x + x
+            local y_center = direction.y + y
+
+            -- *_center indicates the offset center relative to the location where it should spawn
+            -- the area is composed of the bounding_box of the alien with a bigger size so it has space to move
+            local offset_area = {
+                left_top = {
+                    x = floor(x_center + left_top_x),
+                    y = floor(y_center + left_top_y),
+                },
+                right_bottom = {
+                    x = ceil(x_center + right_bottom_x),
+                    y = ceil(y_center + right_bottom_y),
+                },
+            }
+
+            -- can't spawn properly if void is present
+            if count_tiles_filtered({area = offset_area, name = 'out-of-map'}) == 0 then
+                insert(areas_to_mine, offset_area)
+                insert(locations_to_spawn, {name = name, position = {x = x_center, y = y_center}, force = force, amount = amount})
+                break
+            end
+        end
+    end
+
+    -- can't do mining in the same tick as it would invalidate the rock just mined and there
+    -- is no way to distinguish them as multiple can occupy the same position
+    if #locations_to_spawn > 0 then
+        Task.set_timeout_in_ticks(1, do_alien_mining, {
+            surface = surface,
+            positions_to_mine = areas_to_mine,
+            locations_to_spawn = locations_to_spawn,
+        })
+    end
 end
 
 --[[--
@@ -36,19 +141,68 @@ end
 ]]
 function AlienSpawner.register(config)
     local alien_minimum_distance_square = config.alien_minimum_distance ^ 2
+    local alien_probability = config.alien_probability
+    local hail_hydra = config.hail_hydra
+
+    if hail_hydra then
+        Event.add(defines.events.on_entity_died, function (event)
+            local entity = event.entity
+            local name = entity.name
+
+            local force
+            local position
+            local surface
+            local create_entity
+            local find_non_colliding_position
+
+            for alien, hydras in pairs(hail_hydra) do
+                if name == alien then
+                    for hydra_spawn, amount in pairs(hydras) do
+                        local extra_chance = amount % 1
+                        if extra_chance > 0 then
+                            if random() <= extra_chance then
+                                amount = ceil(amount)
+                            else
+                                amount = floor(amount)
+                            end
+                        end
+
+                        while amount > 0 do
+                            force = force or entity.force
+                            position = position or entity.position
+                            surface = surface or entity.surface
+                            create_entity = create_entity or surface.create_entity
+                            find_non_colliding_position = find_non_colliding_position or surface.find_non_colliding_position
+                            position = find_non_colliding_position(hydra_spawn, position, 2, 0.4) or position
+                            create_entity({name = hydra_spawn, force = force, position = position})
+                            amount = amount - 1
+                        end
+                    end
+                    break
+                end
+            end
+        end)
+    end
 
     Event.add(Template.events.on_void_removed, function (event)
-        game.forces.enemy.evolution_factor = game.forces.enemy.evolution_factor + 0.0000012
+        local force = game.forces.enemy
+        local evolution_factor = force.evolution_factor
+        force.evolution_factor = evolution_factor + 0.0000012
 
         local position = event.position
         local x = position.x
         local y = position.y
 
-        if (x * x + y * y < alien_minimum_distance_square or config.alien_probability < random()) then
+        if (x * x + y * y < alien_minimum_distance_square or alien_probability < random()) then
             return
         end
 
-        spawn_alien(event.surface, x, y)
+        local aliens = AlienEvolutionProgress.getBitersByEvolution(random(1, 2), evolution_factor)
+        for name, amount in pairs(AlienEvolutionProgress.getSpittersByEvolution(random(1, 2), evolution_factor)) do
+            aliens[name] = amount
+        end
+
+        spawn_aliens(aliens, force, event.surface, x, y)
     end)
 end
 

map_gen/Diggy/Feature/ArtefactHunting.lua

@@ -165,25 +165,21 @@ function ArtefactHunting.register(config)
 
     ScoreTable.reset('Collected coins')
 
+    local alien_coin_drop_chance = config.alien_coin_drop_chance
+
     Event.add(defines.events.on_entity_died, function (event)
         local entity = event.entity
         local force = entity.force
 
-        if force.name ~= 'enemy' then
-            return
-        end
-
-        local cause = event.cause
-
-        if not cause or cause.type ~= 'player' or not cause.valid then
+        if force.name ~= 'enemy' or random() > alien_coin_drop_chance then
             return
         end
 
         local modifier = modifiers[entity.name] or 1
-        local evolution_multiplier = force.evolution_factor * 11
+        local evolution_multiplier = force.evolution_factor
         local count = random(
-            ceil(2 * evolution_multiplier * 0.1),
-            ceil(5 * (evolution_multiplier * evolution_multiplier + modifier) * 0.1)
+            ceil(2 * evolution_multiplier * modifier),
+            ceil(5 * evolution_multiplier * modifier)
         )
 
         entity.surface.create_entity({
@@ -207,11 +203,11 @@ function ArtefactHunting.register(config)
             return
         end
 
-        if random() > config.mining_artefact_chance then
+        if random() > config.mining_coin_chance then
             return
         end
 
-        local count = random(config.mining_artefact_amount.min, config.mining_artefact_amount.max)
+        local count = random(config.mining_coin_amount.min, config.mining_coin_amount.max)
         local player_index = event.player_index
 
         Game.get_player_by_index(player_index).insert({name = 'coin', count = count})

map_gen/Diggy/Feature/DiggyHole.lua

@@ -236,14 +236,16 @@ function DiggyHole.register(config)
         local entity = event.entity
         local name = entity.name
 
+        if entity.health ~= 0 then
+            return
+        end
+
         if name ~= 'sand-rock-big' and name ~= 'rock-huge' then
             return
         end
 
-        if entity.health == 0 then
         raise_event(defines.events.on_entity_died, {entity = entity, cause = event.cause, force = event.force})
         entity.destroy()
-        end
     end)
 
     local enable_digging_warning = config.enable_digging_warning

map_gen/Diggy/Template.lua

@@ -140,39 +140,6 @@ function Template.insert(surface, tiles, entities)
     end
 end
 
---[[--
-    Designed to spawn aliens, uses find_non_colliding_position.
-
-    @see LuaSurface.entity
-
-    @param surface LuaSurface to put the tiles and entities on
-    @param units table of entities as required by create_entity
-    @param non_colliding_distance int amount of tiles to scan around original position in case it's already taken
-    @param generic_unit_name_for_spawn_size String allows setting a custom unit name for spawn size, will overwrite the actual
-]]
-function Template.units(surface, units, non_colliding_distance, generic_unit_name_for_spawn_size)
-    non_colliding_distance = non_colliding_distance or 1
-    generic_unit_name_for_spawn_size = generic_unit_name_for_spawn_size or 'player'
-
-    local create_entity = surface.create_entity
-    local position
-
-    for _, entity in pairs(units) do
-        position = position or surface.find_non_colliding_position(
-            generic_unit_name_for_spawn_size,
-            entity.position, non_colliding_distance,
-            0.5
-        )
-
-        if (nil ~= position) then
-            entity.position = position
-            create_entity(entity)
-        elseif (nil == create_entity(entity)) then
-            Debug.print_position(entity.position, "Failed to spawn '" .. entity.name .. "'")
-        end
-    end
-end
-
 --[[--
     Designed to spawn resources.