Introduction

EL5130-Computer Graphics & GPU Programming

Computer Graphics

• Graphics created by computer• The representation and manipulation of

pictorial data by computer

Human perception

Interactive graphics is (typically) for human viewers– Guided-missile design is a counterexample– Human will be presumed in this course

Good designers know their customers’ needs and problems– Have basic understanding of visual perception– NTSC is a great engineering design example

The evolution of computer graphics has been directed by the quirks of human perception, e.g.,– Tri-color stimulus– Sensitivity to change in light reaching the eye

Purpose of computer graphics?Communication is the purposeHuman perception is the context

– Techniques leverage visual perception abilitiesFidelity is a tool, not (necessarily) the goal

– Virtual reality is great, but– Don’t want to be limited to reality

• Want to do super reality• Non-photorealistic rendering (NPR) is valuable

– Bill Buxton, Sketching User Experiences, 2006– No apology is required for “approximations”

• Especially for interactive graphics

Color perceptionColor is perceptualStimulus is spectral energy in 400-700

nm rangeMonochromatic differentiation

requires:– Overlapping cone sensitivities

(ratios)– Only two cone types

Three cone types (a human quirk)– Enrich our perceptual

experience– Require stimulation with (at

least) three “colors”• RGB is the display tuple Normalized typical human cone cell

responses to monochromatic spectral stimuli (Source: Wikipedia)

Dual (3D Realistic) Computer Graphics & Image Processing

Representation

Model

ImageReal-World

Computer Graphics Visualization

Image Processing

Pixelsgraphics

pixel

imaging

CCD sensor (Bayer pattern)

LCD display

PixelsWhy do CCDs use the Bayer pattern?

Why don’t LCD monitors use the Bayer pattern?

What is graphics missing?– Microsoft ClearType– Claude Betrisey, Jim Blinn, Bodin Dresevic,

Bill Hill, Greg Hitchcock, Bert Kely, Don Mitchell, John Platt, Turner Whitted, 20.4: Displaced Filtering for Patterned Displays, Society for Information Display, 2000.

Basic 3D Graphics Pipeline

Scene Transformation Projection Rasterization

Model Lighting

Graphics

image (pixels)

lights (photons)

viewer

objects (triangles)

Physical reality (sort of)

image (pixels)

for (each photon)

for (each triangle)

for (each pixel)

draw;

lights (photons)

objects (triangles)

Ray tracing

image (pixels)

for (each pixel)

for (each triangle)

for (each light)

draw;

objects (triangles)

lights (photons)

Physical reality (sort of)

lights

image (pixels)

for (each light)

for (each triangle)

for (each pixel)

draw;

objects (triangles)

Traditional graphics pipeline (OpenGL)

lights

image (pixels)

for (each triangle)

for (each light)

for (each pixel)

draw;

objects (triangles)

Modern graphics pipeline (OpenGL 2.1)

lights

image (pixels)

for (each triangle)

for (each pixel)

for (each light)

draw;

objects (triangles)

Global illumination

Light paths are complex, not light triangle pixelNature finds equilibrium efficientlyComputers struggle

Animation

Sequence of still frames– Update rate: minimum of 24 hz or so– Flicker rate: minimum of 50 hz or so

“Rule 1”:All discontinuous frame-to-frame changes

correspond to discontinuous scene or visibility changes

Interactive graphics

System latency

Frame rate and flicker rate

Impact of Computers

• Moore’s Law• Power of a CPU doubles every 18 months / 2

years

Impact of Video Games (Nvidia)

• Number of transistors on GPU doubles each 6 mos.– Three times Moore’s Law

• Good article on Jen-Hsun Huang, Nvidia CEO: http://www.wired.com/wired/archive/10.07/Nvidia_pr.html

"What we've done in the past five years is staggering,“ "What we can do in the next five years is going to blow your mind. In 10 years, we should be bigger than Intel."

How is come?

Topics

• (Conventional) Computer Graphics Pipeline– Core graphics pipeline: Modeling transformation, viewing

transformation, hidden surface removal, illumination / shading / textures, scan conversion / clipping

– OpenGL– Morphing, curves and surfaces, animation, etc.

• GPU Programming• Not a course about graphic design, using graphics

tools like PhotoShop or Maya but possibly you will use it in the assignments

Prerequisites

– You will be writing programs• Non-trivial data structures, pointers

– An ability to learn a programming library on your own• OpenGL

– Comfortable with matrix algebra and calculus• Basic linear algebra

Work

– Assignment & Programming assignments (30%)• C/C++ using OpenGL, GLUT, and UI libraries• Source will be read and documentation is req’d

– Product Development Project (50%)– Final Exam (20%)

Courses Workflow

Graphics Pipeline Conventional (8 weeks)

Contemporary Issues (1-2 weeks)

GPU Programming (5-6 weeks)

OpenGL/Glut Tutorial& Assignment (8 weeks)

ProjectTuesday, 10.00 – 11.40 Wednesday, 13.00 – 13.50

http://course.lskk.ee.itb.ac.id

Honor Code

– Specific honor code instructions will be provided with each assignment

– When in doubt…• Don’t use resources other than class notes and textbook

– Typically…• Using examples from the web is a great way to learn

and it is encouraged… reference what you use– Discuss things and working together is encouraged, but– In general, it is unethical and it is discouraged to share

assignment code with another student or debug assignment code together

1st Assignment

• Single page essay on the impact of graphics cards based on an article in http://www.wired.com/wired/archive/10.07/Nvidia.html

• Why do CCDs use the Bayer pattern?• Why don’t LCD monitors use the Bayer pattern?• Why do we need ClearType™ font? How it

works?