Class: Pongo::AngularConstraint

Inherits:
SpringConstraint show all
Defined in:
lib/pongo/angular_constraint.rb

Overview

An Angular Constraint between 3 particles

Instance Attribute Summary collapse

Attributes inherited from SpringConstraint

#collidable, #p1, #p2, #rest_length, #scp

Attributes inherited from AbstractConstraint

#stiffness

Attributes inherited from AbstractItem

#always_repaint, #display_object, #display_object_offset, #display_object_rotation, #fill_alpha, #fill_color, #line_alpha, #line_color, #line_thickness, #renderer, #solid, #user_data, #visible

Instance Method Summary collapse

Methods inherited from SpringConstraint

#angle, #center, #check_particles_location, #collidable?, #curr_length, #delta, #fixed_end_limit, #fixed_end_limit=, #init, #init_display, #radian, #rect_height, #rect_height=, #rect_scale, #rect_scale=, #set_collidable

Methods inherited from AbstractItem

#add_event_listener, #always_redraw!, #always_redraw=, #always_redraw?, #cleanup, #dispatch_event, #draw, #has_event_listener, #init, #set_fill, #set_line, #set_style, #visible!, #visible?

Constructor Details

#initialize(p1, p2, p3, min_ang, max_ang, options = {}) ⇒ AngularConstraint

Returns a new instance of AngularConstraint.



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# File 'lib/pongo/angular_constraint.rb', line 8

def initialize(p1, p2, p3, min_ang, max_ang, options={})
  options = {:min_break_ang => -10, :max_break_ang => 10, :stiffness => 0.5, 
    :dependent => false, :collidable => false, :rect_height => 1, :rect_scale => 1, 
    :scale_to_length => false}.update(options)

  super(p2, p2, stiffness, false, dependent, collidable, rect_height, rect_scale, scale_to_length)

  self.p3 = p3
  if min_ang == 10
    self.min_ang = ac_radian
    self.max_ang = ac_radian
  else
    self.min_ang = min_ang
    self.max_ang = max_ang
  end
  self.min_break_ang = min_break_ang
  self.max_break_ang = max_break_ang
end

Instance Attribute Details

#max_ang ⇒ Object

Returns the value of attribute max_ang.



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# File 'lib/pongo/angular_constraint.rb', line 6

def max_ang
  @max_ang
end

#max_break_ang ⇒ Object

Returns the value of attribute max_break_ang.



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# File 'lib/pongo/angular_constraint.rb', line 6

def max_break_ang
  @max_break_ang
end

#min_ang ⇒ Object

Returns the value of attribute min_ang.



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# File 'lib/pongo/angular_constraint.rb', line 6

def min_ang
  @min_ang
end

#min_break_ang ⇒ Object

Returns the value of attribute min_break_ang.



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# File 'lib/pongo/angular_constraint.rb', line 6

def min_break_ang
  @min_break_ang
end

#p3 ⇒ Object

Returns the value of attribute p3.



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# File 'lib/pongo/angular_constraint.rb', line 6

def p3
  @p3
end

Instance Method Details

#ac_radian ⇒ Object

The current difference between the angle of p1, p2, and p3 and a straight line (pi)



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# File 'lib/pongo/angular_constraint.rb', line 28

def ac_radian
  ang12 = Math.atan2(@p2.curr.y - @p1.curr.y, @p2.curr.x - @p1.curr.x)
  ang23 = Math.atan2(@p3.curr.y - @p2.curr.y, @p3.curr.x - @p2.curr.x)
  ang12 - ang23
end

#fixed? ⇒ Boolean Also known as: fixed

Returns true if any connected particle’s fixed property is true.

Returns:

  • (Boolean) 


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# File 'lib/pongo/angular_constraint.rb', line 41

def fixed?
  @p1.fixed? and @p2.fixed? and @p3.fixed?
end

#is_connected_to?(p) ⇒ Boolean

Returns true if the passed particle is one of the three particles attached to this AngularConstraint.

Returns:

  • (Boolean) 


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# File 'lib/pongo/angular_constraint.rb', line 36

def is_connected_to?(p)
  [@p1, @p2, @p3].include?(p)
end

#resolve ⇒ Object 



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# File 'lib/pongo/angular_constraint.rb', line 46

def resolve
  return if broken
  
  ang12 = Math.atan2(@p2.curr.y - @p1.curr.y, @p2.curr.x - @p1.curr.x)
  ang23 = Math.atan2(self.p3.curr.y - @p2.curr.y, self.p3.curr.x - @p2.curr.x)

  ang_diff = normalize_angle(ang12 - ang23)

  p2_inv_mass = dependent ? 0 : @p2.inv_mass

  sum_inv_mass = @p1.inv_mass + p2_inv_mass
  mult1 = @p1.inv_mass / sum_inv_mass
  mult2 = p2_inv_mass / sum_inv_mass
  ang_change = 0

  low_mid = (self.max_ang - self.min_ang) / 2
  high_mid = (self.max_ang + self.min_ang) / 2
  break_ang = (self.max_break_ang - self.min_break_ang) / 2

  new_diff = normalize_angle(high_mid - ang_diff)

  if new_diff > low_mid
    if new_diff > break_ang
      diff = new_diff - break_ang
      broken = true
      if has_event_listener(BreakEvent::ANGULAR)
        dispatch_event(BreakEvent.new(BreakEvent::ANGULAR, diff))
      end
      return
    end
    ang_change = new_diff - low_mid
  elsif new_diff < -low_mid
    if new_diff < -break_ang
      diff = new_dif + break_ang
      broken = true
      if has_event_listener(BreakEvent::ANGULAR)
        dispatch_event(BreakEvent.new(BreakEvent::ANGULAR, diff))
      end
      return
    end
    ang_change = new_diff + low_mid
  end

  final_ang = ang_change * self.stiffness + ang12
  displace_x = @p1.curr.x + (@p2.curr.x - @p1.curr.x) * mult1
  displace_y = @p1.curr.y + (@p2.curr.y - @p1.curr.y) * mult1

  @p1.curr.x = displace_x + Math.cos(final_ang + Math::PI) * rest_length * mult1
  @p1.curr.x = displace_y + Math.sin(final_ang + Math::PI) * rest_length * mult1
  @p2.curr.x = displace_x + Math.cos(final_ang) * rest_length * mult2
  @p2.curr.y = displace_y + Math.sin(final_ang) * rest_length * mult2
end