function getKeyframeIndexPrev(targetKeyframe, keyframeNodes) {
  const keyframeIndex = findKeyframeIndex(targetKeyframe, keyframeNodes);
  return keyframeIndex < 0
    ? CesiumMath.clamp(~keyframeIndex - 1, 0, keyframeNodes.length - 1)
    : keyframeIndex;
}
Computes the most suitable keyframes for rendering, balancing between temporal and visual quality.

@param {number} keyframeLocation