Basic GLUT library

• Here is a complete online manual.
• FreeGLUT is the newest and actively supported implementation of GLUT.

Window initialization

• glutInit(int *argc, char **argv)
  • initializes GLUT library
• glutInitWindowSize(int width, int height)
• glutInitWindowPosition(int x, int y)
  • specifies size, position of window to be created by next glutCreateWindow
• glutInitDisplayMode(OR'd bit string args)
  • specify display mode: some include...
    • GLUT_RGBA, GLUT_INDEX: rgb, color map modes
    • GLUT_SINGLE, GLUT_DOUBLE: single, double buffering
    • GLUT_DEPTH: depth buffer
• int glutCreateWindow(char *name)
  • create window specified by the above
  • integer ID for window returned
• glutSetWindow(int), glutGetWindow(int)
  • set or get the specified window (via ID number)

Callback registration

• glutDisplayFunc(void (*func)(void))
  • assigns function to call when current window must be redisplayed
• glutReshapeFunc(void (*func) (int width, int height))
  • function to call when current window is reshaped; the parameters are the new size of reshaped window
• glutIdleFunc(void (*func)(void))
  • function to call when no activity occurring (eg. for animation)
• glutKeyboardFunc(void (*func)(unsigned char key, int x, int y))
  • sets key processing routine
  • x and y are mouse coordinates when the key 'key' was pressed
  • see glutGetModifiers for state of modifier keys (eg. ctrl,...)
• glutMouseFunc(void (*func)(int button, int state, int x, int y))
  • mouse function callback
  • button: GLUT_LEFT_BUTTON, GLUT_MIDDLE_BUTTON, GLUT_RIGHT_BUTTON
  • state: GLUT_UP, GLUT_DOWN
  • x, y: mouse coordinates
• glutMotionFunc (void (*func)(int x, int y))
  • function to call when mouse is moving in window, when a button is pressed
• glutPassiveMotionFunc(void (*func)(int x, int y))
  • function to call when mouse is moving in window, when no buttons are pressed
• glutMainLoop(void)
  • starts GLUT processing; should be called only once in program

Colour Map Management

• glutSetColor(int index, GLfloat red, GLfloat green, GLfloat blue)
  • set index to specified colour
• GLfloat glutGetColor(int index, int component)
  • gets colour in index, specified by component GLUT_RED, GLUT_GREEN, GLUT_BLUE

Misc

• glutGet(GLenum state)
  • gets a particular GLUT state value
  • eg. GLUT_WINDOW_WIDTH, GLUT_WINDOW_BUFFER_SIZE, etc
• glutPostRedisplay(void)
  • marks current window as needing redisplay by glutDisplayFunc
• glutSwapBuffers(void)
  • Swaps buffers when doing double buffering during animation

Examples

Basic examples.

Advanced examples (local access only)

Online GLUT manual

Glut manual (PDF)

Short Glut article : see how to make multiple windows, menus, etc.

COSC 3P98 Computer Graphics
Brock University
Dept of Computer Science

Copyright © 2021 Brian J. Ross
http://www.cosc.brocku.ca/Offerings/3P98/course/lectures/OpenGL/glut_ref.html
Last updated: January 19, 2021