Re: [PyOpenGL-Users] Aliasing changes when I have a white background

[Rick M. <rpm...@gm...>]

This is indeed what it looks like, which is why I think I'm doing
something wrong. I thought I was drawing the image on white, but
perhaps I'm not doing what I think I'm doing. Could double buffering
be messing me up here?

The basic way I'm updating my screen is:

        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)

        #anti-aliasing code
        glEnable(GL_BLEND)
        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
        glHint(GL_LINE_SMOOTH_HINT, GL_DONT_CARE)

        glPushMatrix()
        glCallList(self.dlist)
        glPopMatrix()

        self.SwapBuffers()

However, I only set the color when I setup the canvas, so maybe I'm
not updating it in the second buffer. Does anyone have any thoughts on
this?

On 8/11/07, vwf <vw...@vu...> wrote:
> On Fri, Aug 10, 2007 at 02:38:21PM -0600, Rick Muller wrote:
> > http://farm2.static.flickr.com/1037/1074160261_a963714943_o.png
> > If this isn't publication quality, it's close enough that I don't care
> > about the difference.
> > However, when I draw a molecule with a white background, the aliasing looks bad:
> > http://farm2.static.flickr.com/1314/1074160459_5baa206cc4_o.png
> > I'm not a real OpenGL expert, so I'm probably doing something wrong.
>
> I am not an OpenGL anti-aliasing expert either, but did you really draw
> the second image on white? It looks like you drew it on black, and
> placed it on a white background afterwards.
>
>


-- 
Rick Muller
rpm...@gm...