Grappling hook

hook.rb

def center_x
  @x / 2
end

def center_y
  @y / 2
end

def normalize(x, y)
  magn = Math.sqrt(x*x + y*y)
  [x / magn, y / magn]
end

swing_x = @x - @hook.x
swing_y = @y - @hook.y
norm = normalize(swing_x, swing_y)

# Step 1
@x = Math.cos(@hook_angular_velocity) * (self.center_x - @hook.center_x) - Math.sin(@hook_angular_velocity) * (self.center_y - @hook.center_y) + @hook.center_x
@y = Math.sin(@hook_angular_velocity) * (self.center_x - @hook.center_x) + Math.cos(@hook_angular_velocity) * (self.center_y - @hook.center_y) + @hook.center_y


# Step 2
# @x = Math.cos(@hook_angular_velocity + norm.first) * (@x - @hook.x) - Math.sin(@hook_angular_velocity + norm.first) * (@y - @hook.y) + @hook.x
# @y = Math.sin(@hook_angular_velocity + norm.first) * (@x - @hook.x) + Math.cos(@hook_angular_velocity + norm.first) * (@y - @hook.y) + @hook.y

# Step 3
# @x = Math.cos(@hook_angular_velocity * @friction + norm.first) * (@x - @hook.x) - Math.sin(@hook_angular_velocity * @friction + norm.first) * (@y - @hook.y) + @hook.x
# @y = Math.sin(@hook_angular_velocity * @friction + norm.first) * (@x - @hook.x) + Math.cos(@hook_angular_velocity * @friction + norm.first) * (@y - @hook.y) + @hook.y