ioquatix/geospatial

# Copyright, 2015, by Samuel G. D. Williams. <http://www.codeotaku.com>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

require 'matrix'

module Geospatial
    class Box
        class << self
            def from_bounds(min, max)
                self.new(min, max-min, max)
            end
            
            alias [] from_bounds
            
            def enclosing_points(points)
                return nil unless points.any?
                
                min = points.first.to_a
                max = points.first.to_a
                
                points.each do |point|
                    point.each_with_index do |value, index|
                        if value < min[index]
                            min[index] = value
                        elsif value > max[index]
                            max[index] = value
                        end
                    end
                end
                
                return self.from_bounds(Vector.elements(min), Vector.elements(max))
            end
        end
        
        def initialize(origin, size, max = nil)
            @origin = origin
            @size = size
            @max = max
        end
        
        def freeze
            self.max
            
            super
        end
        
        attr :origin
        attr :size
        
        def to_s
            "#{self.class}[#{min.inspect}, #{max.inspect}]"
        end
        
        def min
            @origin
        end
        
        def max
            @max ||= @origin + @size
        end
        
        # This yields the four corners of the box.
        def corners
            return to_enum(:corners) unless block_given?
            
            yield(@origin)
            
            max = self.max
            yield(Vector[max[0], @origin[1]])
            yield(max)
            yield(Vector[@origin[0], max[1]])
        end
        
        def center
            @origin + (@size/2)
        end
        
        # This yields the midpoints of the four sides of the box.
        def midpoints
            return to_enum(:midpoints) unless block_given?
            
            size = self.size
            
            yield(Vector[@origin[0] + size[0] / 2, @origin[1]])
            yield(Vector[@origin[0] + size[0], @origin[1] + size[1] / 2])
            yield(Vector[@origin[0] + size[0] / 2, @origin[1] + size[1]])
            yield(Vector[@origin[0], @origin[1] + size[1] / 2])
        end
        
        def include_point?(point)
            2.times do |i|
                return false if point[i] < min[i] or point[i] >= max[i]
            end
            
            return true
        end
        
        def include?(other)
            include_point?(other.min) && include_point?(other.max)
        end
        
        def intersect?(other)
            2.times do |i|
                # Separating axis theorm, if the minimum of the other is past the maximum of self, or the maximum of other is less than the minimum of self, an intersection cannot occur.
                if other.min[i] > self.max[i] or other.max[i] < self.min[i]
                    return false
                end
            end
            
            return true
        end
    end
end