Transcript Yard Wars
Yard Wars David Greer Alex Gross Ahsen Uppal Goals • Wireless, Portable Development • Real Time Voice Conferencing • Exciting, Expandable Game Engine Wireless, Portable Development • Real-time, asynchronous networking between many clients, using TCP/IP • Client/server architecture in emBedded and Visual C++, using MFC • Found and improved Microsoft bugs: – CCeSocket – CAsynch + Csocket – MFC Key Handler Real Time Voice Conferencing • Account for network delays by buffering on both ends, handling network problems gracefully. • Use non-blocking calls to avoid long waits. • Minimize delay between recording and playing by separating the threads. • Manage time delays between users by maintaining input and output queues. Exciting, Expandable Game Engine • Object-oriented model for all components: users, scenery, background, flags. • Uses GAPI, the Pocket PC Game API, for full control of all parts of the user interface. • Easily upgradeable to include sprites (animations), sound effects, and other features. System Specifications • Tested for Two-Player Mode • Code is fully expandable, but our group was only provided with two clients to test. • Wireless Voice Communications • Nominal two second delay • Zero packet loss, using dynamic buffering • Game Engine Response Time • Multi-threaded, event-driven program waits for data before updating state. • Since the system spends most of its time waiting for data, it can manage all threads more efficiently. Dynamic Buffering Avoiding the Readers/Writers Problem OnReceive: • Allocates new memory for each incoming audio packet • Adds new packet to the tail of a priority queue (stream), unique to each player OnTimer: • Checks all streams for data • If !empty, adds packet to buffer • If buffer full, send to clients • Clean up memory Low-Delay Send / Record Minimizing Delays in Transmission OnReceive: • Adds packet into twosecond buffer • When two-second buffer fills, play buffer OnTimer: • Finishes recording • Sends recorded buffer (non-blocking!) • Starts Recording Modular Game Engine Error Correction, Rules Enforcement, Communication Error Correction: • Boundary Checking (edges, flag oasis, trees) • Safe Zones / Sides Rules Enforcement: • Capturing Opponents / Flags • Distance Calculation Communication: • Creates character matrix with symbols ($, -, 1, 2 …) which correspond to graphics in the game • Handling each player’s moves, rules, and transmitting data between client and server. • Player Screen vs. Server Screen DEMO