初始提交: UE5.3项目基础框架

Plugins/CesiumForUnreal/Source/ThirdParty/include/Cesium3DTilesSelection/RasterMappedTo3DTile.h

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+#pragma once
+
+#include "IPrepareRendererResources.h"
+
+#include <CesiumGeometry/Rectangle.h>
+#include <CesiumGeospatial/Projection.h>
+#include <CesiumRasterOverlays/RasterOverlayTile.h>
+#include <CesiumUtility/IntrusivePointer.h>
+
+#include <memory>
+
+namespace Cesium3DTilesSelection {
+
+class Tile;
+
+/**
+ * @brief The result of applying a {@link CesiumRasterOverlays::RasterOverlayTile} to geometry.
+ *
+ * Instances of this class are used by a {@link Tile} in order to map
+ * imagery data that is given as {@link CesiumRasterOverlays::RasterOverlayTile} instances
+ * to the 2D region that is covered by the tile geometry.
+ */
+class RasterMappedTo3DTile final {
+public:
+  /**
+   * @brief The states indicating whether the raster tile is attached to the
+   * geometry.
+   */
+  enum class AttachmentState {
+    /**
+     * @brief This raster tile is not yet attached to the geometry at all.
+     */
+    Unattached = 0,
+
+    /**
+     * @brief This raster tile is attached to the geometry, but it is a
+     * temporary, low-res version usable while the full-res version is loading.
+     */
+    TemporarilyAttached = 1,
+
+    /**
+     * @brief This raster tile is attached to the geometry.
+     */
+    Attached = 2
+  };
+
+  /**
+   * @brief Creates a new instance.
+   *
+   * @param pRasterTile The {@link CesiumRasterOverlays::RasterOverlayTile} that is mapped to the
+   * geometry.
+   * @param textureCoordinateIndex The index of the texture coordinates to use
+   * with this mapped raster overlay.
+   */
+  RasterMappedTo3DTile(
+      const CesiumUtility::IntrusivePointer<
+          CesiumRasterOverlays::RasterOverlayTile>& pRasterTile,
+      int32_t textureCoordinateIndex);
+
+  /**
+   * @brief Returns a {@link CesiumRasterOverlays::RasterOverlayTile} that is currently loading.
+   *
+   * The caller has to check the exact state of this tile, using
+   * {@link Tile::getState}.
+   *
+   * @return The tile that is loading, or `nullptr`.
+   */
+  CesiumRasterOverlays::RasterOverlayTile* getLoadingTile() noexcept {
+    return this->_pLoadingTile.get();
+  }
+
+  /** @copydoc getLoadingTile */
+  const CesiumRasterOverlays::RasterOverlayTile*
+  getLoadingTile() const noexcept {
+    return this->_pLoadingTile.get();
+  }
+
+  /**
+   * @brief Returns the {@link CesiumRasterOverlays::RasterOverlayTile} that represents the imagery
+   * data that is ready to render.
+   *
+   * This will be `nullptr` when the tile data has not yet been loaded.
+   *
+   * @return The tile, or `nullptr`.
+   */
+  CesiumRasterOverlays::RasterOverlayTile* getReadyTile() noexcept {
+    return this->_pReadyTile.get();
+  }
+
+  /** @copydoc getReadyTile */
+  const CesiumRasterOverlays::RasterOverlayTile* getReadyTile() const noexcept {
+    return this->_pReadyTile.get();
+  }
+
+  /**
+   * @brief Returns an identifier for the texture coordinates of this tile.
+   *
+   * The texture coordinates for this raster are found in the glTF as an
+   * attribute named `_CESIUMOVERLAY_n` where `n` is this value.
+   *
+   * @return The texture coordinate ID.
+   */
+  int32_t getTextureCoordinateID() const noexcept {
+    return this->_textureCoordinateID;
+  }
+
+  /**
+   * @brief Sets the texture coordinate ID.
+   *
+   * @see getTextureCoordinateID
+   *
+   * @param textureCoordinateID The ID.
+   */
+  void setTextureCoordinateID(int32_t textureCoordinateID) noexcept {
+    this->_textureCoordinateID = textureCoordinateID;
+  }
+
+  /**
+   * @brief Returns the translation that converts between the geometry texture
+   * coordinates and the texture coordinates that should be used to sample this
+   * raster texture.
+   *
+   * `rasterCoordinates = geometryCoordinates * scale + translation`
+   *
+   * @returns The translation.
+   */
+  const glm::dvec2& getTranslation() const noexcept {
+    return this->_translation;
+  }
+
+  /**
+   * @brief Returns the scaling that converts between the geometry texture
+   * coordinates and the texture coordinates that should be used to sample this
+   * raster texture.
+   *
+   * @see getTranslation
+   *
+   * @returns The scaling.
