Mirrorlandia_minetest/Minetest-WorldEditAdditions
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//erode: initial river algorithm implementation

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Starbeamrainbowlabs 2021-05-30 00:02:21 +01:00
parent 17b8f8a555
commit 9ecdd01914
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GPG Key ID: 1BE5172E637709C2
2 changed files with 115 additions and 2 deletions
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17
worldeditadditions/lib/erode/erode.lua
View File

@ -24,14 +24,27 @@ function worldeditadditions.erode.run(pos1, pos2, algorithm, params)
-- worldeditadditions.format.array_2d(heightmap, heightmap_size.x)
local success, msg, stats
if algorithm == "snowballs" then
success, msg = worldeditadditions.erode.snowballs(heightmap, heightmap_eroded, heightmap_size, region_height, params)
success, msg = worldeditadditions.erode.snowballs(
heightmap, heightmap_eroded,
heightmap_size,
region_height,
params
)
if not success then return success, msg end
elseif algorithm == "river" then
success, msg = worldeditadditions.erode.river(
heightmap, heightmap_eroded,
heightmap_size,
region_height,
params
)
if not success then return success, msg end
else
-- FUTURE: Add a new "river" algorithm here that:
-- * Fills in blocks that are surrounded on more than 3 horizontal sides
-- * Destroys blocks that have no horizontal neighbours
-- A bit like cellular automata actually.
return false, "Error: Unknown algorithm '"..algorithm.."'. Currently implemented algorithms: snowballs (2d; hydraulic-like). Ideas for algorithms to implement are welcome!"
return false, "Error: Unknown algorithm '"..algorithm.."'. Currently implemented algorithms: snowballs (2d; hydraulic-like), river (2d; cellular automata-like; fills potholes and lowers towers). Ideas for algorithms to implement are welcome!"
end
success, stats = worldeditadditions.apply_heightmap_changes(

100
worldeditadditions/lib/erode/river.lua Normal file
View File

@ -0,0 +1,100 @@
local wea = worldeditadditions
--- Parses a comma-separated side numbers list out into a list of numbers.
-- @param list string The command separated list to parse.
-- @returns number[] A list of side numbers.
local function parse_sides_list(list)
list = list:gsub("%s", "") -- Spaces are not permitted
return wea.table_unique(wea.table_map(
wea.split(list, ","),
function(value) return tonumber(value) end
))
end
function worldeditadditions.erode.river(heightmap_initial, heightmap, heightmap_size, region_height, params_custom)
local params = {
steps = 1, -- Number of rounds/passes of the algorithm to run
remove_sides = "0,1", -- Cells with this many adjacent horizontal neighbours will be removed
fill_sides = "4,3" -- Cells with this many adjaect horizontal neighbours will be filled in
}
-- Apply the custom settings
wea.table_apply(params_custom, params)
params.remove_sides = parse_sides_list(params.remove_sides)
params.fill_sides = parse_sides_list(params.fill_sides)
local timings = {}
local filled = 0
local removed = 0
for i=1,params.steps do
local time_start = wea.get_ms_time()
for z = heightmap_size.z - 1, 0, -1 do
for x = heightmap_size.x - 1, 0, -1 do
local hi = z*heightmap_size.x + x
local thisheight = heightmap[hi]
local sides = 0
local adjacent_heights = { }
if x > 0 then
table.insert(adjacent_heights, heightmap[z*heightmap_size.x + x-1])
if heightmap[z*heightmap_size.x + x-1] >= thisheight then
sides = sides + 1
end
end
if x < heightmap_size.x - 1 then
table.insert(adjacent_heights, heightmap[z*heightmap_size.x + x+1])
if heightmap[z*heightmap_size.x + x+1] >= thisheight then
sides = sides + 1
end
end
if z > 0 then
table.insert(adjacent_heights, heightmap[(z-1)*heightmap_size.x + x])
if heightmap[(z-1)*heightmap_size.x + x] >= thisheight then
sides = sides + 1
end
end
if z < heightmap_size.z - 1 then
table.insert(adjacent_heights, heightmap[(z+1)*heightmap_size.x + x])
if heightmap[(z+1)*heightmap_size.x + x] >= thisheight then
sides = sides + 1
end
end
local action = "none"
for i,sidecount in ipairs(params.fill_sides) do
if sidecount == sides then
action = "fill"
break
end
end
for i,sidecount in ipairs(params.remove_sides) do
if sidecount == sides then
action = "remove"
break
end
end
if action == "fill" then
local above_us = wea.table_filter(adjacent_heights,
function(height) return height > thisheight end
)
local above_us_next = wea.min(above_us)
heightmap[hi] = above_us_next
filled = filled + 1
elseif action == "remove" then
local below_us = wea.table_filter(adjacent_heights,
function(height) return height < thisheight end
)
local below_us_next = wea.max(below_us)
heightmap[hi] = below_us_next
removed = removed + 1
end
end
end
table.insert(timings, wea.get_ms_time() - time_start)
end
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)"
end