[Plib-users] Translucency solved!

[Martin H. <how...@os...>]

OK, I did a search for "plib" and "transparent" in Google and got the PUI
programmer's guide (which I hadn't read: because I don't use it).  In there
is a heading "Transparent GUI's".  It suggests:

    * pick a default colour with an alpha component of about 0.4f.
    * call glEnable(GL_BLEND) and set up an appropriate blend function;
      the author suggests glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
      and using glAlphaFunc(GL_GREATER, 0.1f) -- the latter translates into
      using state->setAlphaClamp(0.1f).

So, in the *global* set-up portion of my program, I called glBlendFunc() and
whadd'ya know: I now have a beautiful semi-transparent plane.

In conclusion then: glBlendFunc() is *not* set up to some reasonable default
by PLIB -- at least not if you want to have transparent objects in your
scene.  Putting the glBlendFunc() in a preDraw() or postDraw() callback is
*not* sufficient to get the transparency to render correctly.  It needs to
go into the global set-up just after the call to ssgInit().

Finally, I'd like to extend a warm "thank you" to all who helped and to
those who developed and continue to develop PLIB.

M.

-- 
Martin Howard                    |
Visiting Scholar, CSEL, OSU      | The New Economy: Creating difficulties
email: how...@os...        | to sell solutions.
www: http://mvhoward.i.am/       +----------------------------------------