introduction to cg

8/13/2019 Introduction to CG

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Introduction to

Computer Graphics

CS 351


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Introduction to CG Computer Graphics involves creation,

display, manipulation and storage of picturesand experimental data for propervisualization using a computer

Typical graphics system comprises of a hostcomputer with support of fast processor,large memory, frame buffer and

Display Devices(monitors)

Input Devices(mouse, keyboard, joystick, touchscreen, digital pen, trackball)

Output devices(LCD, laser & color printers,Plotters)

Interfacing Devices(Video I/O, TV interfaces, etc)


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Conceptual Framework for

Interactive GraphicsApplicationModel

ApplicationProgram

GraphicsSystem

OutputDevice(Monitor)

InputDevices(Keyb

oard)


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What drives computer graphics? Typical Applications of Computer Graphics

Graphic al User Interfaces (GUI) interface orprogram that sits between user and graphicsapplication program.

Typical Components used in GUI MENUS

ICONS

CURSORS

DIALOG BOXES SCROLL BARS

BUTTONS

SKETCHING

3-D INTERFACESSlide information from Leonard McMillian's slideshttp://www.cs.unc.edu/~mcmillan/comp136/Lecture1/compgraf.html


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Example of a GUI available inAdobe Acrobat Reader


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Other Typical applications of CG Business Plotting Office Automation

Desktop publishing

Plotting in Science and Technology Web/Business/Commercial publishing and

advertisements

Engineering ApplicationsCAD/CAMDesign(Ex- VLSI, Constructions, Circuits)

Scientific Visualization(Effects of bombs,biological simulations, etc)

Cartography


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Other Typical applications of CG

Simulations & Simulators

Multimedia

Virtual Reality Process Monitoring(Ex- Chemical Process,

Sensors, Circuits)

Digital Image Processing

Educational and Training


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What drives computer graphics?

Movie Industry

Leaders in quality and artistry

Not slaves to conceptual purity

Big budgets and tight schedules

Reminder that there is more toCG than technology

Hey, How'd they do that?

Defines our expectations

Slide information from Leonard McMillian's slideshttp://www.cs.unc.edu/~mcmillan/comp136/Lecture1/compgraf.html


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What drives computer graphics? Game Industry

The newest driving force in CG Why? Volume and Profit

This is why we have commodity GPUs

Focus on interactivity

Cost effective solutions Avoiding computating and other tricks

Games drive the baseline

Slide information from Leonard McMillian's slideshttp://www.cs.unc.edu/~mcmillan/comp136/Lecture1/compgraf.html


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Medical Imaging and Scientific Visualization Tools for teaching and diagnosis

No cheating or tricks allowed

New data representations and modalities

Drive issues of precision and correctness Focus on presentation and interpretation of data

Construction of models from acquired data

Nanomanipulator, UNCJoe Kniss, Utah Gordon Kindelman, Utah


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Computer Aided Design Mechanical, Electronic, Architecture,...

Drives the high end of the hardware market

Integration of computing and display resources

Reduced design cyles == faster systems, sooner

ProEngineer, www.ptc.com


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Various application packages and

standards available Core Graphics

GKS

SRGP PHIGS, SPHIGS and PEX 3D

OpenGL(with ActiveX and Direct 3D)

X11- based systems(OpenGL on Linux)


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GKSGraphics Kernel System

By ISO(International StandardsOrganizations) & ANSI(American NationalStandards Institute)

Replaced by SRGPSimple RasterGraphics Package

Replaced by PHIGSProgrammersHierarchical Interactive Graphics System

Replaced by OpenGL(Open GraphicsLibrary)


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How to use OpenGL

Download Device Drivers, Library files,Header files of OpenGL for correspondingsystems i.e. either windows or Linux and

Display Adapter card that is used. Once you have compiler on top of Visual

Environment like .net in windows system ornew environment based on X11 for Linux,

you will be able to write your own graphicsprograms on OpenGL .


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Tools, Utilities and Compilers

Various utilities and tools available for web-based design includes: JAVA, XML,VRML(Virtual Reality Modeling Language)and GIF animators.

Certain compilers, such as Visual C/C++,Visual Basic, Borland C/C++. BorlandPascal, Turbo C, Turbo Pascal, Gnu C/C++,JAVA provide their own graphical libraries,

APIs, support and help for programming 2-Dand 3-D graphics.

Some of these systems are device-independent (OpenGL, X11) and device-dependent(Solaris, HP-AGL)


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Four Basic output primitives(or

elements) for drawing pictures Polylines ((x1,y1), (x2,y2).. (xn,yn) )

Filled Polygons

Ellispe(arc) (circle is a special case of ellipse) Text

Raster Image (digital images of JPEG, JPG,GIF, BITMAP ,etc format)


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Four Major Areas of ComputerGraphics

Display of Information

Design/ Modeling

Simulation and User Interfaces


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Active and Passive GraphicsSystem

CG Systems could be active or passive

In both cases, the input to the system is thescene description and output is a static oranimated scene to be displayed

In case of active systems, the user controlsthe display with the help of a GUI, using aninput device(Ex- Video Games)

In passive systems no control overdisplay(Ex- TV)


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Various Fundamental Conceptsand Principles in CG

Display Systems

Storage displays, Random scan, Raster refreshdisplays, CRT basics, video basics, Flat panel

displays TransformationsManipulating objects

Affine Transformations(2-D & 3-D) : Rotation,Translation, Scale, Reflection and Shear.

