void update(float tpf, TempVars vars) {
        if (animation == null)
            return;

        if (blendFrom != null && blendAmount != 1.0f) {
            // The blendFrom anim is set, the actual animation
            // playing will be set
//            blendFrom.setTime(timeBlendFrom, 1f, control, this, vars);
            blendFrom.setTime(timeBlendFrom, 1f - blendAmount, control, this, vars);

            timeBlendFrom += tpf * speedBlendFrom;
            timeBlendFrom = AnimationUtils.clampWrapTime(timeBlendFrom,
                    blendFrom.getLength(),
                    loopModeBlendFrom);
            if (timeBlendFrom < 0) {
                timeBlendFrom = -timeBlendFrom;
                speedBlendFrom = -speedBlendFrom;
            }

            blendAmount += tpf * blendRate;
            if (blendAmount > 1f) {
                blendAmount = 1f;
                blendFrom = null;
            }
        }

        animation.setTime(time, blendAmount, control, this, vars);
        time += tpf * speed;
        if (animation.getLength() > 0) {
            if (!notified && (time >= animation.getLength() || time < 0)) {
                if (loopMode == LoopMode.DontLoop) {
                    // Note that this flag has to be set before calling the notify,
                    // since the notify may start a new animation and then unset
                    // the flag.
                    notified = true;
                }
                control.notifyAnimCycleDone(this, animation.getName());
            }
        }
        time = AnimationUtils.clampWrapTime(time, animation.getLength(), loopMode);
        if (time < 0) {
            // Negative time indicates that speed should be inverted
            // (for cycle loop mode only)
            time = -time;
            speed = -speed;
        }
    }
Add bones to be influenced by this animation channel, starting
from the given bone and going toward its children.

@param bone the Bone to use as a starting point
jme3-core/src/main/java/com/jme3/animation/AnimChannel.java