#--
# *** This code is copyright 2004 by Gavin Kistner
# *** It is covered under the license viewable at http://phrogz.net/JS/_ReuseLicense.txt
# *** Reuse or modification is free provided you abide by the terms of that license.
# *** (Including the first two lines above in your source code usually satisfies the conditions.)
#++
# Author::     Gavin Kistner  (mailto:gavin@refinery.com)
# Copyright::  Copyright (c)2004 Gavin Kistner
# License::    See http://Phrogz.net/JS/_ReuseLicense.txt for details
# Version::    1.3, 2004-Oct-3
# Full Code::  link:../Geodesic_SketchUp.rb
#
# This file allows the user to add geodesic models to SketchUp (http://www.sketchup.com).
#
# See the Sketchup::Geodesic.create method for more information on creating and adding a geodesic dome/sphere.
#
# ====Version History
#  20040916  v1.0    Initial release; relies on Geodesic.rb
#  20040920  v1.1    Rewrite to use only SketchUp classes
#  20040920  v1.1.1  Fixed it to actually load ;)
#  20040920  v1.2.1  Added icosahedron option. Spruce up documentation.
#  20041003  v1.3    Added primitive picker to the dialog interface. (Thanks TBD!)

# The Sketchup::Geodesic class cannot be instantiated; it is a wrapper for the Sketchup::Geodesic.create method. See that method for more details.
class Sketchup::Geodesic
	SQRT2 = Math.sqrt(2)
	SQRT3 = Math.sqrt(3)
	
	TETRA_Q = SQRT2 / 3
	TETRA_R = 1.0 / 3
	TETRA_S = SQRT2 / SQRT3
	TETRA_T = 2 * SQRT2 / 3

	GOLDEN_MEAN = (Math.sqrt(5)+1)/2
	
	PRIMITIVES = {
		:tetrahedron => {
			:points => {
				:a => Geom::Vector3d.new( -TETRA_S, -TETRA_Q, -TETRA_R ),
				:b => Geom::Vector3d.new(  TETRA_S, -TETRA_Q, -TETRA_R ),
				:c => Geom::Vector3d.new(        0,  TETRA_T, -TETRA_R ),
				:d => Geom::Vector3d.new(        0,        0,        1 )
			},
			:faces => %w| acb abd adc dbc |
		},
		:octahedron => {
			:points => {
				:a => Geom::Vector3d.new(  0,  0,  1 ),
				:b => Geom::Vector3d.new(  1,  0,  0 ),
				:c => Geom::Vector3d.new(  0, -1,  0 ),
				:d => Geom::Vector3d.new( -1,  0,  0 ),
				:e => Geom::Vector3d.new(  0,  1,  0 ),
				:f => Geom::Vector3d.new(  0,  0, -1 )
			},
			:faces => %w| cba dca eda bea
			              def ebf bcf cdf |
		},
		:icosahedron => {
			:points => {
				:a => Geom::Vector3d.new(  1,  GOLDEN_MEAN, 0 ),
				:b => Geom::Vector3d.new(  1, -GOLDEN_MEAN, 0 ),
				:c => Geom::Vector3d.new( -1, -GOLDEN_MEAN, 0 ),
				:d => Geom::Vector3d.new( -1,  GOLDEN_MEAN, 0 ),
				:e => Geom::Vector3d.new(  GOLDEN_MEAN, 0,  1 ),
				:f => Geom::Vector3d.new( -GOLDEN_MEAN, 0,  1 ),
				:g => Geom::Vector3d.new( -GOLDEN_MEAN, 0, -1 ),
				:h => Geom::Vector3d.new(  GOLDEN_MEAN, 0, -1 ),
				:i => Geom::Vector3d.new( 0,  1,  GOLDEN_MEAN ),
				:j => Geom::Vector3d.new( 0,  1, -GOLDEN_MEAN ),
				:k => Geom::Vector3d.new( 0, -1, -GOLDEN_MEAN ),
				:l => Geom::Vector3d.new( 0, -1,  GOLDEN_MEAN ),

			},
			:faces => %w| iea iad idf ifl ile
			              eha ajd dgf fcl lbe
			              ebh ahj djg fgc lcb
			              khb kjh kgj kcg kbc |
		}
	}
	
	PRIMITIVES.each_pair{ |primitive, pf|
		PRIMITIVES[primitive] = pf[:faces].collect{ |pts|
			pts.split('').collect{ |pt_name|
				pf[:points][pt_name.to_sym]
			}
		}
	}