Viewing Transformation : The CameraTransformation sperspective, orthographic,isometric and stereographic views, Quaternion


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Scan Conversion and Clipping

Drawing of Points, Lines, Markers, Curves,

Circles, Ellipse, Polyline, Polygon, Area filling, fillstyle, fill pattern, clipping algorithms, anti-aliasingetc.

Hidden Surface Removal

Back face culling, Painters Algorithm, scan-linealgorithm, BSP-trees, Z-buffering/sorting, Raytracing etc.

Shading & illumination

Phongs shading model, texture mapping, bumpmapping, Gouraud shading, shadows andbackgroud, color models etc.


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Curves and Surfaces

Bezier Curves, B-Splines, Cubic-Splines,Quadratic surfaces, parametric and non-

paramertic forms, hermite curves etc.


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What is Computer Graphics?

Look at 5 areas

Hardware

Rendering

Interaction

Modeling

Scientific Visualization

Slide information from Richard Riesenfeld


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Hardware: Amazing Changes

Fundamental architecture shift

Dual computing engines:

CPU and GPU

More in GPU than CPU


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Fast, cheap GPUs

~$300

Cheap memory

Displays at low cost

How many monitors do you have/use?


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Wired -> Unwired

World of Access


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Hardware... some not so good

Devices

3D displays

Etc


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Hardware

How old is Nvidia

How big is Nvidia

QED


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Rendering

Many think/thoughtgraphicssynonymouswith rendering

Well researched

Working on second and third order effects

Fundamentals largely in place


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Rendering

Major areas:

Ealiest: PhotoRealism

Recent: Non-Photorealistic Graphics (NPR)

Recent: Image-based Rendering (IBR)


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Rendering Realism

Cornel Measurement Lab


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Rendering Realism

Real Synthetic

Shirley, et. al., cornell


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Is this real?

m fajaro, usc


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Growth Models

o deusson,


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Rendering/Modeling Hair

http://www.rhythm.com/~ivan/hairRender.html

QuickTime and aPhoto decompressor

are needed to s ee this picture.

QuickTime and a

Video d ecompressorare needed to s ee this picture.

H


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Humans

Final Fantasy (Sony) Jensen et al.


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Is Photorealism Everything?


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Is Photorealism Everything?


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Non-Photorealistic Rendering

b gooch, et.al., utah


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Tone Shading

a gooch, et. al., utah


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NonPhotorealistic Rendering


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3D Scene Capture

Fuchs et.al., UNCUNC and UVA


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3D Scene Recreation

Faugeras et. al


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360oScan

p willemsen, et. al., utah


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Interaction still needs...

Better inputdevices

Better outputdevices

Better interaction paradigms Better understanding of HCI

Bring in psychologists


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Modeling

Many model reps

Bezier, B-spline, box splines, simplex splines,polyhedral splines, quadrics, super-quadrics,

implicit, parametric, subdivision, fractal, levelsets, etc (not to mention polygonal)


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Modeling... is hard

Complexity

Shape

Specifying Realistic constraints

Detail vs concept

Tedious, slow

s drake, et. al., utah


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Modeling is hard

Mathematical challenge

Computational challenge

Interaction challenge Display challenge (want 3D)

Domain knowledge, constraints


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Growth Models

o deusson,


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Models

D Johnson andJ D St Germain, Utah

Russ Fish et al., Utah


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Scientific Visualization

Johnson et al., UtahNational Library of Medicine

Visual Human

QuickTime and a

YUV420 codec decompressorare needed to see this picture.


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In This Class

Review rasterization, modeling, viewing,lighting, texture mapping and raytracing

GUI and Interaction in three-dimensions


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Required Books

Optional


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Each class

Based-upon reading assignment

Quiz

Roundtable:

What you found to be the most interesting in thereading

What confused you or topic(s) you want morediscussion on


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Each class (cont.)

Lecture and discussion

20 minute or less viewing of an animation

Project discussion and help session

At least one 15 minute break in the middle


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Projects

C or C++

Chinese-Resturaunt menu like


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Project Rules

Failure to follow these rules will result in lostpoints:

If you use code from elsewhere, it must be

documented in your README If you use ideas from printed paper or online

material, must credit it

Projects must compile and run on thedesignated machine


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Grades

Class participation

Quizes

Late projects loose 5% on first 12 hours, 10%every 12 hours after that

You can miss

Can drop lowest quiz score

Can miss one class without loosing participationpoints


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What is Computer Graphics?

Creation, Manipulation, and Storage ofgeometric objects (modeling) and theirimages (rendering)

Display those images on screens orhardcopy devices

Image processing

Others: GUI, Haptics, Displays (VR)...

introduction to cg

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