Biter Attack Test Script

/c
Settings = function()
	--[[
		Advised to use max group size of 200 or less to avoid them getting in each others way too much. when biter group is attacked each biter targets a random targets, so they get in each others way breaking pack formation. could reduce collision box size to 40% like Rampent?
		More than 10 groups total in a wave will tend to loose formation and partially form in to a mass single group column, rather than hold the shape. built in AI UPS protection.
		If you want more than 10 groups at a time call the command after each wave has cleared the spawn area or from a different side?
	]]
	_biterCount = 1000
	_biterMaxGroupSize = 100
	_biterSpawnTilesLeftOfPlayer = 150
	_biterWaveGroupsWide = 5
end

TriggerBiterGroup = function()
	_surface = game.player.surface
	_maxBiterGroups = math.ceil(_biterCount / _biterMaxGroupSize)
	if _maxBiterGroups < _biterWaveGroupsWide then
		_biterWaveGroupsWide = _maxBiterGroups
	end
	_biterGroupSize = math.ceil(_biterCount / _maxBiterGroups)
	_biterGroupTileWidth = 20
	_biterGroupTileLength = math.sqrt(_biterMaxGroupSize)
	local groupStartPos = FindBiterGatherPoint()
	if _maxBiterGroups > 20 then
		game.print("too many attack groups will lag the game - stopped")
		return
	end

	local waveWidthCount = 0
	local waveDepthCount = 0
	for i=1, _maxBiterGroups do
		local thisGroupStartPos = {
			x = groupStartPos.x - (waveDepthCount * 6 * _biterGroupTileLength),
			y = groupStartPos.y + (waveWidthCount * _biterGroupTileWidth)
		}

		local biterGroup = CreateBiterGroup(thisGroupStartPos)
		SpawnBitersInGroup(biterGroup, thisGroupStartPos, _biterGroupSize)
		BiterGroupAttackMoveArea(biterGroup, FindMoveTarget(waveWidthCount, waveDepthCount), FindAttackAreaTarget(i))
		biterGroup.start_moving()

		waveWidthCount = waveWidthCount + 1
		if waveWidthCount == _biterWaveGroupsWide then
			waveWidthCount = 0
			waveDepthCount = waveDepthCount + 1
		end
	end
end

FindBiterGatherPoint = function()
	return {
		x = game.player.position.x - _biterSpawnTilesLeftOfPlayer,
		y = game.player.position.y - ((_biterWaveGroupsWide * _biterGroupTileWidth) / 2)
	}
end

FindMoveTarget = function(groupWidthCount, groupDepthCount)
	return {
		x = game.player.position.x + (groupDepthCount),
		y = game.player.position.y - ((_biterWaveGroupsWide * _biterGroupTileWidth) / 2) + (groupWidthCount * _biterGroupTileWidth)
	}
end

FindAttackAreaTarget = function(groupCount)
	return {
		x = game.player.position.x + groupCount,
		y = game.player.position.y
	}
end

CreateBiterGroup = function(groupPosition)
	return _surface.create_unit_group{position = groupPosition, force = game.forces["enemy"]}
end

SpawnBitersInGroup = function(unitGroup, spawnCenterPos, groupSize)
	local biterType = "small-biter"
	for i=1, groupSize do
		local spawnPos = _surface.find_non_colliding_position(biterType, spawnCenterPos, 0, 1)
		local biter = _surface.create_entity{
			name = biterType,
			position = spawnPos,
			force = game.forces["enemy"]
		}
		if not biter then
			game.print("creation of biter" .. i .. "failed")
		else
			unitGroup.add_member(biter)
		end
	end
end

GetBiterGroupAttackAreaCommand = function(targetPos)
	return {
		type = defines.command.attack_area,
		destination = targetPos,
		radius = 10,
		distraction = defines.distraction.by_anything
	}
end

GetBiterGroupMoveCommand = function(moveToPos)
	return {
		type = defines.command.go_to_location,
		destination = moveToPos,
		distraction = defines.distraction.by_anything
	}
end

BiterGroupAttackMoveArea = function(unitGroup, moveToPos, targetPos)
	local command = {
		type = defines.command.compound,
		structure_type = defines.compound_command.return_last,
		commands = {
			GetBiterGroupMoveCommand(moveToPos),
			GetBiterGroupAttackAreaCommand(targetPos)
		}
	}
	unitGroup.set_command(command)
end

Settings()
TriggerBiterGroup()