GLUT

GLUT provides a simple interface for opening & managing windows, and getting input from the keyboard & mouse.

It also defines a basic program structure - an event loop, with callback functions.

A callback is a function that you provide for other code to call when needed; the "other code" is typically in a library - something that you normally couldn't modify.

GLUT uses callbacks for drawing, keyboard & mouse input, and other events.
Whenever the window must be redrawn, your drawing callback is called.
Whenever an input event occurs, your corresponding callback is called.

Functions

glutInit(sys.argv)

Initialize GLUT
sys.argv is the command-line arguments

glutInitDisplayMode(mode)

Tell GLUT what GL-related options the window should have
mode is a bitwise-or'ed (the | operator) subset of:

• GLUT_SINGLE - single-buffered
• GLUT_DOUBLE - double-buffered
  
  
• GLUT_RGB - use RGB color
• GLUT_INDEX - use color indexing
  
  
• GLUT_DEPTH - allow depth-buffering

(other options exist, but we won't be using them in this class)

glutInitWindowSize(x,y)

Set the initial size of the window (in pixels)

glutInitWindowPosition(x,y)

Set the window's initial location on the screen (in pixels, from the upper left corner)

glutCreateWindow(title)

Tell GLUT to create the window. The window will not actually appear immediately.
title is the name of the window.

glutDisplayFunc(function)

Gives the name of a function to call whenever the graphics must be drawn.

glutKeyboardFunc(function)

Gives the name of a function to call whenever a key is pressed.
function takes 3 arguments - key, x, y. key is the key that was pressed; x & y are the position of the mouse when the key was pressed.

glutMainLoop()

Starts GLUT's event loop. This function never returns, so code after it will not be executed.