## Diamond Square Procedural Map Generation

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darkfrei
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Joined: Sat Feb 08, 2020 11:09 pm

### Re: Diamond Square Procedural Map Generation

Gunroar:Cannon() wrote: Thu Jun 24, 2021 10:33 pm The map always seems incomplete, even at a high field.
I'm not familiar with this diamond-square, is there a possible way for me to show more of the map in a smaller area?
We can make chunks:

A chunk is a square (for example size 32 tiles [with sides 33x33]).
If the agent/player is in the chunk, then we are need to check neighbour chunks.
If neighbour chunks don't exist, create them. Don't overwrite existing pixels, but take them for interpolation.

So, chunk [0, 0] with size 32 has verticles: {{0,0},{32,0},{0,32},{32,32}}, the next one is [1, 0] with {{32,0},{64,0},{32,32},{64,32}}.

Note that we starting from 0 and from 0 to 32 is 33 tiles. The next chunk has one tile overlap: from 32 to 64 is also 33 tiles.
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Gunroar:Cannon()
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### Re: Diamond Square Procedural Map Generation

Oh, thnx. There's no option to change the frequency then?
Why can't pirates code in lua? Because they spend to much time at C!

-It might look like nonsense but there's so much proof.
-Some more if you pls... .
It has to be real then, all that talk about the end .
-How to be saved
pgimeno
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Joined: Sun Oct 18, 2015 2:58 pm

### Re: Diamond Square Procedural Map Generation

You can bandpass the images; basically, to apply a certain degree of blur (to reduce the higher frequencies), and to subtract a blurred version of it to another certain degree of blur (to reduce the lower frequencies). But blurring is slow. Also, you lose the original values at the vertices, so the method is not seamless when working in chunks.

I've done that with gimp, which has this method in Filters > Render > Clouds > Plasma (but you have to separate the R, G and B channels afterwards with Colours > Components > Decompose). The result was pretty convincing as noise.
Gunroar:Cannon()
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### Re: Diamond Square Procedural Map Generation

Hey, while experimenting, I made map_n 8 (roughness still 2) then kept chunk_size constant at 2^5 and that made a nice zoomed out map...but I had to make the default value of max to one and min to zero in get_random in case they were nil and that causes small holes in the map at some points. It really looks perfect if it wasn't for that fact. Any fix?
Why can't pirates code in lua? Because they spend to much time at C!

-It might look like nonsense but there's so much proof.
-Some more if you pls... .
It has to be real then, all that talk about the end .
-How to be saved
darkfrei
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Posts: 393
Joined: Sat Feb 08, 2020 11:09 pm

### Re: Diamond Square Procedural Map Generation

Gunroar:Cannon() wrote: Sat Jul 31, 2021 6:17 pm Hey, while experimenting, I made map_n 8 (roughness still 2) then kept chunk_size constant at 2^5 and that made a nice zoomed out map...but I had to make the default value of max to one and min to zero in get_random in case they were nil and that causes small holes in the map at some points. It really looks perfect if it wasn't for that fact. Any fix?
Show the screenshot, the code and where is the problem. Normally this function gives the middle value.
Falling in LÖVE
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Gunroar:Cannon()
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Posts: 519
Joined: Thu Dec 10, 2020 1:57 am

### Re: Diamond Square Procedural Map Generation

It's easy to recreate. Just make chunk_size = 2^5 in load function and map_n = 8 in love.load
main.lua

Code: Select all

-- License CC0 (Creative Commons license) (c) darkfrei, 2021

get_color = require ('sea-mountain-colors')
width, height = love.graphics.getDimensions( )

map = {}

map_size = 2^map_n + 1 -- 1025
chunk_size = 2^5--map_size - 1
roughness = 2

local corners = {{i=1,j=1}, {i=map_size,j=1}, {i=map_size,j=map_size}, {i=1,j=map_size}}

for _, corner in pairs (corners) do
local i, j = corner.i, corner.j
local value = math.random ()
value = 0.5-0.5*math.cos(value*math.pi)
map[i] = map[i] or {}
map[i][j] = value
end

