Virtual Environments

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Transcript Virtual Environments

Virtual Environments
Vic Baker
Manager, WV VE Lab
Lecturer, WVU CSEE
What are Virtual Environments?

Let’s define Virtual Environments as
“computer generated worlds that are
represented through computer
generated imagery, audio, and humancomputer interaction”
Outline for this presentation
 Basic 3D terminology and concepts
including 3D modeling
 An explanation of Virtual Reality and
what high-end tools are currently
available such as the ImmersaDesk
and the CAVE
 Household VE platforms -- Nintendo
64 and the PlayStation gaming
consoles
Let’s start with the basics
Anti-aliasing
 Texture mapping
 Blending
 Fog
 Flat, Gouraud, and Phong shading
 Persistence Of Vision (POV)
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Anti-Aliasing

Anti-Aliasing disguises the “stair step”
effect.
Texture Mapping
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Texture mapping is the applying of a
bitmap to a wire-frame mesh. The
purpose is to add a sense of realism to
the wire-frame model.
Blending

Blending enables you to produce
translucent objects.
Fog

Fog makes objects far from the
viewpoint seem to fade in the distance.
Shading Styles

Flat vs Gouraud vs Phong shading
Persistence of Vision
Persistence of Vision (POV) refers to
how many frames per second are
required to give the illusion of fluid
motion
 24 frames per second are required to
achieve POV.
 We strive for 30-60 fps!
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Think about this ...

To create a 5 second animation with POV at
24 fps, that requires 120 separate frames!
What did you say???
With a running time of 69 minutes, Walt
Disney’s Bambi required 99,360
separate frames of animation.
 My thesis document was 120 pages and
contained 100,000 characters.
 That’s almost 1 frame for every letter in
my thesis!

Basic 3D tools and terms
Modeling packages
 OpenGL -- a programmatic approach
 Polygons to pixels … let’s talk about the
rendering pipeline

And now, a word about ...
Modeling Packages
OpenGL
The Programmatic Approach to
Graphics
OpenGL is a Programming API
that allows us to :
Draw Objects
 View Objects
 Apply Lighting
 Texture Mapping
 Perform animation
 Add Interactivity

Some OpenGL Commands
glTranslatef(GLfloat dx, GLfloat dy, GLfloat dz);
glRotatef(GLfloat angle, GLfloat x, GLfloat y, GLfloat z );
glScalef(GLfloat x, GLfloat y, GLfloat z );
glVertex3f(GLfloat x, GLfloat y, GLfloat z );
glNormal3fv(const GLfloat *v );
OpenGL demos

Windows 9x and NT have screen savers
that are created using OpenGL.
Examples are 3D Pipes, 3D Text, and
3D Flying Objects.
The Rendering Pipeline
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Pictures are made up of objects…
– Objects are made up of polygons…

Polygons are made up of vertices…
Where do we start?!?
Follow the yellow brick road!
The Rendering Pipeline

9 steps of the pipeline:
–
–
–
–
–
–
–
–
–
Read input
Backface Culling
Trivial Accept/Reject
Lighting
Viewing Transformation
Clipping
Divide by W/Map to 3D Viewport
Rasterization
Display
Virtual Reality
The Next Generation in
Visualization
Virtual Reality
Virtual Reality (VR) is the next wave in
human-computer interaction
 Virtual Reality allows us to “immerse”
ourselves into realistic 3D environments
and interact with this world

Cutting Edge VR Tools
ImmersaDesk
 CAVE
 Infinity Wall
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ImmersaDesk

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5’ x 4’ screen that
projects stereo
images
Users wear LCD
shutter glasses
Interaction is
through a wand or
speech
ImmersaDesk
WV recently acquired an ImmersaDesk
through the work of Dr. Frances Van
Scoy and the National Science
Foundation’s EPSCoR program
 Only about 3 dozen Universities and
Research centers have this technology

ImmersaDesk
Powered by an SGI Onyx 2 computer
with 4 R10000 CPUs running at 250
Mhz
 512 MB main memory
 Reality graphics board
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CAVE
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Cave Automated
Virtual Environment
Room sized VR
environment
Users wear LCD
shutter glasses
Interaction through
a wand or speech
How Do we Create Worlds?
Modeling packages
 OpenGL
 VRML
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Typical Uses for VE
Accident reconstruction
 Crime re-enactment
 Entertainment
 Scientific Visualization
 Battle simulations

