Perspectives, Frame Rates and
Resolutions: It's all in the Game
Mark Claypool
Worcester Polytechnic Institute
Worcester, MA, USA
Kajal Claypool
MIT Lincoln Labs
Lexington, MA, USA
http://www.cs.wpi.edu/~claypool/papers/perspective/
Computer Games and Performance
•
•
Latest computer games push capabilities of hardware
in “quest” for more detailed, realistic graphics
Single game runs on varied hardware
•
Key factors for game performance are:
– PC : Old (600 MHz P3, 32 MB Video) or New (4 GHz P4, 512 MB Vid)
– Platform: PC, Console (i.e. Xbox), Hand-held (i.e. PSP)
– Result: Uneven hardware capabilities, opportunities for
performance tuning
– Frame Rate – higher frame look smoother, provide
more temporally precise feedback
– Frame Resolution – higher resolutions look better,
provide more visually precise feedback
FDG, Orlando, FL, USA
2
Motivation
•
Unfortunately, often cannot have both high Frame
Rate and high Frame Resolution
– Ex: Hand-held devices have constrained resources (small
screens, limited power)
– Ex: Older computers (often, only 1 year!) cannot run latest
games at maximum frame rate or resolution
•
Tradeoff between Frame Rate and Frame Resolution
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How are frame rates and resolutions chosen?
– Higher resolutions mean lower frame rates and vice versa
– Game console designers and hand-held designers choose
resolution for user
• Frame rate may depend upon processing load
– PC gamers choose it by “feel”
– Can we guide by science?
FDG, Orlando, FL, USA
3
Related Studies
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Passive Users [1,10,12,20,22,24,25]
•
Active Users [14,15,16,18,23]
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Games [3,5]
•
– Users assess video with various frame rates and
resolutions
– Generally, decrease resolution decreases perceived
quality, but decrease in frame rate less so
– Users perform tasks under various frame rates and
frame resolutions
– Generally, extremely low frame rates impact
performance, but frame rates of 5+ acceptable
– Different than video: frame rate matters, not
resolution
– But First Person Shooters only
Our goal – Effects of Frame Rate and Frame
Resolution on User Performance for Games
FDG, Orlando, FL, USA
4
Effects of Frame Rate and Resolution
• Impact of frame rate and resolution
depends upon action in the game
– Consider fundamental actions: shooting and
navigating
• Hypotheses
1. Shooting greatly impacted by frame rate
2. Navigating less impacted by frame rate
3. Resolution has little impact on player
performance
4. 1-3 hold across game genres based on
camera perspectives
FDG, Orlando, FL, USA
5
Outline
• Introduction
• Game Perspectives
• Approach
• Results
• Conclusions
FDG, Orlando, FL, USA
(done)
(next)
6
•
Game Perspectives
Based on:
– placement of camera with respect to the avatar
– visual change in object sizes relative to camera
First Person Linear
Third Person Isometric
FDG, Orlando, FL, USA
Third Person Linear
7
Methodology
• Develop games
• Build test harness
• Setup environment
• Solicit users
• Analyze results
• Disseminate (this talk )
FDG, Orlando, FL, USA
8
Game Development
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•
•
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Implementation using Game Maker w/stock art
Three games (1st, 3rd linear, 3rd isometric)
Two levels (navigating and shooting) for each game
Normalized so rates of shooting and navigating same
across genres
Third Person
Isometric
FDG, Orlando, FL, USA
First Person
Linear
9
Third Person
Linear
•
•
•
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Test Harness
In Visual Basic
Tutorials on navigation
level, shooting level
36 game sessions (3
perspectives, 4 frame
rates, 3 resolutions)
– 15 seconds each session
– Took ~15 minutes total
Questionnaire at end
of each session
FDG, Orlando, FL, USA
10
Experiment Environment
• Campus computer lab
• Dell Precision 380 Computers
–
–
–
–
Pentium D 3.0 GHz Dual Core
Dell 1907 Flat Panel displays
2 GB of RAM
Monitor resolution 1280x1024 pixels
• Users kept at least one computer apart
– Reduce distraction from adjacent people.
FDG, Orlando, FL, USA
11
User Solicitation
• Flyers posted around campus
• Oral announcements in courses
• Email to various student groups
• Enticed with:
– Raffles for $25 Best Buy gift certificates
– Extra credit for select academic courses
FDG, Orlando, FL, USA
12
Outline
• Introduction
• Game Perspectives
• Approach
• Results
–
–
–
–
(done)
(done)
(done)
(next)
Demographics
Navigating
Shooting
Perception
• Conclusions
FDG, Orlando, FL, USA
13
User Demographics
• 27 users
• Most CS undergraduates
• 89% male
• 74% 16-25 years
• 60% played 6+ hours of games per week
– Time correlated with user performance
• 25% casual gamers
• 50% hardcore or almost hardcore
FDG, Orlando, FL, USA
14
Navigating versus Frame Rate
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Distinct trendlines  suggests 3rd isometric easiest
Slight increase with frame rate for 1st and 3rd linear
FDG, Orlando, FL, USA
15
Navigating versus Resolution
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Distinct trendlines
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Flat with resolution
Shooting versus Frame Rate
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3rd isometric highest, easiest to locate target
1st and 3rd linear overlap
“Knee” at 15 f/s (7 f/s unplayable for 1st and 3rd linear)
FDG, Orlando, FL, USA
17
Shooting versus Resolution
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Distinct 3rd iso
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18
Flat with resolution
Playability and Quality
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•
•
•
Conclusions
Frame Rate larger impact on performance than
Resolution
– Frame Rate critical for adequate game performance
• Marked drop in performance below 15 fps
– Resolution has little effect on user performance
• Users as effective from 800x600 to 1280x1024
– Holds across all perspectives and actions
Frame Rate and Resolution both important for
user perception
– Playability mirrors frame rate
– Quality slight upward trend with resolution
Dramatically different previous research on video
– Showed converse, that Resolution mattered more
– Suggests challenges in designing devices for games and
video
FDG, Orlando, FL, USA
20
Perspectives, Frame Rates and
Resolutions: It's all in the Game
Mark Claypool
Worcester Polytechnic Institute
Worcester, MA, USA
Kajal Claypool
MIT Lincoln Labs
Lexington, MA, USA
http://www.cs.wpi.edu/~claypool/papers/perspective/