defrasterPort: OpenGL & X versions of IrisGL defrasterfont

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This directory contains example codes which will allow you to use the bitmaps defined for irisGL defrasterfont() in an openGL environment or X environment.

defrasterfont() is an IRIS GL call that lets you customize raster fonts. Typically, you customize raster fonts in order to define special marker symbols that you would use either for annotation or in user interfaces. After you define the font by using defrasterfont(), you render it using charstr().

glBitmap() is the OpenGL call for rendering bitmaps. Bitmap data is always stored in 8-bit chunks that are defined from left to right and from bottom to top.

The bitmap format that X uses differs slightly: Each byte of the bitmap data is divided into two 4-bit segments, left and right. The defX.c utility first reverses, then swaps the segments; for example, it converts 00011100 to 00111000.

If you are porting an IRIS GL application to OpenGL and you want to take advantage of your existing defrasterfont() bitmap data, use the following file and utilities:

defi.c:  sample utility that shows how you use defrasterfont in IRIS GL.

defo.c:  converts and renders to OpenGL window -- use the 
         routine in this utility to render IRIS GL bitmap data in OpenGL.

defx.c:  converts and renders to X window -- use the 
         routine in this utility to render IRIS GL bitmap data in X.

The test bitmaps are included in the .c files.

Yusuf Attarwala December, 1994