The loopCount parameter (9) allows Alpha functions to be repeated (a fixed number of times or infinitely) by joining Alpha functions end to end. Note that the Alpha value varies linearly between the quadratic sections. These quadratic sections help to smooth the transition from 0 to 1 ( increasing alpha) or 1 to 0 ( decreasing alpha). The values of increasing alpha ramp (4) and decreasing alpha ramp (7) define symmetrical acceleration and deceleration of the Alpha value at the beginning and end of the phase. The increasing alpha phase (3) is composed of three potential sections, as is the decreasing alpha phase (6). Nine parameters can be used to create a customized Alpha function are listed there.ДЇigure 12.1 The phases of the Alpha class: triggerTime (1), phase delay (2), increasing alpha (3), increasing alpha ramp (4), at one (5), decreasing alpha (6), decreasing alpha ramp (7), at zero (8), and loopCount (9) The Alpha class uses a parameterized function to convert time values to alpha values between 0 and 1.ДЇigure 12.1 illustrates the basic shape of the functions that can be created using the Alpha class. Table 12.1 Coordinate calculation using Alpha Time (seconds) The PositionInterpolator can then use the Alpha object to create the desired z coordinate (table 12.1). To achieve the desired result, an Alpha object must be created that returns 0 at 0 seconds and 1 at 10 seconds.

The alpha value can then be used by the Interpolator to produce the desired interpolation between specified end states.ДЇor example, a PositionInterpolator might be used to move an object between position (0,0,0) and (0,0,5) in 10 seconds. The Alpha class defines a function that converts the current time (in milliseconds) to a value between 0 and 1 ( alpha value). The Alpha class is described in section 12.2.ДЄ good understanding of the Alpha class is key to using all the Interpolator behaviors. The Alpha class is used to convert the current time to a value between 0 and 1-this value is then used by the Interpolator to perform its specific action.

Transparency-Linearly between transparency valuesДЄll the Interpolation classes require an Alpha object.

Spline path-Position along a specified spline path.

Switch value-Toggle Switch NodeвЂ™s visible child based on time.

Color-Linearly between diffuse material colors.

Interpolator behaviors can be used to interpolate an objectвЂ™s: These behaviors are important for many animation and visualization applications and are covered in detail in this section. Java 3D includes a rich set of behaviors for interpolating an object between states. This chapter introduces the Interpolator classes and the Alpha class, which is used to control the speed of interpolation. The behaviors derived from Interpolator allow an objectвЂ™s current state to be interpolated between a set of defined states as a function of time. The Interpolator class defines the functionality for an important and powerful set of behaviors that deserve extra mention. Java 3D Programming.Chapter 12 CHAPTER 12 Using Interpolator

Java 3d animation source code