Anti-Aliasing aside, you could take the image inside Java and process
it. Essentially take every pixel that is a specific color (your
background color) and make those pixels transparent. (I even have some
code lost somewhere that does that)
- John Wright
Starfire Research
"Yazel, David J." wrote:
>
> Ah, then in effect you are drawing an image onto your canvas, even though
> that image is a the result of taking a snapshot of a 3d object. Next
> question... are you drawing your image to a AWT canvas, using a graphics
> context, or are you puttting your image into a Java3d scene? Eaither way,
> you will need to create an alpha channel in your image. There is no
> "transparent" image really. When you rendered to the offscreen buffer, you
> effectively made an image, with every pixel filled in. You now need a mask
> to be able to draw this without a background. As far as I know, and I could
> be wrong, you cannot render to an offscreen buffer and have it set the alpha
> channel automatically, although that would be nice. And you can't really
> pick a background color for your mask because the scene will be anti aliased
> against the background color. Perhaps there is a trick someone else knows
> about.
>
> > ----------
> > From: Tater Read[SMTP:[EMAIL PROTECTED]]
> > Reply To: Discussion list for Java 3D API
> > Sent: Tuesday, September 05, 2000 12:30 PM
> > To: [EMAIL PROTECTED]
> > Subject: Re: [JAVA3D] Making background Transparent
> >
> > I'm using a color background. The 3D objects themselves are not being
> > occluded, it's the underlying vector graphics that are being occluded.
> > That
> > is, I'm rendering the 3D scene to an off-screen buffer, copying the image,
> > then drawing it to a graphics context. So ideally, the background color
> > should be transparent.
> >
> > Cheers,
> >
> > Tater
> >
> >
> >
> > The background should not be occluding your objects. Are you using
> > background geometry, image or color?
> >
> > >
> > > Hi Dave,
> > >
> > > I suppose at some point I would like to add transparency to the 3D
> > objects
> > > in the scene but for now I am just adding opaque 3D objects with images
> > > and/or vector graphics in the background. By the way, I noticed that
> > the
> > > ImageComponent supports an RGBA format, how do you set the Background to
> > > be
> > > transparent? From the constructor it looks like it only takes RGB
> > values.
> > >
> > > Cheers,
> > >
> > > Tater
> > >
> > >
> > >
> > >
> > > I am not sure what you mean. If you mean can you draw a transparent
> > > image,
> > > then yes you can use alpha blending to great effect. You can set the
> > > transparency attributes on the polygon to totally transparent then
> > texture
> > > it with BLEND and with a RGBA loaded image (PNG works very well).
> > >
> > > Dave Yazel
> > >
> > >
> > > > Hello,
> > > >
> > > > I'm creating a simple 3D scene that I want to draw onto a canvas with
> > > > other
> > > > graphics objects. Unfortunately, the background ends up being a black
> > > > rectangle on top of the graphics. Is there a way of setting the
> > > > background
> > > > to be transparent?
> > > >
> > > > Cheers,
> > > >
> > > > Tater
> > > >
> > > >
> > > > Tater Read
> > > > Research & Development
> > > > Improv Technologies
> > > > 535 Eigth Avenue
> > > > New York, NY 10018
> > > > (212) 725-4590
> > > >
> > > >
> > >
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