Category: Technical

Posts of a more technical nature. Nuts and bolts detail.

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File Saving Madness

Save Game

Staying true to being a ripoff of Java, C Sharp makes saving files extremely painful just as Java does.  I just want to save the player ranks and the highest level completed, which would probably be 5 to 10 lines of code in Ruby.  This is more confusing in Java, since two or three different writer classes must be created.  In XNA and C Sharp, the method for saving files is poorly documented.  There is some documentation from Microsoft on saving files, but the code is really fragmented on the page, it doesn’t explain where some of the core objects (like StorageDevice) are created, and I could never get the XML serialization to work even though I imported the  XML/Serialization references multiple times and have all the requried “using” statements in the class headers.   They do include a ZIP file of example code, but it doesn’t include the necessary references, and it is really spaghetti code because it tries to perform every single file operation known to mankind in one class file.  Therefore, it becomes an Easter Egg hunt to get it working.  The NeHe tutorials are a good example of how to properly write code tutorials.  This thread gave some additional insight on how to write save game files, but as one poster mentions it is not compatible with XBox360.  Found another tutorial, which seems to be simpler to follow since it doesn’t include all of the XML serialization, which is really overkill for what I’m trying to do now (just writing integers to a file).    This is also becoming very aggravating because it never explains how to actually get a handle to a StorageDevice instance.  These examples  just show the StorageDevice object being passed as a parameter.

Now I know how this guy feels.

So after about an hour of debugging the example StorageDemo code, I was able to get it working in a new game project (still can’t get the [Serializable] error to go away, no matter how many includes that I have, so I just commented it out).  I’m starting to think that it is not possible to display a device selection screen in an XBLIG (XBox Live Indie Game), because I don’t remember any other XBLIGs having a device selection window.  Also, I checked my XBox360 System storage settings, and there didn’t appear to be any data associated to any of the Indie games that I have played.  I know at least two of the Indie games I’ve played have had save capabilities, but maybe it was not done through the standard XBox storage device select interface.  Maybe the device selection capability is blocked in Indie games, just as the Achievement system is blocked.  The Indie games that did have saves either made saving ubiquitous or they have a custom designed save screen.  Ubiquity is great, and that is definitely the saving approach I want to take if possible.  The only problem is that it prevents the player from wiping their data from the System dashboard menu, if the player desires to start the game fresh.

Triumph

So after 4 good hours of reading unhelpful message threads, poor examples, and endless debugging, I was able to develop a solid method for saving text data to a file.  This works for both XBox360 and Windows.  The code is below.  This is ALL that is required!  I don’t have a CLUE why something this relatively simple was made so complicated in the examples!  My code could be improved by adding the ability to read multiple lines (instead of using just one single line).  Comments are welcome to improve this code, but this works for me so I’m not changing it unless there is a REALLY good reason.

Update:  I’ve learned that using a callback method with BeginShowSelector is the best way to read and write to a file.  Also, not specifying the PlayerIndex for BeginShowSelector makes things much simpler, because you don’t have to worry about if the player is signed into a profile. 

Important:  Also required is a call to  add a GamerServicesComponent to the Components collection in the constructor of the main game class.
   this.Components.Add(new GamerServicesComponent(this));

So it’s hard to capture the saving ability in a screenshot, but I now have the save method just writing the maximum level completed to the file.  Below is a fresh instance of the game started, with the max level data loaded from the save file and displayed on the screen.  The max level data was written to the file in a previous game instance.

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Spamming not Allowed

Cooldowns

Made another gameplay change today.  The fact that the player could pick a high level resistor and spam it to quickly complete the level was really bothering me.  Thefore, I added an array in the GameLevelScreen class which holds the cooldown value for each selectable piece.  When the piece is dropped, the cooldown value for that piece is set to 2 seconds (120 frames).  That value is decreased by one on each update until it reaches zero, then the user may place that resistor again.  So now the user can still use all resistors, but it will take a really long time to complete the stage, which solves the problem of the player winning the stage quickly if all resistors are used.  Using all resistors will also not give the player the best luminosity score.  I could put in a limit on how many times each resistor can be used, but I think that would over-complicate things.

Active Screen

A new abstract method has been defined in the Screen class, which is setActiveScreen.  This is a method that I already had in the TitleScreen class, but I thought it should be included in all Screen classes.  This method is called whenever the Screen gets set as the currentScreen.  Initialization that needs to be done whenever the screen gets control (such as setting pause values) can be set in this method.  This was going to be necessary for both the GameWinScreen and GameOverScreen, so I thought it was best to have it as a common abstract method.  Those two screens now have a pause instance variable that is set to the wait time in the setActiveScreen method, which prevents the player from bypassing the screen until that pause value hits zero.  This will also allow me to just call setActiveScreen on the currentScreen object once when control is passed, and I won’t have to call that method specifically for each Screen subclass instance.  I already had a setCurrentScreen method defined in the Screen class, but it is not abstract and its job is to set the next screen state to -1.  I think having the setActiveScreen abstract method handle the subclass specific code is best for now.

Title Screen Completed

Added a new background image for the currently select main menu item.  Used Gimp to create a free selection shape on top of one of the computer card images.  Used the color tools to make the image grayscale, and then increased the brightness twice.  Then I applied the bevel filter twice, and drop shadow filter once.  Also gave the currently selected item ‘s font a green color, and changed the font to Motorwerk.  Unless there is a good reason to change it again, I’m considering the title screen done.

