Sólidos solubles y acidez titulable

The client for PaSAT is the software that players use on the handheld device to play the game. The client was developed in C# using Visual Studio, and runs on any handheld device using the Windows Mobile 5 (or above) operating system. The .NET Compact Framework (a free download from Microsoft) is required for the client software to run.

The mobile client for PaSAT needed to display the custom map used to design the game, the PlayerÕs current location on that map, as well as allowing the user to view

important game status factors, perform actions, and view content and the results of actions.

Achieving all of this on the small screen offered by the PDAs used during the development of PaSAT was quite a challenge, and we opted for a tabbed interface with the map display as the primary interface and other tabs available for performing actions and viewing content.

In line the with the loose coupling between underlying game data and representation in the UI of the PaSAT server, we followed a similar path for the client software, ensuring that data stored internally could be displayed in a number of ways without excessive re-development of the mobile client interface. The core functionalities of connecting to the PaSAT server, obtaining game status updates, and allowing invocation of game actions, were implemented as a separate layer underneath the UI. This meant that we were able to modify the mobile UI to fit specific needs, as became necessary when designing the BuildIt game (see Chapter 6).

4.6.7.1 General interface design

The interface on the mobile device used a tabbed interface to allow the player to switch easily between different screens displaying different information and options, whilst maximising the use of the viewable area of the screen. Initial tests showed that this tabbed interface was easy for players to understand and use, and no problems with players switching between tabs. The tabbed interface (as used in Study 1) is shown below in Figure 15.

Figure 15: screenshot of PaSAT mobile client as used in Study 1, showing main map display and tabbed interface

4.6.7.2 Displaying the map and player position

The primary interface tab displays a portion of the current map using the same resolution as the authoring environment. The current playerÕs location is shown by a red dot, with other players shown as a blue dot. This is shown above in Figure 15.

Since the GPS hardware provides information about the accuracy of the current GPS fix, we initially intended to show this as a circle around the player dots to indicate the assumed accuracy of the position shown. However, initial tests with adult users showed that this was difficult to understand and appeared to clutter the screen rather than providing any useful information. This feature was removed.

4.6.7.3 Displaying status

Since most game status information is held on Player objects, with the current Player being the most salient source, the interface included a screen that could display the

names and values of all attributes currently set for a particular player. This screen (shown below in Figure 16) also showed in-game objects present at the playerÕs current location (which could be picked up) and the objects the player was currently carrying (which could be dropped).

Figure 16: screenshot showing display of player state and available objects

In practice this approach was found to be impractical for both the Study 1 trials and the BuildIt game. For Study 1, players did not require this status display and so the tab was removed to avoid cluttering the display. For BuildIt, players needed to see only three specific attributes (Funds, Risk, and Estimates Ð for details see Chapter 7), whilst a large number of attributes were irrelevant for them since they were internal variables for the game itself. We added a feature to allow attributes to be hidden from players on the status screen, but it was still felt that the required attributes would be better placed on the main map display so that players could always see them without

needing to navigate to a different screen. The main map display was customised for BuildIt to display the values of these three key attributes. This display queried the local Player object to obtain the current values, thus fitting in with the data representation used in the PaSAT system but indicating that more flexible ways of adding state display to the interface would be desirable in the long term.

4.6.7.4 Enabling invocation of actions

A primary mechanism for playing the games created using PaSAT was to allow players to invoke actions within the game. A tab was included that displayed a list of available actions (specific to the playerÕs current location and state). When an action was selected, options specific to that action were displayed allowing the user to enter information such as on whom the action should be performed. When the user clicked on the ÒDo it!Ó button the game server performed this action and modified the game state accordingly.

As shown in Figure 17 above, the player can select an Action from the drop-down list that then configures the options on the screen for that particular action. Here the Action ÔfreezeÕ requires the player to select a specific player as a target for the action. Other actions can be created that can act on all players, all players in the current location, or all players with a specific attribute. The Actions display changes accordingly for each Action type.