First time here? First time here? Newsletter Signup Newsletter
Login | Register | 651326 Members and growing!
Search tutorials
Author: Patrick Mineault | Website: http://dakar.netqcca.com

Movie 2: The pixelated fade-in effect

I'm sure you've all seen this in Powerpoint or Director but this nice effect is rarely seen in Flash: random pixels of an image appear successively until the entire image is shown. Although there are some difficulties associated with randomization, this effect is still simple enough to grasp conceptually that it may be shown here. Using a "maskee" movie clip as with the previous movie, you may add the following script to clip:

onClipEvent(load)
{
  numY = 26;
  numX = 120;
  numPerFrame = 12;
  currSquare = 0;
  choices = new Array();
  for(i = 0; i < numX*numY; i++)
  {
    choices.push(i);
  }
	
  _root.createEmptyMovieClip("mask", 0);
  this.setMask(_root.mask);
	
  function drawSquare(x,y)
  {
    with(_root.mask)
    {
      moveTo(x,y);
      beginFill(0x000088)
      lineTo(x+5,y);
      lineTo(x+5,y+5);
      lineTo(x,y+5);
      endFill();
    }
  }
}
onClipEvent(enterFrame)
{
  if(currSquare < numX*numY)
  {
    for(i = 0; i < numPerFrame; i++)
    {
      j = random(choices.length);
      t = choices[j];
      choices[j] = choices[choices.length - 1];
      choices.pop();
      x = t % numX;
      y = Math.floor( t / numX );
      drawSquare(x*5, y*5);
    }
    currSquare += numPerFrame;
    this._alpha = currSquare/(numX*numY)*100;
  }
}

Now if you test the movie you should get a nice pixelated fade in effect: 5x5 pixel squares successively appear randomly on the screen. Now I don't expect you to understand every detail of the preceding script but it should give you some hints on using dynamic masks to create fade-ins.

The main difficulty consists of randomly choosing the squares that will be drawn on a given turn. Squares are numbered from the top left. An array is created called choices which initially contains the numbers of all the squares. At some point in the enterFrame event, an element in the array is randomly picked and kept in memory. A switch is made with the last item in the array and the array is popped, meaning the last element is removed. Then this square is drawn on the screen.

As you see this script uses basically the same drawing routine as the previous one but in a different context. It uses the same trick as the first movie in creating the mask: as long as the clear function is not called, everything that is drawn in the target clip is kept in memory and all subsequent shapes add up. This gives us a nice fade-in effect.

» Level Advanced

Added: 2004-03-26
Rating: 8 Votes: 15
(10 being the highest)
» Author
Always looking for a new challenge, I'm going to Senegal this summer to lend my computer skills in a volunteering project. I'm sending you this tutorial as part of my fundraising campaign, see http://dakar.netqcca.com . Enjoy!
» Download
Download the files used in this tutorial.
» Forums
More help? Search our boards for quick answers!

Comments

  • There are no comments yet. Be the first to comment!

  • You must have javascript enabled in order to post comments.

Leave a Comment
  • Your email address will not be published. All fields are required.
Featured Flash FLA
» Author: work2survive
» Title: Girl Walking 1kb
» Description: Walking girl, animation just takes 1kb, using high heels shoes, and fashion model attitude.
Featured Sound Loops
Image for equalize

Audio Player

» Author: BoxCat
» Title: CPU Talk
» Description: From the cyberpunk RPG, "Nameless: the Hackers" Completely Free to use! Keywords: edm hip hop rap electronic mysterious mission hacking chase exciting spy ios ambient chilling love happy sad angry suspense
Latest Font
» Author: Fábio FAFERS
» Description: I created this font for free use. Everyone can apply it in personal or business texts. Its free, but I want to be communicated in case of business use. Donations are accepted to keep the project of free fonts alive! Thank you all
Featured Sound Fx
Image for equalize

Audio Player

» Author: nathan
» Description:

A recorded sound of the Dimensional Fork Gate.