Getting this ready for Gawain treatment.
Removed setlinestyle(0) -- solid lines are the default, hope this isn't
really needed.
Eliminated redundant math.
Arithmetic is still double precision, passed to OpenGL as single
precision. Even though it said GL_DOUBLE before, values were converted
to GL_FLOAT internally.
Use C99-isms for declaring variables close to where they're used.
Minor whitespace tweaks.
dfbc51f764