gameplay and design issues in outdoor augmented reality games

Gameplay and Design Issues

in

Outdoor Augmented Reality Games

SPEAKERS:

Assoc. Prof. Bruce Thomas Director of Wearable Computer Lab, UniSA Chief Technical Officer, a_rage pty ltd

Dr. Wayne Piekarski, Assoc Director, WCLDirector of Research, a_rage pty ltd

Benjamin Avery UniSA Computer and Information Science Honours student, WCLLead Game Programmer, a_rage pty ltd

Joe Velikovsky Creative Director & Game Design Lead, a_rage pty ltd

OVERVIEW: 3 AR Game Case Studies

ARQuake – Assoc Prof Bruce Thomas

3-D Moon Lander & the ARAGE Hardware – Ben Avery

3-D Sky Invaders – Joe Velikovsky

Gameplay & Design Issues

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Outdoor Augmented Reality Games

Case Study: ARQuake

Assoc. Prof. Bruce Thomas, WCL UniSA

What do people like & dislike about ARQuake?

• What aspects of the game should be highlighted?

• What should be avoided?

ARQuake in a nutshell:

• Built in 2000, first `Outdoor AR GPS’ game• Take a desktop pc First-Person-Shooter game

and modify it - to be used as an indoor/outdoor AR game.

• Track the user’s head orientation and position in an indoor/outdoor setting.

• Player, NPCs (Critters, Monsters), & Game Objects (Health, Guns, Armour, Ammo) are all rendered normally.

• Model physical buildings - and render the game walls black, co-located with physical walls.

• Black will appear transparent in HMD to the user, but the rendered black graphics will occlude monsters, critters and game objects.

• Virtual walls, corridors, pillars, and doors are all still rendered.

• As the user walks around the physical world moving their head, the game will update with this orientation and position information.

ARQuake in a nutshell:

Original/Desktop Quake

Augmented Reality:

Non-AR View:

AR View:

Example Critters:

Quake vs ARQuake

demon

New textures

Old textures

enforcer

soldier

zombie

ARQuake

In-Game Footage:

Video 1

Field of View (FOV)

• FOV of the HMD was 24 degrees horizontal– Necessitated excessive head-turning by the

users. – thought to be “extremely narrow”.

• FOV of 90 degrees – commented that this felt much better. – Registration problems.

• FOV of 120 degrees. – “weird”; difference in parallax:physical virtual - uncomfortable.

Visuals That Worked Well

• Floating objects worked well: – “they looked like they belonged in the

game world.” – Users simply accepted them as part of

the game.

• One effect the users liked was flames: – “the fire in ARQuake looked pretty good”

and “it looked genuinely like fire.”

Walking Around• Users were able to walk through the virtual

walls.– “Walking through walls, while being an interesting

idea….. It looked solid, but I wasn't worried about walking through it because I knew that there was a room on the other side. Strangely enough, I didn't want to go out the other side….”

• One user noticed at one point, they were physically walking up a hill, but the game depicted flat ground. They stated it seemed to feel, while unexpected, easier to walk up because it looked flat.

Interaction

• Users experienced difficulties picking objects up.

– Objects “tantalizingly” within arm’s reach, but could not be picked up.

– This problem became quite frustrating for some of the users.

• Opening and closing doors - not difficult • Flying monsters require the correct

weapon and strategy

Conclusion:• Users overall, enjoyed ARQuake• Issues with Field Of View. • Small orientation errors - quite noticeable. • The standard shape of doors & corridors in

Quake worlds - not well-suited to ARQuake.• The world feels better to the user, if it is

brightly-lit. • Use of skybox/sky colour should be avoided. • Users did not like the use of shadows. • Floating objects work quite well in ARQuake.

A Study of Performance of Consumer Level Hardware

forOutdoor Augmented Reality

Gaming

by Benjamin AverySupervisor: Assoc Prof Bruce

ThomasAssoc. Supervisor: Dr Wayne

Piekarski

This Presentation:

• Background• AR On-The-Cheap• Game Technology• Example AR Game: 3D Moon

Lander• Conclusion

a-rage

• Research for a-rage AR game dev company

• a_rage & ITEK provided scholarship for studies

Background:

• Augmented Reality is: the overlay of computer-generated images onto the real world, using a Head Mounted Display

Other Indoor AR Games

Examples of Indoor AR games:

• AquaGauntlet• AR2Hockey• MIND-WARPING• TouchSpace• etc

Indoor is Easy:• Trackers can be tethered• Very accurate trackers available• Controlled environment

Image courtesy polhemus.com

Outdoor is Harder:

• Unpredictable environments• Lower-accuracy trackers• Limited computer power• Limited power• Mobility and reliability• OST vs VST HMDs

Outdoor AR Games

Only two real examples:– ARQuake– Human Pacman

…I want one at home?

