DEFINITION AND CONCEPTS OF COMPUTER GRAPHICS
Definition of Computer Graphics. Computer graphics generally means creation, storage and manipulation of models and images. Such models come from diverse and expanding set of fields including physical, mathematical,
artistic, biological, and even conceptual (abstract) structures. “Perhaps the best way to define computer graphics is to find out what it is not. It is not a
machine. It is not a computer, nor a group of computer programs. It is not the know-how of a
graphic designer, a programmer, a writer, a motion picture specialist, or a reproduction specialist.
Computer graphics is all these –a consciously managed and documented technology directed
toward communicating information accurately and descriptively.
History of Computer Graphics. 1. The Age of Sutherland
In the early 1960's IBM, Sperry-Rand, Burroughs and a few other computer companies existed. The
computers of the day had a few kilobytes of memory, no operating systems to speak of and no
graphical display monitors. The peripherals were Hollerith punch cards, line printers, and roll-paper
plotters. The only programming languages supported were assembler, FORTRAN, and Algol. Function graphs and “Snoopy'' calendars were about the only graphics done.
In 1963 Ivan Sutherland presented his paper Sketchpad at the Summer Joint Computer Conference.
Sketchpad allowed interactive design on a vector graphics display monitor with a light pen input
device. Most people mark this event as the origins of computer graphics. 2. The Middle to Late '60's
Software and Algorithms
Jack Bresenham taught us how to draw lines on a raster device. He later extended this to circles. Anti-aliased lines and curve drawing is a major topic in computer graphics. Larry Roberts pointed
out the usefulness of homogeneous coordinates, matrices and hidden line detection algorithms.
Steve Coons introduced parametric surfaces and developed early computer aided geometric
design concepts. The earlier work of Pierre Bézier on parametric curves and surfaces also became
public. Author Appel at IBM developed hidden surface and shadow algorithms that were pre- cursors to ray tracing. The fast Fourier transform was discovered by Cooley and Tukey. This
algorithm allow us to better understand signals and is fundamental for developing anti-aliasing
techniques. It is also a precursor to wavelets. Hardware and Technology
Doug Englebart invented the mouse at Xerox PARC. The Evans & Sutherland
Corporation and General Electric started building flight simulators with real-time raster
graphics. The floppy disk was invented at IBM and the microprocessor was invented at Intel. The
concept of a research network, the ARPANET, was developed.
3. The Early '70's
The state of the art in computing was an IBM 360 computer with about 64 KB of memory, a
Tektronix 4014 storage tube, or a vector display with a light pen (but these were very expensive). Software and Algorithms
Rendering (shading) were discovered by Gouraud and Phong at the University of Utah. Phong
also introduced a reflection model that included specular highlights. Keyframe based animation
for 3-D graphics was demonstrated. XeroxY7U PARC developed a ``paint'' program. Ed Catmull
introduced parametric patch rendering, the z-buffer algorithm, and texture mapping. BASIC, C, and Unix were developed at Dartmouth and Bell Labs. Hardware and Technology
An Evans & Sutherland Picture System was the high-end graphics computer. It was a vector
display with hardware support for clipping and perspective. Xerox PARC introduced the Altos
personal computer, and an 8 bit computer was invented at Intel. 4. The Middle to Late '70's
Software and Algorithms
Turned Whitted developed recursive ray tracing and it became the standard for photorealism, living
in a pristine world. Pascal was the programming language everyone learned. Hardware and Technology
The Apple I and II computers became the first commercial successes for personal computing. The
DEC VAX computer was the mainframe (mini) computer of choice. Arcade games such as Pong
and Pac Mac became popular. Laser printers were invented at Xerox PAR
5. The Early '80's
Hardware and Technology
The IBM PC was marketed in 1981 The Apple MacIntosh started production in 1984, and
microprocessors began to take off, with the Intel x86 chipset, but these were still toys. Computers with a mouse, bitmapped (raster) display, and Ethernet became the standard in
academic and science and engineering settings. 6. The Middle to Late '80's
Software and Algorithms
Jim Blinn introduces blobby models and texture mapping concepts. Binary space partitioning
(BSP) trees were introduced as a data structure, but not many realized how useful they would
become. Loren Carpenter starting exploring fractals in computer graphics. Postscript was
developed by John Warnock and Adobe was formed. Steve Cook introduced stochastic sampling to
ray tracing. Paul Heckbert taught us to ray trace Jello(this is a joke;) Character animation became
the goal for animators. Radiosity was introduced by the Greenberg and folks at Cornell. Photoshop
was marketed by Adobe. Video arcade games took off, many people/organizations started
publishing on the desktop. Unix and X windows were the platforms of choice with programming
in C and C++, but MS-DOS was starting to rise. Hardware and Technology
Sun workstations, with the Motorola 680x0 chipset became popular as advanced workstation a in
the mid 80's. The Video Graphics Array (VGA) card was invented at IBM. Silicon Graphics
(SGI) workstations that supported real-time raster line drawing and later polygons became the
computer graphicists desired. The data glove, a precursor to virtual reality, was invented at NASA.
VLSI for special purpose graphics processors and parallel processing became hot research areas. 7. The Early '90's
The computer to have now was an SGI workstation with at least 16 MB of memory, at 24-bit raster
display with hardware support for Gouraud shading and z-buffering for hidden surface removal. Laser printers and single frame video recorders were standard. Unix, X and Silicon Graphics
GL were the operating systems, window system and application programming interface
(API) that graphicist used. Shaded raster graphics were starting to be introduced in motion pictures. PCs started to get decent, but still they could not support 3-D graphics, so most programmer's wrote
software for scan conversion (rasterization) used the painter's algorithm for hidden surface removal, and developed “tricks”' for real-time animation.
