rain2.rb

# Rain1 by Thomas R. "TomK32" Koll
#
# draws raindrops as bezier shapes and moves them downwards
# 
# available key commands:
#  + make raindrops heavier/bigger
#  - make raindrops smaller
#  a more raindrops
#  s less raindrops
#  <SPACE>
#
# License: Same as processing
#

def setup
	size 640, 480
	frame_rate 30
	@rain_drops = []
	@rain_drops.extend Runnable
	@rain_drops_size = 20
	@rain_drops_weight = 20
	@paused = false
	text_font(create_font("Univers66.vlw", 15), 15)
end

def draw
	return if @paused
	# we fill up with new drops randomly
	fill_up while rand(@rain_drops_size/3) < (@rain_drops_size - @rain_drops.size)
	
	drop_rate = @rain_drops.size/@rain_drops_size.to_f
	# the less drops the darker it is
	background (127+127*(@rain_drops.size/@rain_drops_size.to_f))

	@rain_drops.run
	text("#{@rain_drops.size} of #{@rain_drops_size} drops with a size of #{@rain_drops_weight}", 10, 20)
end

def fill_up
	@rain_drops << RainDrop.new(rand(width), rand(-height/2 .. 0), @rain_drops_weight) if @rain_drops.size < @rain_drops_size
end

def key_pressed
	case key
		when "+"
			@rain_drops_weight += 5
		when "-"
			@rain_drops_weight -= 5 if @rain_drops_weight > 10
		when "a"
			@rain_drops_size += 5
		when "s"
			@rain_drops_size -= 5 if @rain_drops_size > 5
		when " "
			@paused = !@paused
	end
end

module Runnable
	def run
		self.reject! { |item| item.dead? }
		self.each { |item| item.run }
	end
end

class RainDrop
	include Processing::Proxy
	def initialize(x, y, weight = nil)
		@weight = weight || 10
		@original_height = y
		@x, @y = x, y
		render(x,y,weight)
	end
	def render(x,y,weight)
		fill(100, 100, 200)
		no_stroke
		bezier(x, y,  x-(weight/2), y+weight,  x+(weight/2), y+weight,  x, y)
	end
	def dead?
		@y > $app.height
	end
	def run
		@y = @y + @weight
		@x = @x - rand(6)
		render(@x,@y,@weight)
	end
end

@TomK32
Hi ruby processing has move on since you posted your rain sketch to our gallery see latest developments at
https://github.com/monkstone/ruby-processing
I have updated your sketch in line with the latest version (bare sketches are preferred) we are now at ruby-1.9.3.