初始提交: UE5.3项目基础框架

Plugins/CesiumForUnreal/Source/ThirdParty/include/CesiumGeospatial/Ellipsoid.h

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+#pragma once
+
+#include "Cartographic.h"
+#include "Library.h"
+
+#include <CesiumUtility/Math.h>
+
+#include <glm/vec3.hpp>
+
+#include <optional>
+
+// The comments are copied here so that the doc comment always shows up in
+// Intellisense whether the default is toggled or not.
+#ifndef CESIUM_DISABLE_DEFAULT_ELLIPSOID
+// To keep from breaking our API, a lot of things now need default Ellipsoid
+// parameters. However, we shouldn't rely on these defaults internally, so
+// disabling them is a good way to get a compile-time check that they're not
+// being used. This macro allows us to toggle this check.
+#define CESIUM_DEFAULT_ELLIPSOID = CesiumGeospatial::Ellipsoid::WGS84
+#else
+// To keep from breaking our API, a lot of things now need default Ellipsoid
+// parameters. However, we shouldn't rely on these defaults internally, so
+// disabling them is a good way to get a compile-time check that they're not
+// being used. This macro allows us to toggle this check.
+#define CESIUM_DEFAULT_ELLIPSOID
+#endif
+
+namespace CesiumGeospatial {
+
+/**
+ * @brief A quadratic surface defined in Cartesian coordinates.
+ *
+ * The surface is defined by the equation `(x / a)^2 + (y / b)^2 + (z / c)^2 =
+ * 1`. This is primarily used by Cesium to represent the shape of planetary
+ * bodies. Rather than constructing this object directly, one of the provided
+ * constants is normally used.
+ */
+class CESIUMGEOSPATIAL_API Ellipsoid final {
+public:
+  /**
+   * @brief An Ellipsoid instance initialized to the WGS84 standard.
+   *
+   * The ellipsoid is initialized to the  World Geodetic System (WGS84)
+   * standard, as defined in
+   * https://earth-info.nga.mil/GandG/publications/tr8350.2/wgs84fin.pdf.
+   */
+  static /*constexpr*/ const Ellipsoid WGS84;
+
+  /**
+   * @brief An Ellipsoid with all three radii set to one meter.
+   */
+  static const Ellipsoid UNIT_SPHERE;
+
+  /**
+   * @brief Creates a new instance.
+   *
+   * @param x The radius in x-direction.
+   * @param y The radius in y-direction.
+   * @param z The radius in z-direction.
+   */
+  constexpr Ellipsoid(double x, double y, double z) noexcept
+      : Ellipsoid(glm::dvec3(x, y, z)) {}
+
+  /**
+   * @brief Creates a new instance.
+   *
+   * @param radii The radii in x-, y-, and z-direction.
+   */
+  constexpr Ellipsoid(const glm::dvec3& radii) noexcept
+      : _radii(radii),
+        _radiiSquared(radii.x * radii.x, radii.y * radii.y, radii.z * radii.z),
+        _oneOverRadii(1.0 / radii.x, 1.0 / radii.y, 1.0 / radii.z),
+        _oneOverRadiiSquared(
+            1.0 / (radii.x * radii.x),
+            1.0 / (radii.y * radii.y),
+            1.0 / (radii.z * radii.z)),
+        _centerToleranceSquared(CesiumUtility::Math::Epsilon1) {}
+
+  /**
+   * @brief Returns the radii in x-, y-, and z-direction.
+   */
+  constexpr const glm::dvec3& getRadii() const noexcept { return this->_radii; }
+
+  /**
+   * @brief Computes the normal of the plane tangent to the surface of the
+   * ellipsoid at the provided position.
+   *
+   * @param position The cartesian position for which to to determine the
+   * surface normal.
+   * @return The normal.
+   */
+  glm::dvec3 geodeticSurfaceNormal(const glm::dvec3& position) const noexcept;
+
+  /**
+   * @brief Computes the normal of the plane tangent to the surface of the
+   * ellipsoid at the provided position.
+   *
+   * @param cartographic The {@link Cartographic} position for which to to
+   * determine the surface normal.
+   * @return The normal.
+   */
+  glm::dvec3
+  geodeticSurfaceNormal(const Cartographic& cartographic) const noexcept;
+
+  /**
+   * @brief Converts the provided {@link Cartographic} to cartesian
+   * representation.
+   *
+   * @param cartographic The {@link Cartographic} position.
+   * @return The cartesian representation.
+   */
+  glm::dvec3
+  cartographicToCartesian(const Cartographic& cartographic) const noexcept;
+
+  /**
+   * @brief Converts the provided cartesian to a {@link Cartographic}
+   * representation.
+   *
+   * The result will be the empty optional if the given cartesian is at the
+   * center of this ellipsoid.
+   *
+   * @param cartesian The cartesian position.
+   * @return The {@link Cartographic} representation, or the empty optional if
+   * the cartesian is at the center of this ellipsoid.
+   */
+  std::optional<Cartographic>
+  cartesianToCartographic(const glm::dvec3& cartesian) const noexcept;
+
+  /**
+   * @brief Scales the given cartesian position along the geodetic surface
+   * normal so that it is on the surface of this ellipsoid.
+   *
+   * The result will be the empty optional if the position is at the center of
+   * this ellipsoid.
+   *
+   * @param cartesian The cartesian position.
+   * @return The scaled position, or the empty optional if
+   * the cartesian is at the center of this ellipsoid.
+   */
+  std::optional<glm::dvec3>
+  scaleToGeodeticSurface(const glm::dvec3& cartesian) const noexcept;
+
+  /**
+   * @brief Scales the provided cartesian position along the geocentric
+   * surface normal so that it is on the surface of this ellipsoid.
+   *
+   * @param cartesian The cartesian position to scale.
+   * @returns The scaled position, or the empty optional if the cartesian is at
+   * the center of this ellipsoid.
+   */
+  std::optional<glm::dvec3>
+  scaleToGeocentricSurface(const glm::dvec3& cartesian) const noexcept;
+
+  /**
+   * @brief The maximum radius in any dimension.
+   *
+   * @return The maximum radius.
+   */
+  constexpr double getMaximumRadius() const noexcept {
+    return glm::max(this->_radii.x, glm::max(this->_radii.y, this->_radii.z));
+  }
+
+  /**
+   * @brief The minimum radius in any dimension.
+   *
+   * @return The minimum radius.
+   */
+  constexpr double getMinimumRadius() const noexcept {
+    return glm::min(this->_radii.x, glm::min(this->_radii.y, this->_radii.z));
+  }
+
+  /**
+   * @brief Returns `true` if two elliposids are equal.
+   */
+  constexpr bool operator==(const Ellipsoid& rhs) const noexcept {
+    return this->_radii == rhs._radii;
+  };
+
+  /**
+   * @brief Returns `true` if two elliposids are *not* equal.
+   */
+  constexpr bool operator!=(const Ellipsoid& rhs) const noexcept {
+    return !(*this == rhs);
+  };
+
+private:
+  glm::dvec3 _radii;
+  glm::dvec3 _radiiSquared;
+  glm::dvec3 _oneOverRadii;
+  glm::dvec3 _oneOverRadiiSquared;
+  double _centerToleranceSquared;
+};
+} // namespace CesiumGeospatial