Lecture 1_ Computer Graphics _Chapter 1 Introduction

COMPUTER GRAPHICS Dr. Zeeshan Bhatti

BSIT-PIV

Chapter 1Institute of Information and Communication Technology

University of Sindh, Jamshoro BY: DR. ZEESHAN BHATTI 1

Course Details

Course Code: ITEC 612-613

Course Title: Computer Graphics

Lecturer: Dr. Zeeshan Bhatti, [email protected]

Schedule: Monday and Thursday 8:30-9:15

Refered Book

Computer Graphics: Principles and Practice in C, by J. D. Foley, A. Van Dam, S. K. Feiner, J. F. Hughes.Hardcover, 1200 pages, Addison-Wesley Pub Co; 2nd edition,

Course web page:

https://sites.google.com/site/drzeeshanacademy/

Blog:

http://zeeshanacademy.blogspot.com/

Facebook

https://www.facebook.com/drzeeshanacademyBy: Dr. Zeeshan Bhatti 2

SENG-620 Artificial Intelligence and Computer Vision

Course overview: Introduction to Computer Graphics; display memory; generation of points, vectors, shapes, objects, etc.; raster and geometric graphics; interactive and passive graphics; graphics peripherals; analog and digital images and analog/digital conversion; mathematics of 2-D and 3-D transformations; applications in animation, computer aided design and instruction; hypertext and multimedia; dialog design; user-interface.

Prerequisites: Programming Fundamentals, Data Structures, Mathematics, Linear Algebra.

Grading: 10 marks: Attendance

10 marks: Assignment

30 marks: Midterm

50 marks: Final Exam

By: Dr. Zeeshan Bhatti 3

Why Study 3D Computer Graphics?

Systems: Write complex 3D graphics programs (real-time scene in OpenGL, offline raytracer)

Theory: Mathematical aspects and algorithms underlying modern 3D graphics systems

This course is not about the specifics of 3D graphics programs and APIs like Maya, Alias, DirectX but about the concepts underlying them.

Applications (discussed next)

Fundamental Intellectual Challenges

Some content inspired by Pat Hanrahan from Stanfords CS148

Applications

CAD - Computer Aided Design (Mechanical, Architectural)

Simulators (Flight, Driving, Sports)

Advertising

Virtual Reality

Architectural Visualization

Art and Entertainment

Games

Special effects

Education

Scientific visualization


Entertainment

Movies: Brave, Pixar 2012

Entertainment

Games: Halo 3, Bungie 2007

Lighting Simulation

Interior Design

Automobile Visualization

Computer Aided Design

Interiors Professional

Mechanical CAD

Architectural CAD

Electronics CAD

Casual Users

Google Sketchup

Visualization: Science and Medicine

Visible Human Project: University of Hamburg

Virtual Reality

VR for design and entertainment

Simulators: Surgical, Flight, Driving, Spacecraft

Digital Visual Media

From text to images to video (to 3D?)

Image and video processing and photography

Multimedia computers, tablets, phones

Flickr, YouTube, WebGL

Real, Virtual Worlds (Google Earth, Second Life)

Electronic publishing

Online gaming

3D printers and fabrication

Why Study 3D Computer Graphics?

Applications (discussed next)

Fundamental Intellectual Challenges

Create and interact with realistic virtual world

Requires understanding of all aspects of physical world

New computing methods, displays, technologies

Technical Challenges

Math of (perspective) projections, curves, surfaces

Physics of lighting and shading

3D graphics software programming and hardware

The Visual Sciences


The Visual Sciences

Image Processing:

From Images to Images

Computer Vision:

From Images to Models

Computer Graphics:

From Objects to Models (Geometric Modeling).

From 2D/3D Models to Images (Rendering).

From 4D Models to Images (Animation).


3D Graphics Pipeline

Modeling Animation Rendering

Geometric Modeling

From a concept (or a real object) to a geometric representation on a computer

Example: a sphere can be described as (x,y,z,r)

Complex objects can be constructed from simpler ones


Curves for Modeling

Rachel Shiner, Final Project Spring 2010

Animation

Definition of complex time-dependent behaviour of objects

Issues with rigid and elastic joints

Realistic rendering of collective behaviours

Examples:

Automatic interpolation between key-frames

Physics based simulation


Rendering

Given a scene and viewing parameters, produce an image

Images are a 2D array of pixels

Important sub problems:

Which pixels are covered by each object ? (Scan Conversion)

What is visible at each pixel ? (Visible Surface Algorithm)

What color should a pixel be ? (Illumination, Shading Algorithms).


