HP PTM Viewer Help
	Polynomial Texture Map (PTM) Viewer. Copyright Hewlett-Packard Company 2001. All rights reserved. http://www.hpl.hp.com/ptm/ Instructions reproduced courtesy Hewlett Packard.
		This program is a browser for Polynomial Texture Maps (PTM's). The left window gives a spatial view of such texture maps, the right window provides a view of the reflectance function for a paticular pixel that has been selected in the left window. This reflectance function is internally represented as a biquadradic polynomial, and represents the surface color, usually as a function of parameterized light direction. Hence, the right window displays the color of a pixel as the light direction varies. Left-clicking in the left window selects the pixel, left-clicking on the right window sets the light direction. The right button is used to access the menu. The image can be modified by adding specular enhancement or diffuse gain. These modes must be enabled in the menu first (right mouse click). The arrow keys and the +,- keys can be used for panning and zooming.
		The middle button is used for selecting regions of the spatial image. This has two uses, first it selects the region of the image for fast updates during changes to ptm parameters. Use shift-left button if you have no middle button. Second, the selected region is used when writing out a cropped ptm file. It will be necessary to type the output file name in the text window when outputing files, so make sure this is visible. If available the original source images can be accessed by selecting them in the ptm window. The keys 'c' and 'p' can be used to construct paletized PTM's from LRGB format ptms. The 'a' key enables the autopilot. The number keys 1-9 allow additional lights to be enabled and disabled.
		If the viewer runs excessively slow with visible refreshes on your system, please try running the viewer from the command line with a -d option. E.g. "PTMViewer -d tablet1.ptm". You should disable page flipping or fast buffer swaps under your video card's OpenGL settings if possible.
		If this does not result in an acceptable speed, you may try reducing the area that is interactively updated by selecting a region in the spatial window by dragging with the middle mouse button.
		The viewer's display options are selected from a Java applet window activated by clicking the right mouse button. The direction from which the image is illuminated is determined by clicking and dragging the left mouse button.
	Additional notes:
	The JPEG decoding section of this software is based on the work of the Independent JPEG Group.
	The objects in the tablet1.ptm and ushabti.ptm datasets are artifacts belonging to the Archaeological Research Collection of the University of Southern California.