The alpha NodeComponent object provides common methods for
converting a time value into an alpha value (a value in the range 0
to 1). The Alpha object is effectively a function of time that
generates alpha values in the range [0,1] when sampled: f(t) =
[0,1]. A primary use of the Alpha object is to provide alpha
values for Interpolator behaviors. The function f(t) and the
characteristics of the Alpha object are determined by
user-definable parameters:
loopCount -- This is the number of times to run this
Alpha; a value of -1 specifies that the Alpha loops
indefinitely.
triggerTime -- This is the time in milliseconds since
the start time that this object first triggers. If (startTime +
triggerTime >= currentTime) then the Alpha object starts running.
phaseDelayDuration -- This is an additional number of
milliseconds to wait after triggerTime before actually starting
this Alpha.
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.
Increasing Alpha parameters:
increasingAlphaDuration -- This is the period of time
during which Alpha goes from zero to one.
increasingAlphaRampDuration -- This is the period of
time during which the Alpha step size increases at the beginning of
the increasingAlphaDuration and, correspondingly, decreases at the
end of the increasingAlphaDuration. This parameter is clamped to
half of increasingAlphaDuration. When this parameter is non-zero,
one gets constant acceleration while it is in effect; constant
positive acceleration at the beginning of the ramp and constant
negative acceleration at the end of the ramp. If this parameter is
zero, then the effective velocity of the Alpha value is constant
and the acceleration is zero (ie, a linearly increasing alpha
ramp).
alphaAtOneDuration -- This is the period of time that
Alpha stays at one.
Decreasing Alpha parameters:
decreasingAlphaDuration -- This is the period of time
during which Alpha goes from one to zero.
decreasingAlphaRampDuration -- This is the period of
time during which the Alpha step size increases at the beginning of
the decreasingAlphaDuration and, correspondingly, decreases at the
end of the decreasingAlphaDuration. This parameter is clamped to
half of decreasingAlphaDuration. When this parameter is non-zero,
one gets constant acceleration while it is in effect; constant
positive acceleration at the beginning of the ramp and constant
negative acceleration at the end of the ramp. If this parameter is
zero, the effective velocity of the Alpha value is constant and the
acceleration is zero (i.e., a linearly-decreasing alpha ramp).
alphaAtZeroDuration -- This is the period of time that
Alpha stays at zero.
Increasing Alpha parameters:loopCount-- This is the number of times to run this Alpha; a value of -1 specifies that the Alpha loops indefinitely.triggerTime-- This is the time in milliseconds since the start time that this object first triggers. If (startTime + triggerTime >= currentTime) then the Alpha object starts running.phaseDelayDuration-- This is an additional number of milliseconds to wait after triggerTime before actually starting this Alpha.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.
Decreasing Alpha parameters:increasingAlphaDuration-- This is the period of time during which Alpha goes from zero to one.increasingAlphaRampDuration-- This is the period of time during which the Alpha step size increases at the beginning of the increasingAlphaDuration and, correspondingly, decreases at the end of the increasingAlphaDuration. This parameter is clamped to half of increasingAlphaDuration. When this parameter is non-zero, one gets constant acceleration while it is in effect; constant positive acceleration at the beginning of the ramp and constant negative acceleration at the end of the ramp. If this parameter is zero, then the effective velocity of the Alpha value is constant and the acceleration is zero (ie, a linearly increasing alpha ramp).alphaAtOneDuration-- This is the period of time that Alpha stays at one.decreasingAlphaDuration-- This is the period of time during which Alpha goes from one to zero.decreasingAlphaRampDuration-- This is the period of time during which the Alpha step size increases at the beginning of the decreasingAlphaDuration and, correspondingly, decreases at the end of the decreasingAlphaDuration. This parameter is clamped to half of decreasingAlphaDuration. When this parameter is non-zero, one gets constant acceleration while it is in effect; constant positive acceleration at the beginning of the ramp and constant negative acceleration at the end of the ramp. If this parameter is zero, the effective velocity of the Alpha value is constant and the acceleration is zero (i.e., a linearly-decreasing alpha ramp).alphaAtZeroDuration-- This is the period of time that Alpha stays at zero.