Rendering and Image Synthesis Examples

Collage from 2007

Interactive 3D Graphics

Final Project

Rendered Image


Viewing Transformation Pipeline


Viewing Factors

Objects:

Geometrical Properties of an Object (Solid Modeling)

Physical Properties of Objects Surfaces

(Illumination Models, Color Models)

Camera:

Projections

Light Source:

Color Theory

Spatial set-up:

3D Transformations, Coordinate Systems


2D Drawing

Goal: Getting Acquainted with Images

Displays (Raster vs. Vector)

Basic Definitions: Pixel, Resolution, Dynamic Range

Line Drawing (Incremental and Mid-Point Algorithms)

Techniques for Drawing Circles

Filling Polygons


2D Transformations

Goal: Introduction to 3D, Review Linear Algebra

Basic 2D Transformations: Translation, Scaling, Rotation, Shear.

Composition of Transformations and Transformation

Groups:


2D Transformations

Transformations in Matrix notation:

Composition of transformations in matrix notation

The homogeneous coordinates in 2D:

Change of coordinates:


2D Viewing

Goal: Introduction to 3D and some Rendering Concepts

Viewing Transformation pipe-line:

Line and Polygon Clipping:


3D Viewing

Goal: Geometrical Transformations in Viewing Pipeline

From Model Coordinates to Viewer Coordinates:


3D Viewing

Projections:

Orthographic

Oblique

Perspective

The Viewing Volume:


Solid Modeling

Goal: Learn how to Define Solid Objects

1D Curves in 3D

Primitive based: line segments.

Free form:

Implicit, Explicit, Parametric (Polynomials, Splines)

2D Surfaces in 3D

Primitive Based: Polygon Mesh

Free Form: As Above

3D volumes in 3D

Volume Rep.

Sweep Volumes

Spatial Occupancy (Voxels, Octree, )

Constructive Solid Geometry

Boundary Rep.

Polyhedra

Free Form: As AboveBy: Dr. Zeeshan Bhatti 33

Solid Modelling


Parametric Surfaces

Bilinear Interpolation

Splines:

Cardinal Spline

Hermite Spline

Bezier Spline

B Spline


Color Theory

Goal: Understanding what a color is

The Trichromatic Color Theory

Linear Color Space and Color Representations: RGB,CMY,HSB

Perceptual Color Spaces: LAB,YIQ

The CIE Chromaticity Diagram


Illumination Models and Shading

Goal: Understanding the physical properties of an object

Light Source Parameters (Shape, Position, Color, Intensity)

Surface Parameters: Ambient, Diffuse, Specular

Polygon Rendering Methods

Transparency

Shadow


Illumination Models and Shading


Example: Creating an Image from a Model


Polygonal Model Generated from Spline Patches.

Orthographic Projection



Polygonal Model Generated from Spline Patches.

Orthographic Projection



Depth Cueing


Depth Clipping


Colored Vectors


Visible Line Determination


Visible Surface Dtermination with Ambient

Illumination


Individually Shaded Polygon with Diffuse

Reflection


Gouraud Shaded Polygon with Diffuse

Reflection


Gouraud Shaded Polygon with Specular

Reflection


Phong Shaded Polygon with

Specular Reflection


Curved Surfaces with Specular

Reflection


Multiple Lights


Texture Mapping


Shadows


Reflection Mapping

Example: Polynomial Texture Maps

From:

http://www.hpl.hp.com/research/ptm/


Example: Polynomial Texture Maps

From:

http://www.hpl.hp.com/research/ptm/

By: Dr. Zeeshan Bhatti56

Thankyou

Q & A


Referred BookComputer Graphics: Principles and Practice in C, by J. D. Foley, A. Van Dam, S. K. Feiner, J. F. Hughes.Hardcover, 1200 pages, Addison-Wesley Pub Co; 2nd edition,

For Course Slides and Handoutsweb page:

https://sites.google.com/site/drzeeshanacademy/

Blog:http://zeeshanacademy.blogspot.com/

Facebook: https://www.facebook.com/drzeeshanacademy

Lecture 1_ Computer Graphics _Chapter 1 Introduction

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Transcript of Lecture 1_ Computer Graphics _Chapter 1 Introduction