OpenGL

1
OpenGL

• Brian Farrimond
• Robina Hetherington

2
What is OpenGL

• A specification of a set of functions for drawing
  graphics
• Names of functions
• What information these use to do their job
• Description of what they do
• Software companies create implementations
• We shall use Microsoft .NET implementation

3
What OpenGL does

• Can create 2D and 3D objects made from lines,
  curves and polygons
• Can create a controllable virtual camera to view
  the objects
• Can generate realistic images of the objects as
  viewed through the camera
• Can enhance realism using lighting, materials,
  blending and fog
• etc

4
Making OpenGL easier to use

• OpenGL only deals in points, lines, curves and
  polygons
• Additional libraries are available
• GLU library provides more complex shapes e.g.
  spheres, boxes
• GLUT library provides straightforward windowing
  capability

5
OpenGL function names

• Begin with gl e.g.
• glClearColor()
• An OpenGL function can have different types of
  arguments. This is achieved by amending the name
  e.g.
• glVertex2i(7, 3)
• glVertex3f(1.0, 3.0, 7.5)

6
Installing the GLUT library

• GLUT already installed in Room FML 400
• You need to install GLUT on your home machine
• See instructions on page 7.

7
Example OpenGL Programs

• Cubes
• Texture Filters
• Loading and moving through a 3D world
• Flag waving

8
Brief intro to Computer Graphics

• Computer monitor
• 2D array of picture elements
• Cathode Ray Tube (CRT)
• Liquid Crystal Display (LCD)

9
OpenGL use of hardware
10
Scanning the display

• Full screen scan every 10 milliseconds
• (Refresh rate)

11
First OpenGL Program