+   */
+  const glm::dvec2& getScale() const noexcept { return this->_scale; }
+
+  /**
+   * @brief Indicates whether this overlay tile is currently attached to its
+   * owning geometry tile.
+   *
+   * When a raster overlay tile is attached to a geometry tile,
+   * {@link IPrepareRendererResources::attachRasterInMainThread} is invoked.
+   * When it is detached,
+   * {@link IPrepareRendererResources::detachRasterInMainThread} is invoked.
+   */
+  AttachmentState getState() const noexcept { return this->_state; }
+
+  /**
+   * @brief Update this tile during the update of its owner.
+   *
+   * This is only supposed to be called by
+   * `TilesetContentManager::updateDoneState`. It will return whether there is a
+   * more detailed version of the raster data available.
+   *
+   * @param prepareRendererResources The {@link IPrepareRendererResources} used to
+   * create render resources for raster overlay
+   * @param tile The owner tile.
+   * @return The {@link CesiumRasterOverlays::RasterOverlayTile::MoreDetailAvailable} state.
+   */
+  CesiumRasterOverlays::RasterOverlayTile::MoreDetailAvailable
+  update(IPrepareRendererResources& prepareRendererResources, Tile& tile);
+
+  /**
+   * @copydoc CesiumRasterOverlays::RasterOverlayTile::isMoreDetailAvailable
+   */
+  bool isMoreDetailAvailable() const noexcept;
+
+  /**
+   * @brief Detach the raster from the given tile.
+   * @param prepareRendererResources The IPrepareRendererResources used to
+   * detach raster overlay from the tile geometry
+   * @param tile The owner tile.
+   */
+  void detachFromTile(
+      IPrepareRendererResources& prepareRendererResources,
+      Tile& tile) noexcept;
+
+  /**
+   * @brief Does a throttled load of the mapped {@link CesiumRasterOverlays::RasterOverlayTile}.
+   *
+   * @return If the mapped tile is already in the process of loading or it has
+   * already finished loading, this method does nothing and returns true. If too
+   * many loads are already in progress, this method does nothing and returns
+   * false. Otherwise, it begins the asynchronous process to load the tile and
+   * returns true.
+   */
+  bool loadThrottled() noexcept;
+
+  /**
+   * @brief Creates a maping between a {@link CesiumRasterOverlays::RasterOverlay} and a {@link Tile}.
+   *
+   * The returned mapping will be to a placeholder {@link CesiumRasterOverlays::RasterOverlayTile} if
+   * the overlay's tile provider is not yet ready (i.e. it's still a
+   * placeholder) or if the overlap between the tile and the raster overlay
+   * cannot yet be determined because the projected rectangle of the tile is not
+   * yet known.
+   *
+   * Returns a pointer to the created `RasterMappedTo3DTile` in the Tile's
+   * {@link Tile::getMappedRasterTiles} collection. Note that this pointer may
+   * become invalid as soon as another item is added to or removed from this
+   * collection.
+   *
+   * @param maximumScreenSpaceError The maximum screen space error that is used
+   * for the current tile
+   * @param tileProvider The overlay tile provider to map to the tile. This may
+   * be a placeholder if the tile provider is not yet ready.
+   * @param placeholder The placeholder tile provider for this overlay. This is
+   * always a placeholder, even if the tile provider is already ready.
+   * @param tile The tile to which to map the overlay.
+   * @param missingProjections The list of projections for which there are not
+   * yet any texture coordiantes. On return, the given overlay's Projection may
+   * be added to this collection if the Tile does not yet have texture
+   * coordinates for the Projection and the Projection is not already in the
+   * collection.
+   * @param ellipsoid The {@link CesiumGeospatial::Ellipsoid}.
+   * @return A pointer the created mapping, which may be to a placeholder, or
+   * nullptr if no mapping was created at all because the Tile does not overlap
+   * the raster overlay.
+   */
+  static RasterMappedTo3DTile* mapOverlayToTile(
+      double maximumScreenSpaceError,
+      CesiumRasterOverlays::RasterOverlayTileProvider& tileProvider,
+      CesiumRasterOverlays::RasterOverlayTileProvider& placeholder,
+      Tile& tile,
+      std::vector<CesiumGeospatial::Projection>& missingProjections,
+      const CesiumGeospatial::Ellipsoid& ellipsoid CESIUM_DEFAULT_ELLIPSOID);
+
+private:
+  void computeTranslationAndScale(const Tile& tile);
+
+  CesiumUtility::IntrusivePointer<CesiumRasterOverlays::RasterOverlayTile>
+      _pLoadingTile;
+  CesiumUtility::IntrusivePointer<CesiumRasterOverlays::RasterOverlayTile>
+      _pReadyTile;
+  int32_t _textureCoordinateID;
+  glm::dvec2 _translation;
+  glm::dvec2 _scale;
+  AttachmentState _state;
+  bool _originalFailed;
+};
+
+} // namespace Cesium3DTilesSelection