Blending

[Greg Bennett]

I am trying to use some of the ideas of Ch6 Blending, etc. of the OpenGL
Programming Guide. Specifically I am interested in the use of the A
attribute of glColor for erasing points, lines, etc..

The beginning of Ch6 talks about blending and its first example
emphasizes the need to call glEnable and glBlendFunc before actually
drawing anything, although I can get somewhere without these.

I have found the definitions of the cl-opengl versions in 
funcs-gl-gles1-gles2.lisp (in the gl subdirectory of cl-opengl), so
I assume they are callable. I'm stuck one the appropriate arguments.

P230 0f the Guide, Example 6-1 starts with
   glColorClear(1.0, 1.0, 1.0, 0.0);
   glBlendFunc(GL_ONE, GL_ONE);
   glEnable(GL_BLEND);

and GL_ONE is defined on P228 as (1,1,1).

I would be grateful for information about the calling sequences of the
above 3 lines in cl-opengl. Perhaps there are examples/sources I should
be aware of which would save me posting to the list.

Thanks for any and all assistance.
Cheers /Greg Bennett