Sha256: c5c82bcec0b6cf23e4dfa9eb5237fce1125e60ec0001b270382fb7795900babf
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Size: 1.73 KB
Versions: 7
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Stored size: 1.73 KB
Contents
class Icosahedron
include Processing::Proxy # mixin Processing::Proxy
attr_reader :r
def initialize(radius)
@r = radius
end
##
# Draw an icosahedron defined by a radius r.
#
def draw
# Calculate the vertex data for an icosahedron inscribed by a sphere radius 'r'.
# Use 4 Golden Ratio rectangles as the basis.
phi = (1.0 + Math.sqrt(5.0)) / 2.0
h = r / Math.sqrt(1.0 + phi * phi)
v =
[
Vec3D.new(0, -h, h * phi), Vec3D.new(0, -h, -h * phi), Vec3D.new(0, h, -h * phi), Vec3D.new(0, h, h * phi),
Vec3D.new(h, -h * phi, 0), Vec3D.new(h, h * phi, 0), Vec3D.new(-h, h * phi, 0), Vec3D.new(-h, -h * phi, 0),
Vec3D.new(-h * phi, 0, h), Vec3D.new(-h * phi, 0, -h), Vec3D.new(h * phi, 0, -h), Vec3D.new(h * phi, 0, h)
]
begin_shape(TRIANGLES)
draw_triangle(v[0], v[7],v[4])
draw_triangle(v[0], v[4], v[11])
draw_triangle(v[0], v[11], v[3])
draw_triangle(v[0], v[3], v[8])
draw_triangle(v[0], v[8], v[7])
draw_triangle(v[1], v[4], v[7])
draw_triangle(v[1], v[10], v[4])
draw_triangle(v[10], v[11], v[4])
draw_triangle(v[11], v[5], v[10])
draw_triangle(v[5], v[3], v[11])
draw_triangle(v[3], v[6], v[5])
draw_triangle(v[6], v[8], v[3])
draw_triangle(v[8], v[9], v[6])
draw_triangle(v[9], v[7], v[8])
draw_triangle(v[7], v[1], v[9])
draw_triangle(v[2], v[1], v[9])
draw_triangle(v[2], v[10], v[1])
draw_triangle(v[2], v[5], v[10])
draw_triangle(v[2], v[6], v[5])
draw_triangle(v[2], v[9], v[6])
end_shape
end
def draw_triangle(p1, p2, p3)
vertex(p1.x, p1.y, p1.z)
vertex(p2.x, p2.y, p2.z)
vertex(p3.x, p3.y, p3.z)
end
end
Version data entries
7 entries across 7 versions & 1 rubygems