states = {square = 'square', diamond = 'diamond'}
state = states.square

pause = false
end

local ddwidth, ddheight = love.window.getDesktopDimensions( display )
if ddheight > 1080 then
print('ddheight: ' .. ddheight)
love.window.setMode(1920, 1080, {resizable=true, borderless=false})
else
love.window.setMode(ddwidth, ddheight-200, {resizable=true, borderless=false})
end

map_n = 8
end

update = {}

function get_value (i, j)
if map[i] and map[i][j] then
return map[i][j]
end
end

function get_random (min, max)
max = max or 1 min = min or 0
local r = 4*(math.random ()-0.5)^3 + 0.5
--	https://www.desmos.com/calculator/toxjtsovev
return min + r*(max-min)
end

function get_square_value (i, j, half)
local value = 0
local n = 0
local min, max
for _, corner in pairs ({{i=i, j=j}, {i=i+chunk_size, j=j}, {i=i, j=j+chunk_size}, {i=i+chunk_size, j=j+chunk_size}}) do
local v = get_value (corner.i, corner.j)
if v then
min = min and math.min (min, v) or v
max = max and math.max (max, v) or v
value = value + v
n = n + 1
end
end
return value/n, min, max
end

update.square = function ()
local half = chunk_size/2
for i = 1, map_size-1, chunk_size do
for j = 1, map_size-1, chunk_size do
local value, min, max = get_square_value (i, j, half)
map[i+half] = map[i+half] or {}
map[i+half][j+half] = get_random (min, max)
end
end

state = states.diamond
end

function get_diamond_value (i, j, half)
local value = 0
local n = 0
local min, max
for _, corner in pairs ({{i=i, j=j-half}, {i=i+half, j=j}, {i=i, j=j+half}, {i=i-half, j=j}}) do
local v = get_value (corner.i, corner.j)
if v then
min = min and math.min (min, v) or v
max = max and math.max (max, v) or v
value = value + v
n = n + 1
end
end
return value/n, min, max
end

update.diamond = function ()
local half = chunk_size/2
for i = 1, map_size, half do
--		for j = 1, map_size-1, chunk_size do
for j = (i+half)%chunk_size, map_size, chunk_size do
--			print ('i: '..i .. ' j:'.. j)
--			if (i + j)%half == 0 then
local value, min, max = get_diamond_value (i, j, half)
map[i] = map[i] or {}
map[i][j] = get_random (min, max)
--			end
end
end

chunk_size = chunk_size/2
roughness = roughness/2
if chunk_size <= 1 then pause = true end
state = states.square
end

function love.update(dt)

if not pause then
buffer = buffer or 0
if buffer > 0.1 then
buffer = buffer - 0.1
else
buffer = buffer + dt
return
end
update[state]()
end
end

function get_power (value)
local n = -1
while value > 1 do
n=n+1
value = value/2
end
return n
end

function love.draw()

love.graphics.setColor(1,1,1)
love.graphics.print(chunk_size,0,0)
love.graphics.print(map_n,0,20)

local rez = height/(map_size+2)
--	print (rez .. ' '..get_power (rez))
rez = 2^get_power (rez)
if rez < 1 then rez = 1 end

for i = 1, map_size do
for j = 1, map_size do
local c = map[i] and map[i][j] or nil
if c then

if c > 1 then
c = 1
elseif c < 0 then
c = 0
end
love.graphics.setColor(get_color(c^2))

if rez > 1 then
love.graphics.rectangle("fill", rez*i, rez*j, rez, rez)
else
love.graphics.points(i, j)
end

if map_n < 5 then
if c < 0.75 then
love.graphics.setColor(1,1,1)
else
love.graphics.setColor(0,0,0)
end
love.graphics.print(math.floor(c*100), rez*i, rez*j)
end
end
end
end

end

function ser (tabl)
local str = string.char (10) .. "{"
for i, v in pairs (tabl) do
if type (v) == "table" then
str = str
str = str ..ser (v)
--			str = str .. string.char (10)
elseif type (v) == "number" then
str = str .. math.floor(v*255)
else
str = str .. v
end
str = str .. ','
end
return str .. "}"
end

