初始提交: UE5.3项目基础框架

Plugins/CesiumForUnreal/Source/ThirdParty/include/CesiumGeometry/QuadtreeRectangleAvailability.h

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+#pragma once
+
+#include "Library.h"
+#include "QuadtreeTileRectangularRange.h"
+#include "QuadtreeTilingScheme.h"
+#include "Rectangle.h"
+
+#include <glm/vec2.hpp>
+
+#include <memory>
+#include <vector>
+
+namespace CesiumGeometry {
+
+/**
+ * @brief Manages information about the availability of tiles in a quadtree.
+ */
+class CESIUMGEOMETRY_API QuadtreeRectangleAvailability final {
+public:
+  /**
+   * @brief Creates a new instance.
+   *
+   * @param tilingScheme The {@link QuadtreeTilingScheme}.
+   * @param maximumLevel The maximum level (height of the tree) for which
+   * the availability should be tracked.
+   */
+  QuadtreeRectangleAvailability(
+      const QuadtreeTilingScheme& tilingScheme,
+      uint32_t maximumLevel) noexcept;
+
+  /**
+   * @brief Adds the specified range to the set of available tiles.
+   *
+   * @param range The {@link QuadtreeTileRectangularRange} that describes
+   * the range of available tiles.
+   */
+  void
+  addAvailableTileRange(const QuadtreeTileRectangularRange& range) noexcept;
+
+  /**
+   * @brief Computes the maximum level for the given 2D position.
+   *
+   * This will compute the maximum level of any available tile for
+   * the given position. The position refers to the 2D space that
+   * is covered by the nodes of the quadtree.
+   *
+   * @param position The 2D position.
+   * @return The maximum level at the given position. This may be 0 if
+   * the position is not covered by the quadtree at all.
+   */
+  uint32_t
+  computeMaximumLevelAtPosition(const glm::dvec2& position) const noexcept;
+
+  /**
+   * @brief Returns whether a certain tile is available.
+   *
+   * This checks the availability of the tile that is described by the
+   * given {@link QuadtreeTileID}, which consists of the level and
+   * the x- and y- coordinates of the queried tile.
+   *
+   * @param id The quadtree tile ID.
+   * @returns The {@link CesiumGeometry::TileAvailabilityFlags} for this tile,
+   * encoded into an uint8_t.
+   */
+  uint8_t isTileAvailable(const QuadtreeTileID& id) const noexcept;
+
+private:
+  struct RectangleWithLevel {
+    uint32_t level;
+    Rectangle rectangle;
+  };
+
+  struct QuadtreeNode {
+    QuadtreeNode(
+        const QuadtreeTileID& id_,
+        const Rectangle& extent_,
+        QuadtreeNode* pParent_) noexcept
+        : id(id_),
+          extent(extent_),
+          pParent(pParent_),
+          ll(),
+          lr(),
+          ul(),
+          ur(),
+          rectangles() {}
+
+    QuadtreeTileID id;
+
+    CesiumGeometry::Rectangle extent;
+
+    QuadtreeNode* pParent;
+    std::unique_ptr<QuadtreeNode> ll;
+    std::unique_ptr<QuadtreeNode> lr;
+    std::unique_ptr<QuadtreeNode> ul;
+    std::unique_ptr<QuadtreeNode> ur;
+
+    std::vector<RectangleWithLevel> rectangles;
+  };
+
+  QuadtreeTilingScheme _tilingScheme;
+  uint32_t _maximumLevel;
+  std::vector<std::unique_ptr<QuadtreeNode>> _rootNodes;
+
+  static void putRectangleInQuadtree(
+      const QuadtreeTilingScheme& tilingScheme,
+      uint32_t maximumLevel,
+      QuadtreeRectangleAvailability::QuadtreeNode& node,
+      const QuadtreeRectangleAvailability::RectangleWithLevel&
+          rectangle) noexcept;
+  static bool rectangleLevelComparator(
+      const QuadtreeRectangleAvailability::RectangleWithLevel& a,
+      const QuadtreeRectangleAvailability::RectangleWithLevel& b) noexcept;
+  static uint32_t findMaxLevelFromNode(
+      QuadtreeNode* pStopNode,
+      QuadtreeNode& node,
+      const glm::dvec2& position) noexcept;
+  static void createNodeChildrenIfNecessary(
+      QuadtreeNode& node,
+      const QuadtreeTilingScheme& tilingScheme) noexcept;
+};
+} // namespace CesiumGeometry