Computer Graphics Lecture Notes

Course Description:

• Introduction to techniques for constructing 2D and 3D graphics using OpenGL.
• Topics include:
  • Rendering pipeline
  • Primitive drawings
  • Geometric transformations
  • Clipping
  • Lighting and illumination
  • Color models
  • Texture mapping
  • Ray-tracing animation

Course Content Overview:

1. Overview of computer graphics concepts
2. CRT, spots and lights, raster and random scan displays, color models
3. Color CRT monitors, flat CRT, and Video controller systems
   • Raster and vector graphics.
4. OpenGL program and structures, Windows, points, coordinate system
5. Primitive objects and fill colors in OpenGL
6. Line drawing techniques:
   • DDA algorithm
   • Bresenham’s algorithm
7. Circle drawing techniques:
   • Midpoint circle algorithm
   • Bresenham’s algorithm
8. 2D/3D transformations:
   • Translation, scaling, shearing, rotation
   • Affine transformations
9. 2D/3D deformation techniques:
   • Shearing, tapering, twisting, bending
10. Model view transformations
11. Light and shadow rendering techniques

Prerequisites:

• Install C++, OpenGL, GLUT (Free Glut).
• Basic linear algebra and analytic geometry.

Assessment Breakdown:

• Quiz: 10% (Week 4 and Week 10)
• Course Project: 25% (Week 14)
• Participation: 5%
• Midterm Exam: 20% (Week 7)
• Final Exam: 40%

Understanding Images:

• An image is a combination of objects, lights, and a viewer.
• Methods for acquiring digital images include:
  • Scanner
  • Digital cameras
  • Computer graphics

Image Synthesis:

• Refers to the construction of images from scratch.
• Rendering refers to the synthesis of 2D images from a 3D scene description.

What is Computer Graphics?

• Definition: Creation, storage, and manipulation of models and images by a computer.
• Involves generating 2D images of a 3D world represented in a computer.
• Tasks include:
  • Modeling: Creating and representing geometry.
  • Rendering: Generating 2D images from 3D objects.
  • Animation: Describing how objects change over time.

Differences Between 2D and 3D Graphics:

• 2D Graphics: Flat images, with (x, y) color values.
• 3D Graphics: Objects have depth, represented by (x, y, z) coordinates.

Importance and Applications of Computer Graphics:

• Rapid and economical production of pictures using computers.
• Wide range of applications:
  • Graphics presentation
  • User interfaces
  • Image processing
  • Virtual reality
  • Games and entertainment

Applications in Detail:

• Data Visualization: Used in scientific, business, and medical fields to analyze complex processes.
• Graphs and Charts: Visual representation of statistics and data.
• Computer-Aided Design (CAD): Used in engineering and architectural design processes.
• Virtual Reality: Creating interactive 3D environments.
• Training Applications: Simulations for pilot and ship captain training.

Computer Graphics vs. Computer Vision:

• Computer Vision (CV): Focuses on extracting useful information from images and analyzing it.
• Computer Graphics (CG): Deals with synthesizing images from models using algorithms.

Key Components of a Graphics System:

1. Input Devices (e.g., mouse, keyboard)
2. Central Processing Unit (CPU)
3. Graphics Processing Unit (GPU)
4. Memory
5. Frame Buffer
6. Output Devices (e.g., monitors)

Input Devices:

• Physical:
  • Keyboard, pointing devices (mouse, light pen, etc.).
  • Touchscreens, graphic tablets, image scanners.
• Logical:
  • String device, locator, widget, valuator.

Graphics Processing Unit (GPU):

• Specialized circuit for manipulating and accelerating image creation in a frame buffer.

Frame Buffer:

• Storage area for images, represented as a 2D array (matrix of 0s and 1s).

Raster Scan Displays:

• Display images as discrete points (pixels) refreshed line by line.

Random Scan Displays:

• Draw images using geometrical primitives based on mathematical equations.

Color CRT Monitors:

• Utilizes phosphors to display colors; methods include beam penetration and shadow mask.

Display Technologies:

1. CRT
2. LCD
3. OLED
4. Various display devices like monitors and projectors.

Drawing in OpenGL:

• Utilize functions like glBegin, glEnd, glVertex2i etc. to create shapes.
• Draw points, lines, triangles, quads, and polygons using OpenGL commands.