Software and Algorithms
Mosaic, the first graphical Internet browser was written by xxx at the University of Illinois,
National Center for Scientific Applications (NCSA). MPEG standards for compressed video began
to be promulgated. Dynamical systems (physically based modeling) that allowed animation with
collisions, gravity, friction, and cause and effects were introduced. In 1992 OpenGL became the
standard for graphics APIs In 1993, the World Wide Web took off. Surface subdivision algorithms
were rediscovered. Wavelets begin to be used in computer graphics. Hardware and Technology
Hand-held computers were invented at Hewlett-Packard about 1991. Zip drives were invented aIomega. The Intel 486 chipset allowed PC to get reasonable floating point performance. In 1994,
Silicon Graphics produced the Reality Engine: It had hardware for real-time texture mapping. The
Ninetendo 64 game console hit the market providing Reality Engine-like graphics for the masses of
games players. Scanners were introduced.
8. The Middle to Late '90's
The PC market erupts and supercomputers begin to wane. Microsoft grows, Apple collapses, but
begins to come back, SGI collapses, and lots of new startups enter the graphics field.
Software and Algorithms
Image based rendering became the area for research in photo-realistic graphics. Linux and open
source software become popular. Hardware and Technology
PC graphics cards, for example 3dfx and Nvidia, were introduced. Laptops were introduced to the
market. The Pentium chipset makes PCs almost as powerful as workstations. Motion capture, begun
with the data glove, becomes a primary method for generating animation sequences. 3-D video games become very popular: DOOM (which uses BSP trees), Quake, Mario Brothers, etc. Graphics effects in movies becomes pervasive: Terminator 2, Jurassic Park, Toy Story, Titanic,
Star Wars I. Virtual reality and the Virtual Reality Meta (Markup) Language (VRML) become
hot areas for research. PDA's, the Palm Pilot, and flat panel displays hit the market.
9. The '00's
Today most graphicist want an Intel PC with at least 256 MB of memory and a 10 GB hard
drive. Their display should have graphics board that supports real-time texture mapping. A flatbed
scanner, color laser printer, digital video camera, DVD, and MPEG encoder/decoder are the
peripherals one wants. The environment for program development is most likely Windows
and Linux, with Direct 3D and OpenGL, but Java 3D might become more important. Programs
would typically be written in C++ or Java. What will happen in the near future -- difficult to say, but high definition TV (HDTV) is poised to
take off (after years of hype). Ubiquitous, untethered, wireless computing should become
widespread, and audio and gestural input devices should replace some of the functionality of the
keyboard and mouse. You should expect 3-D modeling and video editing for the masses, computer vision for
robotic devices and capture facial expressions, and realistic rendering of difficult things like a
human face, hair, and water. With any luck C++ will fall out of favor. ETHICAL ISSUES
Graphics has had a tremendous affect on society. Things that affect society often lead to ethical and
legal issues. For example, graphics are used in battles and their simulation, medical diagnosis, crime re- enactment, cartoons and films. The ethical role played by a computer graphic is in the use
of graphics programs that may be used for these and other purposes is discussed and analyzed in the
notes on Ethics.
APPLICATIONS OF COMPUTER GRAPHICS
1. Medical Imaging
There are few endeavors more noble than the preservation of life. Today, it can honestly be
said that computer graphics plays an significant role in saving lives. The range of application
spans from tools for teaching and diagnosis, all the way to treatment. Computer graphics is tool in
medical applications rather than an a mere artifact. No cheating or tricks allowed.
2. Scientific Visualization
Computer graphics makes vast quantities of data accessible. Numerical simulations frequently
produce millions of data values. Similarly, satellite-based sensors amass data at rates beyond our
abilities to interpret them by any other means than visually. Mathematicians use computer graphics
to explore abstract and high-dimensional functions and spaces. Physicists can use computer graphics
to transcend the limits of scale. With it they can explore both microscopic and macroscopic world
3. Computer Aided Design
Computer graphics has had a dramatic impact on the design process. Today, most mechanical and
electronic designs are executed entirely on computer. Increasingly, architectural and product designs
are also migrating to the computer. Automated tools are also available that verify tolerances and
design constraints directly from CAD designs. CAD designs also play a key role in a wide range of
processes from the design of tooling fixtures to manufacturing.
4. Graphical User Interfaces (GUIs)
Computer graphics is an integral part of everyday computing. Nowhere is this fact more evident
than the modern computer interface design. Graphical elements such as windows, cursors, menus, and icons are so common place it is difficult to imagine computing without them. Once graphics
programming was considered a speciality. Today, nearly all professional programmers must have an
understanding of graphics in order to accept input and present output to users. 5. Games
Games are an important driving force in computer graphics. In this class we are going to talk about
games. We'll discuss on how they work. We'll also question how they get so much done with so
little to work with.
6. Entertainment
If you can imagine it, it can be done with computer graphics. Obviously, Hollywood has caught on
to this. Each summer, we are amazed by state- of-the-art special effects. Computer graphics is
now as much a part of the entertainment industry as stunt men and makeup. The entertainment
industry plays many other important roles in the field of computer graphics. WHAT IS INTERACTIVE COMPUTER GRAPHICS?
User controls contents, structure, and appearance of objects and their displayed images via rapid
visual feedback.
Basic components of an interactive graphics system
1. Input (e.g., mouse, tablet and stylus, force feedback device, scanner, live video streams…), 2. Processing (and storage), 3. Display/Output (e.g., screen, paper-based printer, video recorder, non-linear editClick here to know html tags chat✍️or.
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