• Expensive systems exist• Accurate tracking(50cm), high-

resolution, compact• Cost: AU$20,000• Too expensive for

kids to play games on!• Need a consumer-

level alternative

The Question:

Can AR games be designed and implemented, in such a way as to make them playable on low-performance level hardware?

AR `On-The-Cheap’

Our consumer-level hardware system:

Possible cost: ~$500

What problems does this cause?

• Cheap GPS is only accurate to 5 meters• Trackers ‘drift’• PAL/NTSC resolution• Limited input

so:• in your backyard

is not yet possible…

Game Design vs AR Technology!

• Make the game fit the hardware limitations– eg. OST - ‘ghosts’ in Ghosts of Sweet Auburn

• GPS ‘snap-to’ grid system, with hysteresis• Picking the correct tracker• Avoid registration with the real world

3-D Moon Lander

• Example AR game - demonstrating the concepts• Based on 1979 Atari game Lunar Lander - and pc

clones

GPS Snap-To:

Video

Conclusion

• Many games can be designed to work on this hardware platform

• Problems do exist, but careful Game Design can work around these

• We have tested the system outdoors and the GPS snapping and tracker work well

• Further play-testing by a_rage will reveal any other problems this system may offer, which we can then improve on.

AR Game Design

• joe velikovsky [Game Design Lead]

game designer former national games market analyst, InformBACS, AFTRS JOETEEVEE.COM10 years in the games industry

HMV PROTOTYPE

Design Elements• 3-D AR `port’ of Space Invaders• 5 m GPS =

– 2 locations 5m apart • (Turret & Bunker)

• Immersive game space = N,W,E,• Flames & floating objects

= UFO FPS! Set in 1950’s

• UI = intuitive = HMV is pointing deviceas per ARQuake

• Content = TV set!• Directional sound• Dev cycle = short

TURRET 5mBUNKER

5m GPS

In-Game Video

AR OUTDOORS/INDOORS

IDG 2003 GAMES INDUSTRYWHITE PAPER "I hope that peripheral companies start to look at opportunities for getting the joystick out of peoples’ hands and doing something different, - or getting us away from the TV screen with something like Head-Mounted Displays. I would love to see someone take on this challenge of establishing a real virtual environment with the power that the new consoles should provide."

Ted Price, CEO, Insomniac GamesSpyro, Ratchet & Clank

from IDG 2003 Games Industry White Paperp. 94-95

DESIGN PHILOSOPHY

1) Port `hit’ games over to AR [Space Invaders: Old Games, New Platform]

2) K.I.S. - Keep It Simple! [Games low on Graphics / high on Gameplay]

3) Play-Balance/Flow Theory - `Challenge & Reward’

4) 10 Mini-games (like EyeToy bundle)

5) Risk management - Shorter Dev Cycle! Later: bigger budgets, and longer games

GAME DESIGN

1) USER-FOCUSED GAMES (`Plug & Play’)

2) SIMPLE ADDICTIVE GAMEPLAY = FUN FACTOR

3) HIGH REPLAY VALUE

4) Age: 15+ - for physical co-ordination

5) SAFETY - in goggle view is never `off’

Shoot-em-up: 3-D

Arcade Platform

Adventure Puzzle

Sports Action

RTS

THEME PARKS & ARCADES

WHY A.R. PLATFORM?

1) POSITIVE SOCIAL ASPECT (Multiplayer)

2) ACTIVE GAMING OUTDOORS = Healthy

3) BROAD AGE & GENDER APPEAL = Adults, M & F

4) FOLLOWS MOBILE GAMING TREND (e.g. cell phone games, GBA, N-GAGE PSP)

5) ADVANCES the gaming `State of the Art’

6) Look & Feel = instant appeal/looks awesome

CONSUMER HMV

Q & A