Koch curve: Difference between revisions
Forth (4tH) version added
(Ada version) |
(Forth (4tH) version added) |
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[https://i.imgur.com/MVS8QiS.png]
=={{header|Forth}}==
{{works with|4tH v3.64}}
<lang>include lib/graphics.4th
include lib/math.4th
include lib/enter.4th
: (p3&p5) 2* + 3 / ; ( n1 n2 -- n2+n2+n1/3)
: (p3) rot (p3&p5) >r swap (p3&p5) r> ;
: (p5) rot swap (p3&p5) >r (p3&p5) r> ;
: (*/10K) * 10K 2 / + 10K / ; ( n1 n2 -- n1*n2/10000)
: koch ( x1 y1 x2 y2 n --)
dup 0> if
1- >r 2over 2over (p5)
2>r 2over 2over (p3) 2r> ( x1 y1 x2 y2 x3 y3 x5 y5 )
PI*10K 3 / >r 2over 2over rot - >r swap - >r ( R: n theta y5-y3 x5-x3)
2over r@ r"@ (sin) (*/10K) - r'@ r"@ (cos) (*/10K) +
swap r@ r"@ (cos) (*/10K) + r'@ r"@ (sin) (*/10K) +
rdrop rdrop rdrop swap ( x1 y1 x2 y2 x3 y3 x5 y5 x4 y4 R: n)
2rot 2>r 2>r 2rot 2r> 2r> 2rot ( x2 y2 x5 y5 x4 y4 x3 y3 x1 y1 R: n)
2over r@ recurse ( x2 y2 x5 y5 x4 y4 x3 y3 R: n )
2over r@ recurse ( x2 y2 x5 y5 x4 y4 R: n )
2over r@ recurse ( x2 y2 x5 y5 R: n)
2swap r> recurse ( --)
;then drop line
;
600 pic_width ! 600 pic_height ! \ set canvas size
color_image 255 whiteout blue \ paint blue on white
." Level (0-4): " enter 0 max 4 min >r
450 100 450 500 r@ koch \ paint the snowflake
115 300 450 100 r@ koch
450 500 115 300 r> koch
s" gkoch.ppm" save_image \ save the image</lang>
=={{header|FreeBASIC}}==
<lang freebasic>
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