2024-06-11 21:37:04 +00:00
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& Example Ludus implementation of the Sierpinski triangle.
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& https://en.m.wikipedia.org/wiki/L-system#Example_5:_Sierpinski_triangle
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& The Sierpinski triangle drawn using an L-system
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& variables : F G
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2024-06-14 17:52:54 +00:00
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& constants : + -
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& start : F-G-G
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& rules : (F -> F-G+F+G-F), (G -> GG)
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2024-06-11 21:37:04 +00:00
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& angle : 120°
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2024-06-14 17:52:54 +00:00
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& F and G both mean "draw forward", + means "turn left by angle", and − means "turn right by angle".
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2024-06-11 21:37:04 +00:00
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& set a length for each segment
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let length = 10
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& set an angle for all turns, default to 1/3 for triangles
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let angle = inv(1)
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& define 'G' function from the grammaer
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fn g! {
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(0) -> fd!(length)
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(n) -> {
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g!(dec(n))
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g!(dec(n))
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}
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}
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& define 'F' function from the grammaer
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fn f! {
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(0) -> fd!(length)
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(n) -> {
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f!(dec(n))
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rt!(angle)
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g!(dec(n))
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lt!(angle)
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f!(dec(n))
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lt!(angle)
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g!(dec(n))
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rt!(angle)
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f!(dec(n))
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}
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}
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& this function defines the starting pattern.
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& each of the f! and g! calls expand based on the grammar at the top of this example
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fn sierp! (times) -> {
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f!(times)
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rt!(angle)
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g!(times)
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rt!(angle)
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g!(times)
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}
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& call the base function with a number of iterations
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& remember, this is exponential! high numbers can freeze your browser.
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sierp!(7)
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