dyanamic color table

Author: monkstone

contributed/spiky_orb.rb

@@ -0,0 +1,171 @@
+# spiky_orb.rb
+# After a vanilla processing sketch by
+# Ben Notorianni aka lazydog
+# Features dynamic creation of a colour table
+BALL_RADIUS = 160
+
+attr_reader :colour_table, :orb_vertices, :flat, :smoothing, :sub_division_depth
+attr_reader :orb_radii
+
+def settings
+  size 640, 480, P3D
+end
+
+def setup
+  sketch_title 'Spiky Orb'
+  @orb_vertices = []
+  @flat = false
+  @smoothing = 3
+  @sub_division_depth = 4
+end
+
+def draw
+  background(0)
+  lights
+  spot_light(255, 255, 255, 400, 400, 400, -1, -1, -1, PI / 2, 2)
+  translate(width / 2, height / 2)
+  smooth_rotation(5.0, 6.7, 7.3)
+  create_sphere
+  draw_tesselated_icosahedron(orb_vertices, colour_table)
+end
+
+def calc_color(red, green, blue)
+  r = 127 * sin(PI * frame_count * red) + 127
+  g = 127 * sin(PI * frame_count * green) + 127
+  b = 127 * sin(PI * frame_count * blue) + 127
+  color(r, g, b)
+end
+
+def generate_colour_table(depth)
+  c1 = calc_color(0.00400, 0.002200, 0.00300)
+  c2 = calc_color(0.00328, 0.00328, 0.00328)
+  c3 = calc_color(0.00496, 0.00780, 0.00450)
+  c4 = calc_color(0.00420, 0.00520, 0.00620)
+  colour_set = [
+    [c1, c1, c1, c2],
+    [c1, c1, c1, c2],
+    [c1, c1, c1, c2],
+    [c4, c4, c4, c3]
+  ]
+  @colour_table = []
+  20.times do
+    (4**(depth - 1)).times do |j|
+      colour_table << colour_set[(j / 16) % 4][j % 4]
+    end
+  end
+  colour_table
+end
+
+def subdivide_triangle(depth, index, pt1, pt2, pt3)
+  if depth == 1
+    orb_vertices[index += 1] = pt1.x
+    orb_vertices[index += 1] = pt1.y
+    orb_vertices[index += 1] = pt1.z
+    orb_vertices[index += 1] = pt2.x
+    orb_vertices[index += 1] = pt2.y
+    orb_vertices[index += 1] = pt2.z
+    orb_vertices[index += 1] = pt3.x
+    orb_vertices[index += 1] = pt3.y
+    orb_vertices[index += 1] = pt3.z
+  else
+    vec1 = pt1 + pt2
+    vec2 = pt2 + pt3
+    vec3 = pt3 + pt1
+    if depth <= sub_division_depth - smoothing
+      vec1 *= 0.5
+      vec2 *= 0.5
+      vec3 *= 0.5
+    else
+      r = orb_radii[depth]
+      vec1 = vec1.normalize * r
+      vec2 = vec2.normalize * r
+      vec3 = vec3.normalize * r
+    end
+    index = subdivide_triangle(depth - 1, index, pt1, vec1, vec3)
+    index = subdivide_triangle(depth - 1, index, vec1, pt2, vec2)
+    index = subdivide_triangle(depth - 1, index, vec2, pt3, vec3)
+    index = subdivide_triangle(depth - 1, index, vec1, vec2, vec3)
+  end
+  index
+end
+
+def tesselate_icosahedron(radii, depth)
+  gr = (1 + sqrt(5)) / 2.0
+  r = radii[depth] / sqrt(1 + gr * gr)
+  v = [
+    Vec3D.new(0, -r, r * gr),
+    Vec3D.new(0, -r, -r * gr),
+    Vec3D.new(0,  r, -r * gr),
+    Vec3D.new(0, r, r * gr),
+    Vec3D.new(r, -r * gr, 0),
+    Vec3D.new(r, r * gr, 0),
+    Vec3D.new(-r, r * gr, 0),
+    Vec3D.new(-r, -r * gr, 0),
+    Vec3D.new(-r * gr, 0, r),
+    Vec3D.new(-r * gr, 0, -r),
+    Vec3D.new(r * gr, 0, -r),
+    Vec3D.new(r * gr, 0, r)
+  ]
+  index = 0
+  index = subdivide_triangle(depth, index, v[0], v[7], v[4])
+  index = subdivide_triangle(depth, index, v[0], v[4], v[11])
+  index = subdivide_triangle(depth, index, v[0], v[11], v[3])
+  index = subdivide_triangle(depth, index, v[0], v[3], v[8])
+  index = subdivide_triangle(depth, index, v[0], v[8], v[7])
+  index = subdivide_triangle(depth, index, v[1], v[4], v[7])
+  index = subdivide_triangle(depth, index, v[1], v[10], v[4])
+  index = subdivide_triangle(depth, index, v[10], v[11], v[4])
+  index = subdivide_triangle(depth, index, v[11], v[5], v[10])
+  index = subdivide_triangle(depth, index, v[5], v[3], v[11])
+  index = subdivide_triangle(depth, index, v[3], v[6], v[5])
+  index = subdivide_triangle(depth, index, v[6], v[8], v[3])
+  index = subdivide_triangle(depth, index, v[8], v[9], v[6])
+  index = subdivide_triangle(depth, index, v[9], v[7], v[8])
+  index = subdivide_triangle(depth, index, v[7], v[1], v[9])
+  index = subdivide_triangle(depth, index, v[2], v[1], v[9])
+  index = subdivide_triangle(depth, index, v[2], v[10], v[1])
+  index = subdivide_triangle(depth, index, v[2], v[5], v[10])
+  index = subdivide_triangle(depth, index, v[2], v[6], v[5])
+  subdivide_triangle(depth, index, v[2], v[9], v[6])
+end
+
+def smooth_rotation(ro1, ro2, ro3)
+  mills = millis * 0.00003
+  rotate_x 0.5 * Math.sin(mills * ro1) + 0.5
+  rotate_y 0.5 * Math.sin(mills * ro2) + 0.5
+  rotate_z 0.5 * Math.sin(mills * ro3) + 0.5
+end
+
+def generate_radii(base_radius, depth)
+  return (0..depth).map { base_radius } if flat
+
+  (0..depth).map do |i|
+    r = 2 * noise(frame_count * 0.003, (i.to_f / depth) - 1.0)
+    base_radius * (0.9 * r)
+  end
+end
+
+def draw_tesselated_icosahedron(verticies, colour_table)
+  index = 0
+  no_stroke
+  begin_shape(TRIANGLES)
+  colour_table.each do |col|
+    fill(col)
+    vertex(verticies[index += 1], verticies[index += 1], verticies[index += 1])
+    vertex(verticies[index += 1], verticies[index += 1], verticies[index += 1])
+    vertex(verticies[index += 1], verticies[index += 1], verticies[index += 1])
+  end
+  end_shape
+end
+
+def create_sphere
+  @orb_radii = generate_radii(BALL_RADIUS, sub_division_depth)
+  tesselate_icosahedron(orb_radii, sub_division_depth)
+  generate_colour_table(sub_division_depth)
+end
+
+def key_pressed
+  return unless key == 's'
+
+  @flat = !flat
+end