nicklink483/dare

require 'opal' #this will be removed when 0.7.0 is released
require 'opal-jquery'
require_tree 'dare'

module Dare

  # returns the current version of this gem
  VERSION = "0.2.0"

  # returns the magnitude of the horizontal component of a vector
  # at some angle and some magnitude where the angle is in degrees
  # starting on the unit circle pointing to the right and going
  # counterclockwise
  # e.g.
  # Dare.offset_x(90, 10) # returns 0
  # Dare.offset_x(45, 10) # returns 10 times the square root of 2
  #
  def self.offset_x(angle, magnitude)
    `#{magnitude}*Math.cos(-#{angle}*Math.PI/180.0)`
  end

  # returns the magnitude of the vertical component of a vector
  # at some angle and some magnitude where the angle is in degrees
  # starting on the unit circle pointing to the right and going
  # counterclockwise
  # e.g.
  # Dare.offset_y(90, 10) # returns 10
  # Dare.offset_y(45, 10) # returns 10 times the square root of 2
  #
  def self.offset_y(angle, magnitude)
    `#{magnitude}*Math.sin(-#{angle}*Math.PI/180.0)`
  end

  # returns the number of milliseconds since the Unix epoch
  # useful for delta physics
  #
  def self.ms
    `(new Date()).getTime()`
  end

  def self.distance(x1, y1, x2, y2)
    `Math.sqrt((x2-x1)*(x2-x1) + (y2-y1)*(y2-y1))`
  end

  class << self
    attr_accessor :default_canvas
  end
end