Group Project Shaft 37-X25

Transcription

1 Group Project Shaft 37-X25 This is a game developed aimed at apple devices, especially iphone. It works best for iphone 4 and above. The game uses Unreal Development Engine and the SDK provided by Unreal, Unreal Editor for developing the game. It also has the power of coding it provides through Unreal Script programming Language. Unreal Script is an object oriented language similar to Java. My contribution to the Game has been primarily in the area of unreal scripting. I have also been a part of Unreal Visual Scripting called Unreal Kismet, with one of the fellow group mates as a pair programmer. The development environment that was used for programming was Visual Studio 2008 with nfringe, a core technology for custom language support for visual studio. This provided easy code compilation with code intellisense that boosted the development process, of an altogether new language development. I was responsible for the game controls and game play development along with a fellow group member. I was also involved in the integration of the User Interface into the game that involved scripting and the hooking up of the Unreal Kismet with the code. The block diagram bellow summarises the flow of data maintained by the Unreal Script in the Game. Unreal Kismet (Unreal Editor) Unreal Script Action Script (Flash) Bin Config files Image 1: block diagram of data flow maintained by unreal script Game controls The game controls developed in unreal script are described as follows: Tap to move: The primary control of a game is the navigation control and our game implements the tap to move control. The player walks to the place where the iphone device touch interface is tapped. This was a challenging part of the implementation as it involved many calculations like obstacle avoidance, stop walking on a second tap, and avoid walking when touched on the sky, making the tap mobile input mutually exclusive with the swipe input and so on.

2 Thus this was efficiently accomplished by pair programming with a fellow group member. Code references were used from one of the games developed using Unreal Engine. Swipe to Look: This was the next important control that enables the player to look around the world as he walks. The power of the UDK Engine could be seen here as it provides inbuilt classes, which were extended to derive essential features to achieve this. Extending the features of this into my class implementation simplified the development process. Image 2: Code snippet for tap to move and swipe to look controls Gyroscope: The Gyroscope of the device was planned as a control to look around the world with a free cam. The yaw of the Gyroscope had to be clamped to a bound so as to control the camera better. So a custom kismet action node was created to perform this check. But the swipe control was already used for the purpose of looking around the world which could not be made mutually exclusive with the gyro. So the bounds were removed and the full gyro inputs were wired to the mobile input system. Image 3: Custom Kismet Sequence Action node for gyro tilt calculation that was not used.

3 Game Play I have been part of the game development. The game play is to collect food collectibles and keep the trapped player from dying. The energy bar of the player keeps dropping at a steady rate as he is trapped inside a mine and he eventually dies if he is unable to collect enough food before he finds his exit out of the cave by solving simple puzzles like collecting pick axes and TNTs to blast open the exit. Following are the game play logics implemented: Game Health: The health of the player keeps reducing at a slow and steady rate till he reaches parts of the tunnel where it is filled with vicious gases where it reduces at twice the usual rate. If the miner manages to find his exit from such tunnels, he is given back his health; else he is doomed to die. There are also the collectibles like water bottles in the mine which he has to collect to replenish his health. The health is increased by a 10% every time he collects such collectibles. TNT collection The miner has to collect three TNT sticks to blast the exit of the mine to free the miner from the trap. An inventory is maintained on the number of TNTs collected and a trigger is enabled on success that is used by the unreal kismet. Image 4: The code snippet for the custom kismet sequence Condition, that exposes the state of TNT blast state.

4 Vicious gasses tunnel The entry and exit into the vicious gasses tunnel is maintained through a custom trigger that updates the required HUD display and pop up warning messages. Image 5: The code snippet for the custom trigger for the air tunnels that are placed in the start and beginning of the tunnels in the game. Collectibles for health replenishment With the power of unreal Engine, a custom collectible Static Mesh Actor class was created to handle the behaviour of the collectible on touch of it. The collectible disappears on touch to indicate its consumption with an increase in the health bar. Also if the health is up-to 98% full, the collectibles dose not disappears and a message appears to indicate health is full. Also, the collectibles are also re-spawned in the same place after every 60 seconds so as to keep the miner supplied with energy supplies during his wander in the mine. Image 6: The custom static mesh Actor developed for the collectibles.

5 User Interface The User Interface of the game was developed in Flash. Unreal Script proved to be very powerful for the integration of the User Interface HUD and game menus, which involved lots of data flow between Action script of Flash and Unreal script. Following are the portions of the UI handled in Unreal Script. Heads Up Display The heads up display that included updating of health bar, oxygen cylinder, warning pop ups, TNT display were handled in scripting. This was done along with the UI department members. This involved communicating between the Action Script and Unreal Script to and fro through the Unreal Engine inbuilt external interfaces. Image 7: The HUD of the game that is updated through code Options Menu: The options menu contains the Mute and Joystick controls options that require being persistent across the levels in the game play and also across different sessions of the Game. Thus the data were collected from the flash Action script and stored in configuration (binary) files and sent back to the options menu to populate the data on display. The Unreal Engines default class interfaces was used to implement this.

6 Image 8: Options Menu Flash movie- GFX movie handled in Unreal Script Pause Menu: The menus of the game were mainly handled by the kismet easily than in scripting. But the issue arose with the pause menu when the whole game freezes except the background code. So the whole pause menu sequence Restart and Main menu was handled with unreal scripting. Image 9: Pause Menu Flash movie- GFX movie handled in Unreal Script

7 Other Custom Kismet nodes Other custom kismet sequence nodes were developed as required on demand from the Unreal Scripting department. Following are the nodes developed: Set and get global state variables: Global state variables had to be saved and retrieved to be used across levels and erased on exit or restart of the game. This was handles in unreal script and exposed in the form of kismet nodes to be used by visual scripters of the game. Image 10: Set and get custom Kismet Sequence Action node for setting and getting global state variables. Game options menu: As explained above the options menu details retained in config files were sent to the Unreal kismet through this custom action node. Image 11: Custom Kismet sequence Action node to get the details set in the options menu called during on load. Console commands: Custom console commands were developed to easily wire the communication of the kismet to Unreal script.

8 Image 12: Custom console commands used for communication from kismet to unreal script. Works other than Unreal Scripting Game Cinematic research The initial research and prototype for the cinematic of the game was developed in Unreal kismet. The cinematic was later developed in Maya by other members of the group. Image 13: Initial Cinematic research and the kismet nodes

9 Level 1 layout design The lay out of the Level 1 with two floors was designed based on which the mine has been blocked and laid out. Image 14: Level 1 design Reference Cardone, R., 2011, Unreal Development Kit Game Programming with UnrealScript. Birmingham: Packt Publishing Ltd PixelMineGames, Tools:nFringe. Available from: [Accessed 20 February 2013]. Unreal Technology, Gameplay Programming. Available from: [Accessed 20 February 2013]. Unreal Technology, Mobile Input System. Available from: Kismet Touch Input Events. [Accessed 21 February 2013].