Publishers of technology books, eBooks, and videos for creative people

Home > Articles > Design > Adobe Creative Suite

  • Print
  • + Share This
This chapter is from the book

This chapter is from the book

Tiling the Maze

In this section, you'll build the game environment—the tree maze—dynamically by using ActionScript. There are many advantages to using this approach. Tiling your game field means reusing the same square graphic, which is usually 20x20 pixels, to build a map that will serve as your environment throughout the game. This is an efficient process that enables you to keep your file size small. You can also get creative and use different tiles and layering, but this depends on the complexity and sophistication of your game.

Figure 5.7Figure 5.7

This project uses two tiles to demonstrate how this concept works. The following figure shows an example of a reusable, tile-based background. You can find these tiles in the Bonus folder in the Library.

  1. Open the Tree Maze scene. You'll notice that there is nothing on the Stage other than the Score text. The Timeline has two layers: scripts and score. The scripts layer has a folder that contains all the code neatly organized in five layers: initialize, sounds, functions, actions, and listener.

Figure 5.8Figure 5.8

  1. Go to the first frame of the initialize layer. Open the Actions panel and type this script:

  2. Listing 5.2

    //Initializing variables
    
    _global.Tilewidth = 30;  //Tile width
    _global.Tileheight = 30;  //Tile height
    
    var mazeDepth:Number = 1000;  //Starting instance level
    var score:Number = 0;  //Starting score
    var winScore:Number = 0;  //End score (defined in map Array)
    var obstacle:Number = 2;  //Variable to indicate which elements are solid
    var speed:Number = Tilewidth/3;  //Variable to indicate player speed

    This script declares seven variables that are used to build the maze: Tilewidth, Tileheight, mazeDepth, score, winScore, obstacle, and speed. Speed is defined as Tilewidth/3. If you want the character to move faster, try dividing the Tilewidth by 2 instead of 3.

NOTE

Identifying a variable as _global will make it visible to every Timeline in the movie. When using _global, do not use the variable declaration (var =) syntax.

You're using _global here because constants in Flash refer to built-in values such as those associated with the Key and Math classes. By using var to declare Timeline variables and strictly typing them, you are prevented from assigning the wrong type value to the variable.

  1. Go to the actions layer. Add this script in the first frame:

    Listing 5.3

    //Create a container movie clip named 'cell' and make it the movie's root
    
    createEmptyMovieClip("cell", 1);
    cell._x = Tilewidth;
    cell._y = Tileheight;
    cell._lockroot;

    Here you create an empty movie clip through ActionScript to act as a container and define it as the root for the duration of this movie by using the _lockroot property.

    Assigning cell's x and y values to variables allows you to change the size of the maze by modifying the values associated with Tilewidth and Tileheight.

  2. Go to the functions layer. Enter this script in Frame 1:

    Listing 5.4

    /* Resource Functions */
    
    //The addSprite function attaches instances of the sprite name to the cell container.
    function addSprite(sprite, mc_name, x, y) {
      cell.attachMovie(sprite, mc_name, mazeDepth—);
      cell[mc_name]._x = x*Tilewidth;
      cell[mc_name]._y = y*Tileheight;
    }

Figure 5.9Figure 5.9

The function called addSprite takes four parameters: sprite, mc_name, x, and y. This function places all cells on the Stage, gives them a name, and assigns their _x and _y properties by multiplying x and y by the Tilewidth to position the movie clip. Depending on the order it is called will depend on what appears on top. In this version, puffin appears below the balloons. That can be changed either by placing the character on the Stage first or by changing the attachMovie parameter to mazeDepth++.

