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Easy Polygonal Text Rendering
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* glyph.c
glyph.c provides an efficient, portable means of rendering text using
OpenGL.
It renders text as polygons, since polygonal text scales both up and
down better than texture-mapped, line-stroke, or bitmap text. Each
glyph is represented using only a few triangles, specified using
triangle strips. In most cases, each vertex is touched only once.
Despite the low polygon count, text is extremely legible at most any
size.
This code does not rely upon GLX, WGL, Freetype, or any other external
library, so it can be easily included in code for any platform. It
has been tested under Win2K, Linux and IRIX.
The font description requires less than 2KB of memory and is specified
in less than 500 lines of C code. It is linked directly with the
application, so no external file loading is necessary.
Glyphs are drawn mono-spaced in a 1x1 unit square in the Z plane.
Text may be transformed normally. In the opinion of the author, it
looks best when scaled to a 1:2 aspect ratio.
Using the default renderer, draw_glyph(), a translation one unit to
the right is applied after each glyph is drawn. This allows a string
to be rendered as a sequence of calls to draw_glyph().
Text is rendered using the current material properties. If it is to
be correctly lit, set the current normal to [0 0 1] before calling the
renderer.
draw_glyph() uses OpenGL immediate mode, but it may be called during
the creation of a display list. Only slightly more effort is required
to create vertex arrays.
Representations of all 128 ASCII characters are defined. Non-printing
characters appear as a "no glyph" box.
* test.c
test.c is a simple GLUT-based program that renders all 128 characters.
Resize the window to see how the font looks at different sizes and
aspect ratios. For very small text, it is recommended that polygon
smoothing or full-screen anti-aliasing be enabled.
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The zip file viewer built into the Developer Toolbox made use
of the zlib library, as well as the zlibdll source additions.
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