Class: Gosling::Polygon

Inherits:
Actor show all
Defined in:
lib/gosling/polygon.rb

Overview

A Polygon is an Actor with a shape defined by three or more vertices. Can be used to make triangles, hexagons, or any other unusual geometry not covered by the other Actors. For circles, you should use Circle. For squares or rectangles, see Rect.

Direct Known Subclasses

Rect

Instance Attribute Summary

Attributes inherited from Actor

#are_children_tangible, #are_children_visible, #children, #color, #is_mask, #is_tangible, #is_visible, #parent, #window

Attributes included from Transformable

#rotation

Instance Method Summary collapse

Methods inherited from Actor

#add_child, #alpha, #alpha=, #blue, #blue=, #draw, #get_actor_at, #get_actors_at, #get_global_position, #get_global_transform, #green, #green=, #has_child?, #inspect, #red, #red=, #remove_child

Methods included from Transformable

#center, #center=, #center_x, #center_x=, #center_y, #center_y=, #reset, #scale, #scale=, #scale_x, #scale_x=, #scale_y, #scale_y=, #to_matrix, transform_point, #transform_point, #translation, #translation=, untransform_point, #untransform_point, #x, #x=, #y, #y=

Constructor Details

#initialize(window) ⇒ Polygon

Creates a new, square Polygon with a width and height of 1.



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# File 'lib/gosling/polygon.rb', line 15

def initialize(window)
  type_check(window, Gosu::Window)
  super(window)
  @vertices = [
    Snow::Vec3[0, 0, 0],
    Snow::Vec3[1, 0, 0],
    Snow::Vec3[1, 1, 0],
    Snow::Vec3[0, 1, 0]
  ]
end

Instance Method Details

#get_global_vertices(out = nil) ⇒ Object

Returns an array containing all of our local vertices transformed to global-space. (See Actor#get_global_transform.)



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# File 'lib/gosling/polygon.rb', line 82

def get_global_vertices(out = nil)
  type_check(out, Array) unless out.nil?

  tf = MatrixCache.instance.get
  get_global_transform(tf)

  if out.nil?
    return @vertices.map { |v| Transformable.transform_point(tf, v, Snow::Vec3.new) }
  end

  @vertices.each_index do |i|
    v = @vertices[i]
    if out[i]
      Transformable.transform_point(tf, v, out[i])
    else
      out[i] = Transformable.transform_point(tf, v)
    end
  end
  out
ensure
  MatrixCache.instance.recycle(tf) if tf
end

#get_vertices ⇒ Object

Returns a copy of this Polygon’s vertices (@vertices is read-only).



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# File 'lib/gosling/polygon.rb', line 29

def get_vertices
  @vertices.dup
end

#is_point_in_bounds(point) ⇒ Object

Returns true if the point is inside of this Polygon, false otherwise.



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# File 'lib/gosling/polygon.rb', line 108

def is_point_in_bounds(point)
  Collision.is_point_in_shape?(point, self)
end

#set_vertices(vertices) ⇒ Object

Sets this polygon’s vertices. Requires three or more Snow::Vec2, Vec3, Vec4, or Arrays containing 2 or more numbers.

Usage:

  • polygon.set_vertices([Snow::Vec3[-1, 0, 0], Snow::Vec3[0, -1, 0], Snow::Vec3[1, 1, 0]])

Raises:

  • (ArgumentError) 


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# File 'lib/gosling/polygon.rb', line 40

def set_vertices(vertices)
  type_check(vertices, Array)
  raise ArgumentError.new("set_vertices() expects an array of at least three 2D vectors") unless vertices.length >= 3
  vertices.each do |v|
    types_check(v, Snow::Vec2, Snow::Vec3, Snow::Vec4, Array)
    if v.is_a?(Array)
      raise ArgumentError.new("set_vertices() expects an array of at least three 2D vectors") unless v.length >= 2
      v.each { |n| type_check(n, Numeric) }
    end
  end

  if @vertices.length < vertices.length
    @vertices.concat(Array.new(vertices.length - @vertices.length) { Snow::Vec3.new })
  elsif @vertices.length > vertices.length
    @vertices.pop(@vertices.length - vertices.length)
  end

  vertices.each_index { |i| @vertices[i].set(vertices[i][0], vertices[i][1], 0) }
end

#set_vertices_rect(width, height) ⇒ Object

Sets this polygon to a rectangular shape with the given width and height, with its upper left at local [0, 0].

Raises:

  • (ArgumentError) 


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# File 'lib/gosling/polygon.rb', line 63

def set_vertices_rect(width, height)
  raise ArgumentError.new("Expected positive non-zero integer, but received #{width.inspect}!") unless width > 0
  raise ArgumentError.new("Expected positive non-zero integer, but received #{height.inspect}!") unless height > 0

  if @vertices.length < 4
    @vertices.concat(Array.new(4 - @vertices.length) { Snow::Vec3.new })
  elsif @vertices.length > 4
    @vertices.pop(@vertices.length - 4)
  end

  @vertices[0].set(    0,      0, 0)
  @vertices[1].set(width,      0, 0)
  @vertices[2].set(width, height, 0)
  @vertices[3].set(    0, height, 0)
end