function love.keypressed(key, scancode, isrepeat)
if key == "space" then
pause = not pause
elseif key then
map_n = map_n + 1
elseif key == "r" then
elseif key == "s" then
map_n = math.max(1, map_n - 1)
elseif key == "k" then
--		love.filesystem.write( "test.lua", "a")
--		love.filesystem.write( "test.lua", "b")
love.filesystem.write( "map-"..map_size..".lua", "return	" .. ser (map))
elseif key == "f11" then
fullscreen = not fullscreen
love.window.setFullscreen( fullscreen )

elseif key == "escape" then
love.event.quit()
end
end

Sorry for image brightness
Attachments
If you look close you can see the black dots
Screenshot_2021-07-31-22-44-29.png (45.79 KiB) Viewed 5747 times
Why can't pirates code in lua? Because they spend to much time at C!

-It might look like nonsense but there's so much proof.
-Some more if you pls... .
It has to be real then, all that talk about the end .
-How to be saved
Gunroar:Cannon()
Party member
Posts: 519
Joined: Thu Dec 10, 2020 1:57 am

### Re: Diamond Square Procedural Map Generation

darkfrei wrote: Tue Jun 22, 2021 8:12 pm
Gunroar:Cannon() wrote: Tue Jun 22, 2021 7:32 pm So it's like Perlin/Simplex noise. Can it go on forever or only a defined size can be generated when you want it(good either way).
.
You can add another square near the old one.
Smallest field is 3x3, the next one is 5x5, the next one is 17x17. Yeah, side = 2^N + 1.
Wait, will the map continue or will it be different?
Why can't pirates code in lua? Because they spend to much time at C!

-It might look like nonsense but there's so much proof.
-Some more if you pls... .
It has to be real then, all that talk about the end .
-How to be saved
darkfrei
Party member
Posts: 393
Joined: Sat Feb 08, 2020 11:09 pm

### Re: Diamond Square Procedural Map Generation

Gunroar:Cannon() wrote: Wed Aug 11, 2021 8:03 pm
darkfrei wrote: Tue Jun 22, 2021 8:12 pm
Gunroar:Cannon() wrote: Tue Jun 22, 2021 7:32 pm So it's like Perlin/Simplex noise. Can it go on forever or only a defined size can be generated when you want it(good either way).
.
You can add another square near the old one.
Smallest field is 3x3, the next one is 5x5, the next one is 17x17. Yeah, side = 2^N + 1.
Wait, will the map continue or will it be different?
You are need at least fourth base points, all another points are just interpolation of them.
But you can also make 6, 8 (for rectangles, not square) or another amount of base points.

The middle point of that base points can be also fixed, the interpolation is not necessary.
Falling in LÖVE
I Löve Lua and Love2D
pgimeno
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Posts: 2781
Joined: Sun Oct 18, 2015 2:58 pm

### Re: Diamond Square Procedural Map Generation

It's possible to make it seamless, but there are still artifacts at the seams. Perlin noise also suffers from something similar, incidentally, but not simplex noise from what I've read. I haven't seen a decent simplex noise generator to check.
Attachments
diamondSquareSeamless.love
Gunroar:Cannon()
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Posts: 519
Joined: Thu Dec 10, 2020 1:57 am

### Re: Diamond Square Procedural Map Generation

pgimeno wrote: Thu Aug 12, 2021 11:23 pm It's possible to make it seamless, but there are still artifacts at the seams. Perlin noise also suffers from something similar, incidentally, but not simplex noise from what I've read. I haven't seen a decent simplex noise generator to check.
Wow, nice pgimeno! You're really smart. But it seems to complicated for me to implement in my project. I generate different maps for different positions (corner)
1: x=0,y=map_size
2:x=map_size,y=map_size*2
...
It seems to work but sadly I can't get canvases split into chunks .
Why can't pirates code in lua? Because they spend to much time at C!

-It might look like nonsense but there's so much proof.
-Some more if you pls... .
It has to be real then, all that talk about the end .
-How to be saved

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