1 SuperCY Group Dec Dec or-

Team Members Paul Danner – Leader Taylor Gehling – Communications Austen Gregor – Key Idea Holder Trevor McCormack – Webmaster Manimaran Govindarasu – Advisor/Client 2 Dec14-04

Scope of Project Initial Create testbed to implement network optimizations over Android based system Optional Goal: Integrate with Union Pacific Multimedia Wall Modified Made integration with media wall mandatory Removed network optimization goal Iowa State University3

Reasons for Project Re-specification To attract potential students and show them what current students are capable of creating Lay a foundation for future apps looking to utilize the multimedia wall Give department something fun and exciting to show on multimedia wall Iowa State University4

Demo Iowa State University5

App Overview- SuperCY Side-scrolling shooter game Shoot at hordes of enemies, resulting in boss battle Multiplayer – Potential for up to 20 players Powerups add competitive element to game Interacts with media wall for unique experience Iowa State University6

Screenshot of App Iowa State University7

Unity Game Engine for variety of platforms – Android, iOS, PS3, Xbox, Windows/Mac Handles much of back end programming Focused around GameObjects – Players, background objects, scenery, etc. – Write scripts (C#, JS) to control the various GameObjects Iowa State University8

Application Design – Stage I – Singleplayer Created GameObjects to represent player/enemies Write C# scripts to control behavior of various GameObjects – Health – Movement – Shooting/collisions Unity provides means for modularization of GameObjects – i.e. Health script attached to each enemy/player Iowa State University9

Modularization CY Player Script Move Script Weapon Script Shot Script Move Script Health Script Photon View Script Cy Network Script Iowa State University10

Powerups – Challenges Singleplayer – How to get a powerup to spawn on an enemy death – Doesn’t need to spawn on each enemy death – random Multiplayer – Disallowing multiple players to obtain single powerup – Disallow multiple spawning of same powerup – Caused by technical network latency of GameObject Destroy Iowa State University11

Powerups – Solution Singleplayer – Add XYZ_powerup_module for each powerup Sprite renderer – Graphic for powerup to spawn Powerup_Script – Controls collision and corresponding actions – On each enemy death, generate random number to determine if powerup needs to spawn Multiplayer – Assign boolean within powerup scripts, keep track of collisions – On first collision with player Set boolean to false to disallow other players to interact with it Iowa State University12

Application Design – Stage II – Multiplayer Iowa State University13 Integrated Photon Unity Networking into singleplayer project Modify how game runs across multiple devices – Player/Enemy Spawning – Player/Enemy Shots – Player/Enemy Movement Modified game settings to accommodate media wall

Character Spawning Treat media wall as host of game – Spawn enemies/boss – Synchronize background Treat each Android device as client of game – Spawn character – Update movement/shots across network Host and client interact across Photon Cloud and RPC messages Iowa State University14

Networking Breakdown Photon Instantiated Objects Player movement/shots Boss movement/shots Level Synchronization Player Score/Ammo/Health RPC Enemy damage/destruction Player joining/leaving game Call a function on networked object Iowa State University15

Synchronization – Challenge Player movements getting relayed to other devices – Very jittery & delayed Player/enemy shot collisions & destruction – Because enemies were spawned locally on each device via RPC call, object collision was not uniform across network Boss health/spawning across devices – Delay caused by network transmissions cause player shots to last longer Iowa State University16

Player Synchronization – Solution Linear Interpolation – Method of “curve fitting” using linear polynomials Used to smooth out player movement across devices – Player sends updated position periodically – Other devices receive, and take average over a time frame to smooth out other player movements Iowa State University17

Collision/Destruction – Solution Updated enemy spawning to only spawn one character across the network – Pro: Much easier to synchronize states – Con: Enemy position messages increases network traffic When one device damages enemy, send RPC to all users – If enemy health is low enough, make host “Network Destroy” object Keeps all device’s levels synchronized within technical delay time Iowa State University18

Boss Synchronization – Solution Player bullets would hit multiple vertices before being “network destroyed” – Cause each bullet to cause additional damage to boss Caused by technical network delay in message transmissions Updated shot mechanics to cause it not to make more than one damage to enemy/boss Iowa State University19

Garbage Collection – Challenge GameObjects that were not in use anymore would build up and drastically reduce game performance – Issue with both Single and Multiplayer development Examples – Enemies that weren’t destroyed would continue forever – Bullets that missed would continue forever Iowa State University20

Garbage Collection – Solution Attach a frame counter to each GameObject – Count the number of frames since instantiation After ‘X’ amount of frames, destroy the GameObject Example 60 fps – Enemy will cross screen from right  left in 4 seconds if (enemy crosses screen without being destroyed) Destroy ( GameObject ) at frame_count = (60 * 4 + buf) Iowa State University21

Testing Test early, Test often – After each small addition to game logic, test using controlled level variables – Able to isolate problems easily by manipulating level – Make use of Debug Logs Beta-test – FAN Club – Let students test our game on media wall – Received feedback from testers – Observed game from developmental perspective Iowa State University22

Questions? Thank you for your time Iowa State University23

BACKUP SLIDES Iowa State University24

Menu Diagram - Note Like functional decomp in 491 project Iowa State University25

HW/SW Technology Software Unity Game Engine – Used to create Android application – Utilizes C# scripts written by user to complement traditional game mechanic backing Photon Unity Networking – Unity backed network support for multi-player apps – Cross-compatibility between different devices i.e. Windows, Android, iOS, etc. Hardware Android Devices – Up to 20 devices concurrently Union Pacific Multimedia Wall – Runs Windows 7 – 12 touch screen monitors – Located in Coover East Entrance Iowa State University26

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