Fading a graphic in and out

[alexanderpas]

my last question for today... (23:59 here ) how can i gradually make a graphic fade in and out... like it's flashing effect...

 

[alexanderpas]

bump

 

[linkz0r]

That´s the normal way i do that kind of effect (please read all carefully):

# Suppose we have in a scene a sprite that may appear 
# and disappear at some conditions, defined in the screen. First, let´s create
# the sprite:

class Scene_Map
  attr_accessor :fade
  alias old_main main
  def main
    @sprite = Sprite.new
    @sprite.z = 9999
    @sprite.opacity = 0
    @sprite.bitmap = RPG::Cache.battler("001-Fighter01", 0)
    # Set to start with a fade in effect
    @fade = 1
    @timing = Graphics.frame_rate
    @max_opacity = 255
    @min_opacity = 0
    old_main
    @sprite.dispose
  end
end

#-----------------------------------------------------------------------
# @sprite is your actual sprite that will be shown in the screen.

# @fade is the variable that will be holding the method the sprite 
# will fade
#    - a value of 0 means no fading method
#    - a value of 1 means a Fade In
#    - a value of -1 means a Fade Out

# @timing is in frames and defines the time the fade effects will last. 
# In our case it´s set to 1 second, so to make it 2 seconds, do 
# @timing = Graphics.frame_rate * 2, or even a half second, 
# @timing = Graphics.frame_rate / 2. You say how many time you want.
# You can even put directly a defined number of frames, it´s up to you.

# @min_opacity is the minimum opacity the sprite can have

# @max_opacity is the maximum opacity the sprite can have

#------------------------------------------------------------------------
# Now that the variables have been defined, let´s go to the real
# fade effect
class Scene_Map
  alias old_update update
  def update
    old_update
    @sprite.update  # No real need to update it, but let´s follow the rules ^^
    # This is the total opacity variation for the sprite
    opacity_range = @max_opacity - @min_opacity
    case @fade
    when -1
      # The Fade Out Effect
      @sprite.opacity -= opacity_range / @timing if @sprite.opacity > @min_opacity
      @fade = 0 if @sprite.opacity <= @min_opacity
    when 1
      # The Fade In Effect
      @sprite.opacity += opacity_range / @timing if @sprite.opacity < @max_opacity
      @fade = 0 if @sprite.opacity >= @max_opacity
    end
  end
end

# In this example, if the @fade variable is set to 0 it does nothing, 
# because no fade effect was selected. If @fade is 1,  it does the
# Fade In effect, and in that case it adds a constant 
# (opacity_range / @timing) to the opacity while it´s less than the 
# maximum opacity value (@max_opacity). In case that the 
# @sprite.opacity becomes bigger than the max. value, the effect is done, 
# and the @fade is set to 0 again. The same happens with the Fade Out
# effect, but in the opposite way.
# In this example you can even cancel or change the effect in any time.

For example, copy and paste all that code in any script above main and below Scene_Map, and make three events on the map, that call those commands:
Event 1

$scene.fade = -1

Event 2

$scene.fade = 0

Event 3

$scene.fade = 1

And try to play wit them for a while ^^ You can use this concept in any kind of script that has a constant update.

I hope you got it...