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Space Pirates: The Quest For More Booty
Frank Lesniak
Introduction In the beginning, our team envisioned a fabulous game - similar to the classic Solar Winds. It would be a 2D space flying game that incorporated missions and a trading/money system. Once we began coding our project, we immediately found that such a task would be impossible in the time we had allocated. Thus, we have instead worked toward a game-ready engine that could easily be used to create a mission-based storyline complete with a trading system. The data structures are all in place - all that needs to be added is the story itself. Our engine has many applications besides space games. It is not hard to envision the same engine being used for a Zelda-like game. Instead of a space ship, you have Link. Instead of bullets/missiles, you have a sword. Instead of asteroids, you have a forest (trees). The missions and monetary system would not be difficult to implement. Thus, our goal is to create a fully working 2D data structure/graphics engine to be able to be used to create a mission-based game with some system of trade.
We are using Orkut (http://www.orkut.com) to collaborate via the Internet.
Data Structures Sparse Array
Star Array
AsteroidObject
StarObject (NOT in "space" sparse array - EXIST ONLY IN STAR ARRAY)
Pickups/Bullets/Missiles/Lasers:
Planets:
Ships:
Code Inspection/Testing: The code will be checked by each one of us, and since it is fairly modular it will be easy to check the test cases for one object, and then apply those principles to the rest of the similar objects. We will be sure to test each function as it is written.
MAIN LOOP PSUEDO CODE _InstallHandlers Allocate Memory for Data Structures Initialize Data Structures Initialize Game Flags Create Universe Evaluate Game Flags & Jump to appropriate code section ControlLoop: _DisplayMenu Evaluate menu choice: If Resume set space mode flag else if load set load flag else if save set save flag else if new game set new game flag else if quit set quit flag jmp to EvalGameFlags SpaceLoop: Mask GameFlags so that we only have bits 6 & 5, shift right so that it is 0, 1, 2, 3 -> SpeedChange Mask GameFlags so that we only have bits 8 & 7, shift right so that it is 0, 1, 2 -> DirectionChange _ChangeVelocity(*OurShip, word SpeedChange, word DirectionChange) Set GameFlags' bits 8, 7, 6, & 5 to 0 //Fireweapon/Drop Code Here //AI Code Here NULL -> CurrentObject .UpdateSpaceLoop _FindNextObject(CurrentObject) -> CurrentObject If CurrentObject=NULL then jump to .Draw _IsMoving(CurrentObject) -> DirectionObjectIsMoving If DirectionObjectIsMoving=-1 //Not moving then jump to .UpdateSpaceLoop _MoveObject(CurrentObject, DirectionObjectIsMoving) _CheckCollision(CurrentObject) -> (ObjectCollidedWith, Type) //Priority goes to bounce before absorb If Type=Nothing then jump to .UpdateSpaceLoop If Type=Bounce _BounceUpdate(CurrentObject, ObjectCollidedWith) Jump to .UpdateSpaceLoop If Type=Absorb _AbsorbUpdate(CurrentObject, ObjectCollidedWith) Jump to .UpdateSpaceLoop .Draw _DrawBackground _DrawStarsToBuffer _DrawCloseObjectsToBuffer //_DrawStatusBarToBuffer, etc _CopyBufferToScreen End of Space Loop (return to tick control)
Control Loop New call _GenerateUniverse set flag to control mode Load call _LoadGame set flag to control mode Save call _SaveGame set flag to control mode EvalGameFlags check game mode flags if space mode jmp SpaceLoop else if control mode jmp ControlLoop else if load jmp Load else if save jmp Save else if new game jmp New else if quit jmp Quit End of Control Loop (return to tick control) Planet Loop not yet implemented... will handle/evaluate users choice based on mouse clicks, etc will handle trading/item exchanges will handle communication/conversation End of Planet Loop (return to tick control) Quit: _UninstallHandlers exit to dos
Major Sections of our Program: Space (movement, collision, object pickups, etc) Planet Mode (trade, get missions, drop off/pickup mission objects, etc).
Functions (Major): _InstallHandlers - Installs Keyboard, Mouse, Timer, etc. ISRs _UninstallHandlers - Removes Keyboard, Mouse, Timer, etc. ISRs _DisplayMenu - Displays a menu of choices for the user, according to which game flags are set obj* _FindNextObject(obj*) - Finds the next object in the sparse array after the passed in object. Returns a pointer to that object short _IsMoving - Check's an object's status to see if it is moving on this cycle. Returns 1 if so. (long, obj*) _DetectCollision(obj*) - Returns collision type and object pointer to object that this object is colliding with) _BounceUpdate(obj1*, obj2*) - Update both obj1's and obj2's information to according to a bounce _AbsorbUpdate(obj1*, obj2*) - Figures out which of two objects gets absorbed and deletes it from Space _MoveObject(obj*) - Moves the object in the direction specified by its velocity vector _FireWeapon(obj*, keypress) - Creates appropriate weapon (according to keypress) in front of obj with a velocity at least that of the obj (same direction) _ChangeVelocity(obj*, keypress) - Changes the object's velocity (direction, too) according to keypress _UpdateBackground(viewershipobj*) - Updates the background _MapBackground - Maps the Background to the video buffer [objects*] _FindScreenObjects(viewershipobj*) - Finds all the object within a radial distance of the ship and returns them in a pointer to an array _MapScreenObjects - Map the screen by finding all objects within a radial distance of the viewer's ship and putting them on the screenbuffer in their respective locations _UpdateOverlay - Updates the screen's overlay _MapOverlay - Maps the screen's overlay to video buffer _DrawScreen - Copies the video buffer to the video memory _GenerateUniverse - Creates objects at random locations in the sparse array _LoadGame - Loads a game _SaveGame - Saves current game
Some Complicated Algorithms: Insertion Algorithm
Deletion Algorithm
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