Well to be honest the last time I explained to someone what we are doing
they called it a "hack" and "useless", so I generally don't give that as an
option. It seemed clear to me that Corysia is looking for *true* overlay,
allowing her to alpha blend text and images into the screen, and place
non-rectangular objects on the screen. A HUD requires that capability.
What we are doing is hovering JWindow's over the canvas3d and placing our
interface objects in the JWindows. JWindows are nice because they are
borderless, allowing us to control their appearance to match the "look" of
our application. But they are square, and they cannot be blended into the
scene, hence they are not a true overlay.
Dave Yazel
-----Original Message-----
From: John Wright [mailto:[EMAIL PROTECTED]]
Sent: Monday, April 02, 2001 6:00 PM
To: [EMAIL PROTECTED]
Subject: Re: [JAVA3D] Overlay example?
Dave,
I'm surprised at this response from you. Your screenshots have included
some nice overlays (including what looks like a chat window). Are you
saying that you are painting these as textures and placing them in your
3D scene???
- John Wright
Starfire Research
"Yazel, David J." wrote:
>
> To my knowledge the only way to do this is to have transformed textured
> coplanar geometry parallel to the image plate, and update its transform
> every frame to remain synchronized with the view. This works great for
> untextured geometries or for textures that change infrequently.
> Unfortunatly, text is the biggest problem. First of all you end up
creating
> very large textures to show your text if it spans any kind of space at
all.
> Secondly, you have to use the video texture technique (y-up and
> by-reference) and your texture gets sent to the card over and over again.
>
> If there is a way to quickly write to the back-buffer before swap I have
not
> seen it. In OpenGL this is done very easily, but in Java3d this is quite
> slow.
>
> If you are interested in some example code to write synchronized image
> plates I am attaching a java file.
>
> Dave Yazel
>
> -----Original Message-----
> From: Corysia Taware [mailto:[EMAIL PROTECTED]]
> Sent: Monday, April 02, 2001 2:43 PM
> To: [EMAIL PROTECTED]
> Subject: Re: [JAVA3D] Overlay example?
>
> Attached is a screenshot from a small OpenGL game called Orbit. This
> screenshot illustrates what I'm trying to accomplish. The jpg I made
looked
> horrible, so I chose the png format. It should be viewable in IE or
> Netscape. The text label for Saturn is the same size as the text label
for
> the moon. Also, the frames per second counter in the lower left corner
> aren't associated with any object in the scene. The text is written to
the
> raster with glRasterPos2*(). The result is the text is written directly
to
> the viewplate.
>
> I spent this weekend trying to figure out how this can be done in Java3D.
I
> spent quite a lot of time searching on the net for examples, but only
found
> one that came close. The game Tron3D in Java3D uses an extended Canvas3D
> object to overload postSwap(). In there, the author writes directly to
the
> canvas if a String has been populated. This seems to work fine for static
> text, but doesn't clear properly if you change it. I tried overloading
> postRender() instead, but I had the same effect. Drawing a 3, then a 6
gave
> you something that looks closer to an 8.
>
> The only other thing I can think of doing is floating some Java2D text
> immediately in front of the View. This doesn't seem to me to be the
"right"
> way to do it. It certainly isn't in OpenGL. I'm also not sure how
> expensive Text2D.setString() is.
>
> I also looked at Jon Barrilleaux's examples from his book. Unfortunately,
> since I don't have the book and my local bookstore didn't have it in
stock,
> I got lost in his library pretty quickly. Off to Amazon.com... But,
there
> are also some strange effects that happen when the window is resized --
the
> items seem to need to figure out where they're supposed to be and take a
few
> frames to get repositioned.
>
> If someone can point me in the right direction for this, I'd really
> appreciate it.
>
> ------------------------------------------------------------------------
> Name: TestConsole.java
> TestConsole.java Type: JAVA File
(application/x-unknown-content-type-javaFile)
> Encoding: quoted-printable
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