Method addSubtree

CesiumGeometry/src/QuadtreeAvailability.cpp:211–322

}

bool QuadtreeAvailability::addSubtree(
    const QuadtreeTileID& tileID,
    AvailabilitySubtree&& newSubtree) noexcept {

  if (tileID.level == 0) {
    if (this->_pRoot) {
      // The root subtree already exists.
      return false;
    } else {
      // Set the root subtree.
      this->_pRoot = std::make_unique<AvailabilityNode>();
      this->_pRoot->setLoadedSubtree(
          std::move(newSubtree),
          this->_maximumChildrenSubtrees);
      return true;
    }
  }

  if (!this->_pRoot) {
    return false;
  }

  AvailabilityNode* pNode = this->_pRoot.get();
  uint32_t level = 0;

  while (pNode && pNode->subtree && tileID.level > level) {
    AvailabilitySubtree& subtree = *pNode->subtree;

    AvailabilityAccessor subtreeAvailabilityAccessor(
        subtree.subtreeAvailability,
        subtree);

    uint32_t levelsLeft = tileID.level - level;

    // The given subtree to add must fall exactly at the end of an existing
    // subtree.
    if (levelsLeft < this->_subtreeLevels) {
      return false;
    }

    // TODO: consolidate duplicated code here...

    uint32_t subtreeRelativeMask = ~(0xFFFFFFFF << levelsLeft);
    uint32_t levelsLeftAfterChildren = levelsLeft - this->_subtreeLevels;
    uint32_t childSubtreeMortonIndex = getMortonIndex(
        (tileID.x & subtreeRelativeMask) >> levelsLeftAfterChildren,
        (tileID.y & subtreeRelativeMask) >> levelsLeftAfterChildren);

    // Check if the needed child subtree exists.
    bool childSubtreeAvailable = false;
    uint32_t childSubtreeIndex = 0;

    if (subtreeAvailabilityAccessor.isConstant()) {
      childSubtreeAvailable = subtreeAvailabilityAccessor.getConstant();
      childSubtreeIndex = childSubtreeMortonIndex;
    } else if (subtreeAvailabilityAccessor.isBufferView()) {
      uint32_t byteIndex = childSubtreeMortonIndex >> 3;
      uint8_t bitIndex = static_cast<uint8_t>(childSubtreeMortonIndex & 7);