The following is an excerpt from the next chapter (5) of the Java 3D
API Tutorial. This particular section addresses the smoothing
of the alpha waveform only.
Chapter 5, titled Animation, will explain the Alpha,
interpolator, BillboardBehavior, LOD, and Morph classes.
Attached is an example of Alpha smoothing.
Chapter 5 may be published before the end of July.
I hope this helps,
Dennis
Smoothing of the Alpha Waveform
In addition to the duration of the four phases, the programmer
can specify a ramp duration for the increasing alpha and decreasing
alpha phases. During the ramp duration, the alpha value changes
gradually. In the case of motion interpolators, it will appear
as though the visual object is accelerating and decelerating in
a more natural, real world, manner.
The ramp duration value is used for both the beginning and ending
portions of the phase and therefore the ramp duration is limited
to half of the duration of the phase. Figure 5-6 shows an Alpha
waveform with both IncreasingAlphaRampDuration and a
DecreasingAlphaRampDuration. Note that the alpha value changes
linearly between the two ramp periods.
An example program, AlphaApp.java, demonstrates the effect
of an IncreasingAlphaRampDuration on an Alpha waveform. In
this program there are three car visual objects. The three
cars start at the same time from the same x coordinate and
travel parallel. The upper car has no ramp (ramp duration = 0),
the bottom car has maximum ramp duration (half of the duration
of the increasing or decreasing alpha duration), and the middle
car has half the maximum ramp duration (one quarter of the
duration of the increasing or decreasing alpha duration).
Each car takes two seconds to cross the view.
Vladimir Olenin wrote:
>
> Hi,
>
> Let say that ViewPlatfrom is a car and i want to move it in accordance
> with physics laws. This means that in the first place i need to specify
> "ease-in"/"ease-out" behavior for acceleration/deceleration. It is said
> in Java3D official documentation that for these purposes Interpolators
> can be used (in section 9.6.2 - Acceleration of Alpha). It is said there
> what Alpha parameters resposible for what, but, alas, no examples.
>
> This is quite a tough topic, so, please, if anyone out here has some
> examples of using Interpolators or knows the sequence in which they
> should be created/used/terminated, i would very appreciate any
> information. Thank u!
>
> vladimir
> --
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--
-----
Dennis J Bouvier
Find the Java 3D Tutorial "Getting Started with the Java 3D API" at
http://sun.com/desktop/java3d/collateral
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