
Building these GLUT programs requires Sam Leffler's free TIFF library
(libtiff).  You can find out about libtiff from:

  http://www.sgi.com/Fun/tiff/tiff-v3.4beta018/html/index.html

The libtiff source code distribution can be downloaded from:

  ftp://ftp.sgi.com/graphics/tiff/

You can get a copy of the TIFF 6.0 specification (PostScript or
Acrobat) from:

  ftp://ftp.sgi.com/graphics/tiff/TIFF6.ps.Z
  ftp://ftp.adobe.com/pub/adobe/DeveloperSupport/TechNotes/PDFfiles/TIFF6.pdf

NOTE:  SGI developers with the ImageVision development option installed
already have libtiff available if they have ifl_eoe.sw.c++ and
ifl_dev.sw.c++ installed.

Here's a brief description of the programs in this directory:

  showtiff.c - A simple TIFF viewer that uses glDrawPixels.  Use the
     pop-up menu to select between several different image processing
     operations (some of these assume you have OpenGL imaging
     extensions).

  writetiff.c - An example writing out an OpenGL rendered image as a
     TIFF file.  Several compression schemes can be selected.  Use the
     pop-up menu to write the file.  You can view the resulting
     gears.tif with the showtiff program.

  textiff.c - A TIFF viewer that renders the TIFF image via texturing
     so that the image can be rotated.  Use the left and right arrow
     keys to rotate the image.

  depthdof.c - A sophisticated OpenGL image processing-based technique
     developed by Jon Brandt (SGI) that simulates a depth-of-field
     effect using a depth-varying convolve.  When you click on a point
     in the scene, the focus point is set to that depth.  Objects at
     the same depth should appear clear; object further or nearer
     should be blurred.  This program requires the OpenGL convolution
     extension.

An example TIFF file "face.tif" (a picture of me) is included as an
example TIFF file to play with.

- Mark Kilgard
  April 14, 1997