  1. Now you are ready to create the map grid. In the actions layer, add this code to your script:

    Listing 5.5

    _global.map = [[2,2,2,2,2,2,2,2,2,2,2,2,2,2,2], 
                        [2,1,0,0,0,2,0,2,0,0,0,0,0,0,2], 
                        [2,0,2,2,0,2,0,2,0,2,2,2,2,0,2], 
                        [2,0,2,0,0,0,0,0,0,0,0,0,2,0,2], 
                        [2,0,0,0,0,2,0,2,0,2,0,0,0,0,2], 
                        [2,0,2,2,0,2,2,2,2,2,0,2,2,0,2], 
                        [2,0,0,2,0,0,0,2,0,0,0,2,0,0,2], 
                        [2,2,2,2,0,2,2,0,2,2,0,2,2,2,2], 
                        [2,0,0,2,0,0,0,0,0,0,0,2,0,0,2], 
                        [2,0,2,2,0,2,2,2,2,2,0,2,0,0,2], 
                        [2,0,0,0,0,2,0,2,0,2,0,0,0,0,2], 
                        [2,0,2,0,0,0,0,0,0,0,0,0,2,0,2], 
                        [2,0,2,0,2,2,0,2,0,2,2,2,0,0,2], 
                        [2,0,0,0,0,2,0,2,0,2,2,0,0,0,2], 
                        [2,2,2,2,2,2,2,2,2,2,2,2,2,2,2]];

    Using an array, you map the maze grid cell by cell, where each number identifies a game element. This map array defines where trees, balloons, and the starting character are. These values will be used to place the character, make obstacles register as solid, and calculate the winning score. In other words, this is the "heart of the game."

  2. You now need to add these functions. Go to the function layer and enter this script right after the addSprite() function:

  3. Listing 5.6

    //The to_tile function recalculates the x and y values passed to it based on their position relative to a tile on the stage.
    function to_tile(x, y) {
      var tileX = Math.floor(x/Tilewidth);
      var tileY = Math.floor(y/Tileheight);
      return {x:tileX, y:tileY};
    }
    
    //The get_tile function, conversely, gets the identity of the tile located at the x and y positions. 
    //(returning a value of either 0, 1 or 2)
    function get_tile(x, y) {
      var tileX = Math.floor(x/Tilewidth);
      var tileY = Math.floor(y/Tileheight);
      return (map[tileY][tileX]);
    }

    The function to_tile() will be used to determine which tile the player's character is currently in. The function get_tile() will be used for collision detection with solid tiles (in this case, trees) to prevent the user from walking through them.

  4. Right-click/Ctrl-click on the tile movie clip in the Library and assign the following Linkage properties:

    Identifier: tile

    Check: Export for ActionScript and Export in First Frame

Figure 5.10Figure 5.10

  1. Go back to Frame 1 of the functions layer. Add a nested loop to populate the rows and columns of the maze grid. Then type this script:

  2. Listing 5.7

    function initTiles() {
      //Define the height and width of the maze by getting the length of each array element.
      var height:Number = map.length;
      var width:Number = map[0].length;
      //This set of nested for loops builds the maze, looping through the array and placing tiles on the stage, then 
      //assigning them values based on their position and jumping to the proper display frame (either a balloon or a tree).
      for (y=0; y<height; y++) {
       for (x=0; x<width; x++) {
         var mc_name = "t"+x+"_"+y;
         addSprite("tile", mc_name, x, y);
         cell[mc_name].p = to_tile(cell[mc_name]._x, cell[mc_name]._y);
         cell[mc_name].gotoAndStop(map[y][x]+1);
         if (map[y][x] == 0) { winScore++; }
         if (map[y][x] == 1) { charLoc = [y, x]; }
       }
      }
    }

    The initTiles() function has two local variables named height and width, which are scoped to this function. The mc_name variable is created so that Flash does not have to calculate the values for the name multiple times during the loop.

    The outer loop runs for as long as y<height of the maze (the number of rows in the map array) is true. The inner loop executes for as long as x<width (the number of columns in the map array) of maze.

    The nested loop is dynamically creating the names of the tiles t0_0, t0_1 through the total size of your array, which is t14_14 in this case. (Remember: Although there are 15 rows and columns, the array begins at 0,0.) After a name is created, you create an instance of the tile movie clip inside the cell container sitting on the Stage.

    Next there is a pair of if statements to check the current array value. If the array value is a balloon (0), the winScore variable will be incremented. This is the one you will check against to see if the player has gotten all of the balloons. If the array value is the player (1), you will generate a variable to use when we place the character in the maze.

    The following figure shows what your code should look like at this point.

Figure 5.11Figure 5.11

  1. Save your work.

  • + Share This
  • 🔖 Save To Your Account

Peachpit Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from Peachpit and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about Peachpit products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites; develop new products and services; conduct educational research; and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email ask@peachpit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by Adobe Press. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.peachpit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020