mirror of
https://github.com/sbrl/Minetest-WorldEditAdditions.git
synced 2024-06-02 12:53:00 +00:00
124 lines
4.6 KiB
Lua
124 lines
4.6 KiB
Lua
local wea = worldeditadditions
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--- Parses a comma-separated side numbers list out into a list of numbers.
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-- @param list string The command separated list to parse.
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-- @returns number[] A list of side numbers.
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local function parse_sides_list(list)
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list = list:gsub("%s", "") -- Spaces are not permitted
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return wea.table.unique(wea.table.map(
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wea.split(list, ","),
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function(value) return tonumber(value) end
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))
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end
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function worldeditadditions.erode.river(heightmap_initial, heightmap, heightmap_size, region_height, params_custom)
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local params = {
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steps = 1, -- Number of rounds/passes of the algorithm to run
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lower_sides = "4,3", -- Cells with this many adjacent horizontal neighbours that are lower than the current pixel will be removed
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raise_sides = "4,3", -- Cells with this many adjacect horizontal neighbours that are higher than the current pixel will be filled in
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doraise = true, -- Whether to do raise operations or not
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dolower = true -- Whether to do lower operations or not
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}
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-- Apply the custom settings
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wea.table.apply(params_custom, params)
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params.lower_sides = parse_sides_list(params.lower_sides)
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params.raise_sides = parse_sides_list(params.raise_sides)
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local timings = {}
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local filled = 0
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local removed = 0
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for i=1,params.steps do
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-- print("[DEBUG:river] step ", i)
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-- wea.format.array_2d(heightmap, heightmap_size.x)
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local time_start = wea.get_ms_time()
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-- Store up changes to make and make them at the end of the step
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-- This is important, because decisions
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local fill = { } -- Indexes to add 1 to
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local remove = { } -- Indexes to take 1 away from
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for z = heightmap_size.z - 1, 0, -1 do
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for x = heightmap_size.x - 1, 0, -1 do
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local hi = z*heightmap_size.x + x
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local thisheight = heightmap[hi]
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-- print("[DEBUG:river] z", z, "x", x, "thisheight", thisheight)
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local height_up = heightmap[hi]
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local height_down = heightmap[hi]
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local height_left = heightmap[hi]
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local height_right = heightmap[hi]
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if x > 0 then height_left = heightmap[z*heightmap_size.x + x-1] end
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if x < heightmap_size.x - 1 then height_right = heightmap[z*heightmap_size.x + x+1] end
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if z > 0 then height_up = heightmap[(z-1)*heightmap_size.x + x] end
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if z < heightmap_size.z - 1 then height_down = heightmap[(z+1)*heightmap_size.x + x] end
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-- Whether this pixel is on the edge
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local isedge = x <= 0
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or z <= 0
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or x >= heightmap_size.x - 1
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or z >= heightmap_size.z - 1
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local sides_higher = 0 -- Number of sides higher than this pixel
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local sides_lower = 0 -- Number of sides lower than this pixel
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if not isedge then
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if height_down > thisheight then sides_higher = sides_higher + 1 end
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if height_up > thisheight then sides_higher = sides_higher + 1 end
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if height_left > thisheight then sides_higher = sides_higher + 1 end
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if height_right > thisheight then sides_higher = sides_higher + 1 end
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if height_down < thisheight then sides_lower = sides_lower + 1 end
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if height_up < thisheight then sides_lower = sides_lower + 1 end
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if height_left < thisheight then sides_lower = sides_lower + 1 end
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if height_right < thisheight then sides_lower = sides_lower + 1 end
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end
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-- Perform an action, but only if we're not on the edge
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-- This is important, as we can't accurately tell how many
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-- adjacent neighbours a pixel on the edge has.
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local action = "none"
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if not isedge then
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if sides_higher > sides_lower then
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for i,sidecount in ipairs(params.raise_sides) do
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if sidecount == sides_higher then
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action = "fill"
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break
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end
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end
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else
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for i,sidecount in ipairs(params.lower_sides) do
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if sidecount == sides_lower then
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action = "remove"
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break
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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 action == "fill" and params.doraise then
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table.insert(fill, hi)
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filled = filled + 1
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elseif action == "remove" and params.dolower then
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table.insert(remove, hi)
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removed = removed + 1
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end
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-- print("[DEBUG:river] sides_higher", sides_higher, "sides_lower", sides_lower, "action", action)
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-- wea.format.array_2d(heightmap, heightmap_size.x)
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end
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end
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for i,hi in ipairs(fill) do
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heightmap[hi] = heightmap[hi] + 1
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end
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for i,hi in ipairs(remove) do
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heightmap[hi] = heightmap[hi] - 1
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end
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table.insert(timings, wea.get_ms_time() - time_start)
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end
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return true, params.steps.." steps made, raising "..filled.." and lowering "..removed.." columns in "..wea.format.human_time(wea.sum(timings)).." (~"..wea.format.human_time(wea.average(timings)).." per step)"
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end
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