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High End Visualization with Scalable Display System

ByDinesh M. Sarode,

S.K.Bose,P.S.Dhekne,

Venkata P.P.KComputer Division, BARC, Mumbai

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Introduction

Shortcomings of present graphics systems

Limited Resolution of display device Rendering Power Visualization and understanding

multi terabyte scientific data Interactivity

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Cluster based visualizationWhy ?

Current high end visualization hardware is expensive

No flexibilityNo commodity building blockNeed redesign in order to keep track

with faster semiconductor technology

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System Architecture A Cluster of PCs PC graphics

accelerator cards LCD displays

Network

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Scalable Display System at BARC Rendering Cluster

1 Master Client 16 Graphics Servers 1.7 Ghz P-IV Processors,

512 MB RAM per PC 64 MB 3Dlabs Oxygen

GVX1 Pro AGP card Fast & Gigabit Ethernet

Interconnection

High Resolution Display Tiled 4x4 LCD panels 5120x 4096 total

resolution

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Architecture Problems

• Cluster of PC No shared memory pool

• Independent graphics accelerator cardsGenlockSwap lockData lock

• Tiling Multiple monitorsseams between monitors

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The Software Environment

Client / Server Single instance of application Higher network bandwidth

Synchronized program execution Multiple instances of the application Less network bandwidth

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System Software Chromium

Framework for distributed rendering Client/Server approach Run existing OpenGL applications

DMX (Distributed Multihead X) Distributes X window sessions across

the nodes of scalable display system Run X11 applications

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Rendering Pipeline

GeometryDatabase

GeometryTransformation

Rasterization

Image

Transformation, clipping,Lighting etc

Scan-conversion, shading ,visibility

Per Vertex

Per Pixel

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Distributed Rendering

[Molnar et al. 1994]

Sort-First Sort-Middle Sort-Last

G

R

G

R

G

R

Display

Database Traversal

Preprocessing

3D Primitives

Database Traversal

Preprocessing

G

R

G

R

G

R

Display

Rendered Pixels

Database Traversal

Preprocessing

G

R

G

R

G

R

Display

2D Primitives

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Sort-First configuration

Tile 1

Tile 2

Tile 16

NETWORK

Crserver

RenderSPU

Graphics Card

Server 1

Crappfacker

Xlib TilesortSPU

Graphics Card

Client

..

.

Crserver

RenderSPU

Server 2

Graphics Card

Crserver

RenderSPU

Server 16

Graphics Card

Packed OpenGLCommands

mothership

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A view …Graphics Servers Graphics Servers

User

Graphics Data Graphics Data

1

2

5

6

9

10

13

14

4

3

8

7

12

11

16

15

1211

2 3 4

5 6 87

9 10

13 14 15 16

1

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DMX

Proxy X Server

X Application

Back-end X server Display1

DMX Console

Display2 Back-end X server

Display3 Display4 Back-end X serverBack-end X server

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Graphical Control Panel

Login/Logout X windows on all tiles Manage the cluster

Reboot / shutdown nodes Display power management Display system information Interface for running scripts across

cluster

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Applications : AnuVi

Scalar Plot

Vector Plot

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AnuVi

Isosurfaces

Ray casting

Simultaneous display of multiple datasets

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Visualization of Tsunami simulation data

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CollabCAD

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Tiled MPEG/AVI movie player

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Tiled Image Viewer

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Conclusion Scalable display system with PC

cluster is reasonable alternative to High-end multiprocessor, multi-pipe systems

Low cost & technology tracking Deep & rich visual experience Adaptable to variety of applications

& usable under various computing and display configurations

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Thanks