Lee,
You can at least experiment with the implementation using our Applet here:
http://www.tornadolabs.com/News/Alpha_Applet/alpha_applet.html
As Microsoft used to be found of quoting, "Functions as implemented." ;-)
Sincerely,
Daniel Selman
-----Original Message-----
From: Discussion list for Java 3D API
[mailto:[EMAIL PROTECTED]]On Behalf Of J. Lee Dixon
Sent: Wednesday, February 07, 2001 7:09 AM
To: [EMAIL PROTECTED]
Subject: Re: Alpha: Setting mode does not disable use of increasi
ngAlphaDuration
Okay, how about a quote from the Java3D tutorial then?
"The mode specification overrides the duration parameter settings. For
example, when the mode is INCREASING_ENABLE, the
DecreasingAlphaDuration, DecreasingAlphaRampDuration, and
AlphaAtZeroDuration parameters are ignored. While any waveform may be
specified by setting the duration of unwanted phases to zero, the proper
specification of the mode increases the efficiency of the Alpha object."
According to the code snippet from Kelvin, it is obviously not coded
that way. The tutorial even says "don't set it to zero", you should set
the mode instead.
-Lee
> -----Original Message-----
> From: John Wright [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, February 07, 2001 8:41 AM
> To: [EMAIL PROTECTED]
> Subject: Re: [JAVA3D] Alpha: Setting mode does not disable use of
> increasingAlphaDuration
>
>
> Lee,
>
> I have to say that my understanding of this was the same as Kelvin
> explained it. That is the way I would expect it to work. It is
> similiar to in music having an "attack" "sustain" "decay".
>
> - John Wright
> Starfire Research
>
> "J. Lee Dixon" wrote:
> >
> > Kelvin,
> > This doesn't make sense. The JavaDoc for "Alpha" says:
> >
> > mode -- This can be set to INCREASING_ENABLE,
> DECREASING_ENABLE, or the
> > Or'ed value of the two. INCREASING_ENABLE activates the
> increasing Alpha
> > parameters listed below; DECREASING_ENABLE activates the decreasing
> > Alpha parameters listed below.
> >
> > This DEFINITELY makes it sound that if I use
> "DECREASING_ENABLE", that
> > the 'increasing Alpha parameters' will be inactive. I think the
> > computation of "stopTime" is wrong.
> >
> > This also doesn't make sense because I was able to make the Alpha
> > transition from 1 to 0 several times during a single loop.
> I am sure
> > that this is not the intended behavior of Alpha.
> >
> > Are the any developers in "Java3D land" that expect this type of
> > behavior, and would be affected adversely if it was changed?
> >
> > -Lee
> >
> > > -----Original Message-----
> > > From: Kelvin Chung [mailto:[EMAIL PROTECTED]]
> > > Sent: Tuesday, February 06, 2001 4:51 PM
> > > To: [EMAIL PROTECTED]
> > > Subject: Re: [JAVA3D] Alpha: Setting mode does not disable use of
> > > increasingAlphaDurati on
> > >
> > >
> > > Hi Joel,
> > >
> > > The stopTime of Alpha is equal to:
> > >
> > > stopTime = triggerTime + phaseDelayDuration +
> > > loopCount* (increasingAlphaDuration+
> > > alphaAtOneDuration+
> > > decreasingAlphaDuration+
> > > alphaAtZeroDuration);
> > >
> > > When alpha is initialize as
> > > Alpha a = new Alpha(1, 2000);
> > > the increasingAlphaDuration is set to 2 sec
> > > the decreasingAlphaDuration is set to 0 sec
> > > stop time is therefore 2 sec.
> > >
> > > After
> > > a.setDecreasingAlphaDuration(1500);
> > > a.setMode(Alpha.DECREASING_ENABLE);
> > > a.setStartTime(System.currentTimeMillis());
> > >
> > > the decreasingAlphaDuration is 1.5 sec
> > > the above functions did not change increasingAlphaDuration
> > > which remains 2 sec. (The spec. did not mention
> > > that this will reset increasingAlphaDuration to 0)
> > > Thus stop time according to the formula is 3.5 sec
> > > which is correct behavior.
> > >
> > > That's why if we later set
> > > a.setIncreasingAlphaDuration(0);
> > > the stop time becomes 1.5 sec.
> > >
> > > Thanks.
> > >
> > > - Kelvin
> > > -----------
> > > Java 3D Team
> > > Sun Microsystems Inc.
> > >
> > >
> > > >MIME-Version: 1.0
> > > >Date: Tue, 6 Feb 2001 14:37:13 -0500
> > > >From: "J. Lee Dixon" <[EMAIL PROTECTED]>
> > > >Subject: [JAVA3D] Alpha: Setting mode does not disable use of
> > > increasingAlphaDurati on
> > > >Comments: To: "Java3DBugReporting (E-mail)" <[EMAIL PROTECTED]>
> > > >To: [EMAIL PROTECTED]
> > > >
> > > >JDK 1.3, Java3D v1.2.1Beta1
> > > >
> > > >In my code, I use the same Alpha for doing a simple 2 second
> > > up-ramp (0
> > > >to 1)...
> > > > Alpha a = new Alpha(1, 2000);
> > > >This works fine.
> > > >
> > > >... then later use the same object to do a simple 1.5sec
> > > down ramp (1 to
> > > >0)
> > > > a.setDecreasingAlphaDuration(1500);
> > > > a.setMode(Alpha.DECREASING_ENABLE);
> > > > a.setStartTime(System.currentTimeMillis());
> > > >
> > > >This should disable the "increasing" parameters, but it
> doesn't. The
> > > >alpha lasts for 3.5 seconds, going from 1 to 0 every 1.5
> seconds and
> > > >jumping to 0 after 3.5 seconds. I've included a
> snapshot of a graph
> > > >showing the trend, and the code used to generate the bug data.
> > > >
> > > > WORKAROUND:
> > > > a.setIncreasingAlphaDuration(0);
> > > >
> > > > <<graph.jpg>> <<AlphaTest.java>>
> > > >
> > > >J. Lee Dixon
> > > >SAIC - Celebration, FL
> > > >407-566-1438
> > > >[EMAIL PROTECTED] AOL: LeeOrlando
> > > >
> > >
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> message "help".
> > >
> >
> >
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