RedMew/map_gen/presets/diagonal_ribbon.lua

--[[
Inspired/copied from Beach/Double beach by GrilledHam
Creates a diagonal, wavy ribbon world with only tiles. Vanilla ore and biter generation are unaffected.

Post-mortum analysis after 2018-11-15 run:
Exchange string used was: >>>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<<<
With seed: 2963296099
The players expanded the base easily and had too much access to resources. The biter frequency should be increased and the ore richness and/or size decreased.
There was a lot of space in the North-South direction for building, so play_area_width should be turned down significantly.
]]--
local b = require 'map_gen.shared.builders'
local perlin = require 'map_gen.shared.perlin_noise'
local Global = require 'utils.global'
local math = require 'utils.math'

-- A "very small" starting area is advised at the default 100 width.
local play_area_width = 100 -- The approximate width of the play area
local oob_tile = 'out-of-map' -- The tiles that make up the out of bounds/world border. Recommended are out-of-map or water.

local oob_width = 233
local oob_width_inv = math.tau / oob_width

-- Perlin options
local noise_variance = 0.020 --The lower this number the smoother the curve is gonna be
local oob_noise_level = 15.25 --Factor for the magnitude of the curve

-- Leave nil and they will be set based on the map seed.
local perlin_seed_1 = nil
local perlin_seed_2 = nil

Global.register_init(
    {},
    function(tbl)
        local seed = game.surfaces[1].map_gen_settings.seed
        tbl.perlin_seed_1 = perlin_seed_1 or seed
        tbl.perlin_seed_2 = perlin_seed_2 or seed * 2
    end,
    function(tbl)
        perlin_seed_1 = tbl.perlin_seed_1
        perlin_seed_2 = tbl.perlin_seed_2
    end
)

local function oob_shape(x, y)
    local p = perlin.noise(x * noise_variance, y * noise_variance, perlin_seed_2) * oob_noise_level
    p = p + math.sin(x * oob_width_inv + 179) * 15
    return p > y
end

-- Turn the tiles included in the out of bounds to the oob tile.
oob_shape = b.change_tile(oob_shape, true, oob_tile)

-- Offset the oob from the middle of the map/playing area
oob_shape = b.translate(oob_shape, 0, -(play_area_width/2))

--[[ Make up the map from 3 components: the oob shape we created (which covers the NW), a copy of the oob shape which is
    flipped (to cover the SE) and then translated so that the crests and valleys of the noise creates a nice wave.
    Lastly, any part of the map that isn't in oob_shape or the oob_copy is filled by full_shape which just passes the
    vanilla mapgen through. ]]--
local map = b.any {oob_shape, b.translate(b.flip_y(oob_shape), (oob_width/2), 0), b.full_shape}

map = b.rotate(map, math.rad(45))

return map