L Systems - plant

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Pakz	Created : 28 October 2021 Edited : 28 October 2021 Language : Lua - codea(ios) L Systems - plant L systems - string with turtle instructions
-- L Systems str = "F" -- Use this function to perform your initial setup function setup() print("Hello World!") for i=1,4 do newstr = "" for j=1,string.len(str) do -- if F then insert new string if string.sub(str,j,j) == "F" then newstr = newstr .. "FF+[+F-F-F]-[-F+F+F]" else -- add to string newstr = newstr..string.sub(str,j,j) end end -- copy new string into str str = newstr end end -- This function gets called once every frame function draw() -- This sets a dark background color background(40, 40, 50) -- This sets the line thickness strokeWidth(1) -- set to center of screen -- opengl system translate(WIDTH/2,HEIGHT/2) -- move up rotate(90) makedrawing(str,111) -- Do your drawing here end function makedrawing(str,seed) math.randomseed(seed) len = 5 for i = 1,string.len(str) do a = string.sub(str,i,i) -- draw line and move if a == "F" then len = math.random(1,7) line(0,0,len,0) translate(len,0) end -- not used if a == "G" then translate(len,0) end -- rotate left if a == "-" then rotate(-25) end -- rotate right if a == "+" then rotate(25) end -- store location if a == "[" then pushMatrix() end -- restore to previous location if a == "]" then popMatrix() end end end --v
Latest Update This from the Nature of Code book(free online) It is a system to draw things from a string that contains turtle instructions. You start with a string with say the character "F" By continiously replacing this character F with new set of characters you build a string that draws a plant like drawing. Look at the code at the instructions that are in this example. The pop and push matrix are used to store the current drawing location and to restore to the previous drawing location. I think this code actually tought me how these things like translate and rotate and popmatrix work. I wil add a screenshot soon. On iphone right now.

Comments
Thursday, 28 October 2021, 08:16
rockford	Looks pretty good
Thursday, 28 October 2021, 08:31
Jayenkai	It's a lovely generator!
Thursday, 28 October 2021, 08:35
Pakz	On the nature of code book site there are links to more of those build string formula's. This L Systems were invented in the 70s or so and thus have a lot of documentation. It is in the fractals chapter.

L Systems - plant

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