Feedback on new rain script

[deValdr]

Basically, I wrote a script for new rain visuals. I am going to use it in my game so it is not for reuse at this point. Feedback?

Code:

class Scene_Map  
  alias old_init_valdred initialize
  def initialize
    old_init_valdred
    @weather = Sprite.new
    @weather.bitmap = Bitmap.new(640,480)
    @weather.z = 99998
    @t = Sprite.new
    @t.bitmap = Bitmap.new(640, 480)
    @t.bitmap.font.color = Color.new(0,0,0)
    @t.bitmap.draw_text(0,0,640,20,"Not for use. Not for redistribution", 1)
    @t.bitmap.draw_text(0,460,640,20,"Save-Point.org - Valdred", 1)
    @t.z = 99999
  end
  def draw_rain
    # Reset bitmap
    @weather.bitmap.clear
    # Draw rain
    for i in 1..60
      c = Color.new(225,225,225,100)
      x = rand(640)
      y = rand(480)
      w = 1
      h = rand(75) + 10
      @weather.bitmap.fill_rect(x, y, w, h, c)
      # Extend weather
      y += rand(25)
      h -= rand(5)
      c.alpha -= rand(80)
      @weather.bitmap.fill_rect(x, y, w, h, c)
      # Add splash
      bitmap = Bitmap.new(32,32)
      bitmap.set_pixel(12,14,Color.new(225,225,225))
      bitmap.set_pixel(13,16,Color.new(225,225,225))
      bitmap.set_pixel(14,15,Color.new(225,225,225))
      bitmap.set_pixel(14,18,Color.new(225,225,225))
      bitmap.set_pixel(15,18,Color.new(225,225,225))
      bitmap.set_pixel(16,18,Color.new(225,225,225))
      bitmap.set_pixel(17,18,Color.new(225,225,225))
      bitmap.set_pixel(15,17,Color.new(225,225,225))
      bitmap.set_pixel(17,17,Color.new(225,225,225))
      rect = bitmap.rect
      @weather.bitmap.blt(x, y + h, bitmap, rect, 150)
    end
  end
  alias update_old_valdred update
  def update
    update_old_valdred
    draw_rain
  end
end

[MGC]

That's a lot better than the basic rain effect.
I noticed two things however :
1. there's an area on the top of the screen where splashes don't appear (their y coordinates are rand(480) + rand(75) + 10 + rand(25) - rand(5) : to have a small value all the three first random numbers must be small).
2. splashes appear on "vertical" elements, such as tree trunks or fronts of houses, though it seems that it's raining vertically. Perhaps you could use terrain tags to filter tiles where splashes can be displayed.

Oh, and for the coding part, I hope you'll use a picture for splashes, because using set_pixel to draw always the same thing is rather low.

[deValdr]

I am using a picture, I transcribed it into pixels for easy set up on here :)

Thanks a lot for helpful feedback. I don't remember why I did that with the splashes. I will definitively do what you said about the terrain tags.