cfdg-examples/Polygon.cfdg at master · hirota1ro/cfdg-examples · GitHub

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startshape poly [ alpha -0.45 ]

RATIO = 1.8

shape poly
rule {
  polygon(3) []
  S = RATIO / 3
  poly [ x cos(0) y sin(0) size S ]
  poly [ x cos(120) y sin(120) size S ]
  poly [ x cos(240) y sin(240) size S ]
}
rule {
  polygon(4) []
  S = RATIO / 4
  poly [ x cos(0) y sin(0) size S ]
  poly [ x cos(90) y sin(90) size S ]
  poly [ x cos(180) y sin(180) size S ]
  poly [ x cos(270) y sin(270) size S ]
}
rule {
  polygon(5) []
  S = RATIO / 5
  poly [ x cos(0) y sin(0) size S ]
  poly [ x cos(72) y sin(72) size S ]
  poly [ x cos(144) y sin(144) size S ]
  poly [ x cos(216) y sin(216) size S ]
  poly [ x cos(288) y sin(288) size S ]
}

// 半径1の円に内接する正n角形を描く
path polygon(natural n) {
  θ = 360 / n
  loop i = n [] {
    if (i == 0) {
      MOVETO(cos(i * θ), sin(i * θ))
    } else {
      LINETO(cos(i * θ), sin(i * θ))
    }
  }
  CLOSEPOLY()
  STROKE()[]
}