class Mittsu::CircleGeometry

Public Class Methods

new(radius = 50.0, segments = 8, theta_start = 0.0, theta_length = (::Math::PI * 2.0)) click to toggle source
Calls superclass method Mittsu::Geometry::new
# File lib/mittsu/extras/geometries/circle_geometry.rb, line 6
def initialize(radius = 50.0, segments = 8, theta_start = 0.0, theta_length = (::Math::PI * 2.0))
  super()

  @type = 'CircleGeometry'

  @parameters = {
    radius:       radius,
    segments:     segments,
    theta_start:  theta_start,
    theta_length: theta_length
  }

  segments = [3, segments].max

  center = Vector3.new
  center_uv = Vector2.new(0.5, 0.5)

  @vertices << center
  uvs = [center_uv]

  for i in 0..segments do
    vertex = Vector3.new
    segment = theta_start + i.to_f / segments.to_f * theta_length

    vertex.x = radius * ::Math.cos(segment)
    vertex.y = radius * ::Math.sin(segment)

    @vertices << vertex
    uvs << Vector2.new((vertex.x / radius + 1.0) / 2.0, (vertex.y / radius + 1.0) / 2.0)
  end

  n = Vector3.new

  for i in 1..segments do
    @faces << Face3.new(i, i + 1, 0, [n.clone, n.clone, n.clone])
    @face_vertex_uvs[0] << [uvs[i].clone, uvs[i + 1].clone, center_uv.clone]
  end

  compute_face_normals
  @bounding_sphere = Sphere.new(Vector3.new, radius)
end