Virtual Environments

Projects using the ImmersaDesk
include:
– WV Geographical Informational Systems
– Literature Land, WVU English Dept.
– WVU Physics Dept.
– Low vision and VR, Vic Baker
– NIOSH, joint research in visualization
– numerous other projects throughout the
State
Bring on the Games!
Let’s see how the Sony PlayStation stacks up
against the Nintendo 64!
Gaming Consoles
While many children (and college students)
have a gaming console in their homes, the
computational power contained in these units
is anything but child’s play.
Sony PlayStation
32 bit RISC (R3000A) running at 33
MHz
 16 Mbit RAM (Main)
 8 Mbit RAM (VRAM)
 4 Mbit RAM (Audio)
 16.7 Million colors (24 bit)
 256 x 224 (up to 640 x 480) resolution

Sony PlayStation -- How fast
can it draw?
Graphics Processor Unit capable of
360,000 flat, shaded polygons per
second
 GPU capable of 180,000 texture
mapped, Gouraud shaded polygons per
second
 Geometry Engine can process
4,500,000 vertices/second (1,500,000
polygons/sec for flat shading)

Sony PlayStation Media
Format
Games come on CD
 CD can not be easily duplicated. Bad
sectors on CD mark CD as “legit” for
PlayStation
 Sony Proprietary CD format
 Net Yaroze lets you create games for
your PlayStation using your PC

Nintendo 64
64 bit R4000 running at 93.75MHz
 36 Mbit RAM (main)
 4,500 Mbit transfer speed
 Graphics and Audio co-processor
running at 62.5 MHz
 32 bit RGBA frame buffer support
 21 bit color video output
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Nintendo 64

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CPU and Reality Co-Processor have
more than four million transistors
vector processor that can perform over
a half a billion arithmetic operations
per second
approximately 10 times the raw
compute power of some of the popular
Intel Pentiums in use today.
Nintendo 64 -- How fast can it
draw?
Pretty fast!!!
 When running Super Mario 64, the N64
is computing approx 80,000,000
adds/subs/mults per second
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Nintendo 64 Media Format
256 Mbit cartridges
 Cartridges allow for fast access but
have limited storage
 N64 Disk Drive will store 64 MB
 N64 DD will read 1 MB/sec ~~ 6X CD

Nintendo 64 Party Trivia

Amaze your friends with some pretty
cool trivia about why the N64 is so cool
Tell them about how many tax returns it could
compute in a second
 How NASA could have used it for Moon
missions
 What would happen if we networked all N64s
in the world together ….. Let’s see!
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N64 Party Trivia
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The raw computational power inside the
N64 could perform the calculations
necessary to tabulate the tax returns of
6.5 million people per second (IRS Form
1040, the long form)
N64 Party Trivia
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The Nintendo 64 has roughly 1,000
times the performance of the
computers used to land a man on the
moon.
Nintendo 64 Party Trivia
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If the Webster's dictionary was on an
N64 cartridge, the N64 could read the
entire dictionary in 1/4 of a second.
Nintendo 64 Party Trivia
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The N64 can perform 3.5 times as many
adds per second as the original Cray-1,
which cost $8,000,000 in 1976. The
Cray-1 also consumed 60,000 watts of
power, compared to the Nintendo 64
machine's 5 watts.
Nintendo 64 Party Trivia
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The N64 design team included
engineers that designed SGI
workstations, PCs, military flight
simulators, supercomputers, NASA
software systems, stereos, stadium
scoreboards, etc.
More information
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Want to learn more? Check out these sites!
– www.csee.wvu.edu/~vic/thesis/abstract.html
– www.csee.wvu.edu/~cs288
– www.csee.wvu.edu/~vanscoy/idesk.html
– 157.182.194.150 (WV VE Lab)
– www.nintendo.com/n64/hardware.html
– www.playstation.com
– www.mips.com/coolApps/s3p6.html
– e-mail -- [email protected]
– TAKE CS 288!!!!!