 Loose Ends

Made a slight modification to the level complete sound effect, so the pitch gradually raises through the sound clip.

Added delay when an LED busts before moving to the Game Over screen.  The LED is now filled with red when it is busted (could use a cool breaking graphical effect later).

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Keep on Trucking

Laundry List

I’m getting the feeling that this is the point where a lot of my other game projects have died out.  A core game and fancy title graphics.  I have rarely taken the time to go back and add all the bells and whistles, such as sound effects and flashy graphical effects.  Plus, I’m really not a fan of level design.  It really feels arbitrary to me, but it does take expertise to make good levels in a puzzle style game.

Therefore, to keep myself on track I made a laundry list of the next things to complete in the game.  Some will require a little research since this is my first XNA game, such as saving the game status.

  • Hold Confirm button to keep placing wires
  • Zoom in for letters on title screen
  • Game over screen delay / graphics
  • Display level/stage before starting a level
  • Transitions between screens (such as fade out)
  • Show player ranks for stages on level select
  • Don’t allow levels that haven’t been completed to be selected on level select
  • More levels; different array sizes
  • Colored backgrounds for level screens
  • Save levels completed along with ranks
  • Render objects in Blender
  • Add graphics/sound effects on level complete screen
  • Keyboard controls so that others who don’t have XBox can play test

The first task I tackled was the hold confirm button to keep laying pieces.  This is a core gameplay change, so I felt it was most important.  Basically, I just required a new instance variable in the GameLevelScreen class, which tracks if the confirm button is being held down.  On each update, it checks to see if the button is held down, and if it is, then it tries to set a piece at the current cell.  Therefore, it is constantly trying to set a piece at the current cell (but can’t since no more than one piece can be assigned to a cell), so there may be room for optimization here later.  Anyway, the controls feel MUCH better and less jerky now with this in place.  I think I need to put a cooldown on resistor usage, because the player can select a resistor and just spam it all over the board to quickly complete the level.  It’s okay for the wires to not have a cooldown, because spamming wires will likely cause the player to bust an LED and lose.

Continuing to resolve the tasks that required the most programming first, I decided to implement the record display on the level select screen.  To do this, I had to create a PlayerRecords class, which holds the records of each completed level.  This object is populated with the level ranks after each level is completed.  The level select screen uses this to display the ranks for each level.  Currently, if a level is replayed, then the ranks are overwritten each time the level is completed, which should be fixed later.  For now, the level select screen just shows the integer values associated with each rank, but these will be changed to the rank graphics in the near future.  Plus, I will need to implement a way to scroll through the higher levels.

 

In the level select screenshot above, I played through level 1 getting ranks C, S, B.  Then I selected level 5 and got ranks S, C, B.  Noticed an error which caused the game to crash.  After completing the fifth level (level index 4), it would actually go to level index 5 (which didn’t exist but used the layout of level index 0 as default).  When that level was completed, it would go to level index 1 (level 2) next.  So it appeared that it was looping back to level 1 (level index 0), but it really wasn’t.  Therefore, when it tried to save the statistics for level index 5, it reported an error because I only allocated the array in the PlayerRecords class to hold values for five levels (level index 0 through 4).  I went ahead and added the level index to the game level display, but I will probably create a method to convert that index to a stage number.

New Levels

Next I started working on adding new levels.  Before churning out new levels in the Mappy tile editor, I wanted to make sure that new levels can be easily added to the game.  I added two new List variables to the LevelDefinition class, to hold all of the tile maps and object maps.  This will eliminate the if/elseif statement mess that was in the getter methods that return the object arrays, tile arrays, and rank arrays for the currently selected level.  I really need to create a Map object to hold those values for each level, but I don’t want to have too many classes right now, so I don’t think it’s worth the time and effort to rework that code now.  The only benefit is that it would eliminate potential problems of managing five parallel Lists, but instead it would just be one list of Map objects.  I added additional checks in each of the methods that return ranks in the LevelDefinition class, so that it doesn’t try to index a position in one of the rank arrays if the level parameter is greater than the size of one of the rank lists.  This shouldn’t ever happen unless the NUM_LEVELS constant in the LevelDefition class is set to a value higher than the size of the rank Lists.  If this happens in the object or tile array getter methods, then it just returns the array information for level 1 (index 0).  I didn’t add any checks to see if the object and tile arrays were completely empty, because I thought that would be obsessive.  I may have to think about the ability to add an expansion to the game later, which may conflict with the PlayerRecords definition.

I used the Mappy tile editor to create more levels for the game, bringing the total to 20.  I wrote a small Ruby script to loop through all the files in the map export directory, and it does some minor modifications to prepare those arrays to be used in the game, then it writes out the results so that I have all the arrays in one file instead of 40 different files.  Made another minor modification to the rank code, which was preventing it from saving the ranks for the first stage (index 0).

  

 

More Title Screen Updates

Got side tracked and spent about an hour getting the letters on the title screen to zoom in.  After all letters are displayed, then there is a 5 second pause, then the letters zoom in again.   I’m not sure how much more time I will want to spend on the title screen.  Gameplay is most important, but the title screen is the first thing that people see.  I definitely wanted to display the title screen as soon as possible.  I am so sick of seeing idiotic Game Studio Logos on startup that just waste my time.

So now I think I just need to re-do the font for the menu items to match the title font, and then have a new menu item selected image (the default tile has been there for a while).  I’m thinking of just using another portion of the computer card images that I already have, and maybe apply a brighter white color and a drop shadow.