	# Adds a new geodesic dome/sphere to SketchUp inside a group.
	#
	# _frequency_::  The number of times to subdivide each face of the primitive; a frequency of <tt>0</tt> yields the primitive itself.
	# _primitive_::  The type of primitive to use as a basis for the geodesic. May be one of <tt>:tetrahedron</tt>, <tt>:octahedron</tt>, or <tt>:icosahedron</tt>. Defaults to <tt>:octahedron</tt>.
	# _radius_::     An initial radius for the geodesic, in inches. Defaults to <tt>11</tt>.
    #
    # If +frequency+ is not supplied, a prompt will be shown to the user, asking for the value of the +frequency+ and +radius+ parameters.
	# The number of faces in the geodesic is <tt>(faces in primitive) * 4^frequency</tt>. Note how quickly the number of faces grows:
	# 
	#   frequency  tetrahedron  octahedron  icosahedron
	#       0           4           8            20
	#       1          16          32            80
	#       2          64         128           320
	#       3         256         512          1280
	#       4        1024        2048          5120
	#       5        4096        8192         20480
	#       6       16384       32678         81920
	#
    # For this reason, you should take care not to specify an overly-large +frequency+ value. The following graphic gives a visual depiction of the frequency value:
	#
    # link:../Geodesics.png.
    #
	# A +frequency+ of 3 for an octahedron passes pretty well as a sphere (512 faces) and even a value of 2 for an icosahedron (320 faces).
    #
    # Returns the new Sketchup::Group instance holding the geodesic.
    #
    # Examples:
    #   Sketchup::Geodesic.create( 2 )                # Add an octahedron-based geodesic with radius of 36" and frequency 2
    #   Sketchup::Geodesic.create( 0, :tetrahedron )  # Add a tetrahedron of radius 36"
    #   Sketchup::Geodesic.create                     # Prompts the user for primitive, radius and frequency
	def self.create( frequency = nil, primitive = :octahedron, radius = 36 )
		if !frequency
			prompts = [ 'Primitive:', 'Radius (in "):', 'Subdivisions:' ]
			values = [ primitive.to_s, radius, 2 ]
			primitive_types = ['tetrahedron|octahedron|icosahedron']
			results = inputbox prompts, values, primitive_types, 'Create Geodesic'
			return unless results
			primitive, radius, frequency = results
			primitive = primitive.to_sym
		end

		raise "The Geodesic class does not support the primitive type '#{primitive}'" unless PRIMITIVES[primitive]

		model = Sketchup.active_model
		model.start_operation "Create Geodesic"
		group = model.active_entities.add_group

		PRIMITIVES[primitive].each{ |face|
			self.expand_face( face, frequency.to_i, radius.to_f, group.entities )
		}

	    model.commit_operation
	    group
	end

	# Used by the Sketchup::Geodesic.create method; takes a 'face' (array of 3 Vector3d points),
	# and recursively subdivides it the number of times specified by +frequency+; if +frequency+
	# is 0, pushes the points out to a specific +radius+ and then adds the face to +entities+.
	def self.expand_face( face, frequency, radius, entities )
		if frequency < 1
			entities.add_face(
				face.collect{ |v|
					v.normalize.scale_by( radius ).to_point3d
				}
			)
		else
			a,b,c = face
			ab = a + (b-a).scale_by( 0.5 ) 
			ac = a + (c-a).scale_by( 0.5 )
			bc = b + (c-b).scale_by( 0.5 )
			[
				[ a,  ab, ac ],
				[ b,  bc, ab ],
				[ c,  ac, bc ],
				[ ab, bc, ac ]
			].each{ |f|
				self.expand_face( f, frequency-1, radius, entities )
			}
		end
	end

end


# Wrapper module for the #smooth_all and #unsmooth_all methods.
module Smoothable
	# Sets the <tt>smooth</tt> property of every edge in the group/model to the value of <tt>new_smooth</tt>; if <tt>new_smooth</tt> is not supplied, defaults to +true+.
	def smooth_all( new_smooth = true )
		model = Sketchup.active_model
		model.start_operation "#{new_smooth ? 'Smooth' : 'Unsmooth'} All"
		self.entities.each{ |e|
			next unless e.is_a?( Sketchup::Edge )
			e.smooth = new_smooth;
		}
	    model.commit_operation
	end

	# Sets the <tt>smooth</tt> property of every edge in the group/model to false.
	def unsmooth_all
		self.smooth_all( false )
	end
end

# Extending the SketchUp Group class to support a new Smoothable#smooth_all method.
class Sketchup::Group
	include Smoothable
	
	# Convenience method to move the group to a specified location, since I couldn't figure out anything simpler than:
	#
	#   my_group.move!( Geom::Transformation.translation(Geom::Vector3d.new( x, y, z ) ) )
	def move_to( x, y, z )
		self.move!( Geom::Transformation.translation(Geom::Vector3d.new( x, y, z ) ) )
	end
end

# Extending the SketchUp Model class to support a new Smoothable#smooth_all method.
class Sketchup::Model; include Smoothable; end

# Extensions to the Geom::Vector class in SketchUp
class Geom::Vector3d

	# Modifies the receiving Vector3d, multiplying each x/y/z component by the argument.
	def scale_by( n )
		self.x *= n
		self.y *= n
		self.z *= n
		self
	end

	def to_point3d
		Geom::Point3d.new( *self.to_a )
	end
end

UI.menu("Plugins").add_item("Create Geodesic") {
	Sketchup::Geodesic.create
}