Add support for custom ellipsoids

CHANGES.md

@@ -2,6 +2,11 @@
 
 ### ? - ?
 
+##### Additions :tada:
+- Cesium for Unreal now supports using non-WGS84 ellipsoids.
+  - An `UCesiumEllipsoid` asset should be specified on the `Ellipsoid` field of an `ACesiumGeoreference`.
+  - To create a `UCesiumEllipsoid` asset, right-click in the Content Drawer and select "Data Asset" under "Miscellaneous." Choose "Cesium Ellipsoid" from the menu that appears.
+
 ##### Fixes :wrench:
 
 - Removed unnecessary alpha check when selecting translucent base materials.

Source/CesiumEditor/Private/CesiumGlobeAnchorCustomization.cpp

@@ -7,6 +7,7 @@
 #include "DetailCategoryBuilder.h"
 #include "DetailLayoutBuilder.h"
 #include "IDetailGroup.h"
+#include "Widgets/SToolTip.h"
 
 FName FCesiumGlobeAnchorCustomization::RegisteredLayoutName;
 
@@ -201,32 +202,63 @@ void UCesiumGlobeAnchorDerivedProperties::PostEditChangeProperty(
     this->GlobeAnchor->Modify();
     this->GlobeAnchor->MoveToEarthCenteredEarthFixedPosition(
         FVector(this->X, this->Y, this->Z));
-  } else if (
-      propertyName == GET_MEMBER_NAME_CHECKED(
-                          UCesiumGlobeAnchorDerivedProperties,
-                          Longitude) ||
-      propertyName == GET_MEMBER_NAME_CHECKED(
-                          UCesiumGlobeAnchorDerivedProperties,
-                          Latitude) ||
-      propertyName == GET_MEMBER_NAME_CHECKED(
-                          UCesiumGlobeAnchorDerivedProperties,
-                          Height)) {
-    this->GlobeAnchor->Modify();
-    this->GlobeAnchor->MoveToLongitudeLatitudeHeight(
-        FVector(this->Longitude, this->Latitude, this->Height));
-  } else if (
-      propertyName ==
-          GET_MEMBER_NAME_CHECKED(UCesiumGlobeAnchorDerivedProperties, Pitch) ||
-      propertyName ==
-          GET_MEMBER_NAME_CHECKED(UCesiumGlobeAnchorDerivedProperties, Yaw) ||
-      propertyName ==
-          GET_MEMBER_NAME_CHECKED(UCesiumGlobeAnchorDerivedProperties, Roll)) {
-    this->GlobeAnchor->Modify();
-    this->GlobeAnchor->SetEastSouthUpRotation(
-        FRotator(this->Pitch, this->Yaw, this->Roll).Quaternion());
+  } else if (true) {
+    if (propertyName == GET_MEMBER_NAME_CHECKED(
+                            UCesiumGlobeAnchorDerivedProperties,
+                            Longitude) ||
+        propertyName == GET_MEMBER_NAME_CHECKED(
+                            UCesiumGlobeAnchorDerivedProperties,
+                            Latitude) ||
+        propertyName == GET_MEMBER_NAME_CHECKED(
+                            UCesiumGlobeAnchorDerivedProperties,
+                            Height)) {
+      this->GlobeAnchor->Modify();
+      this->GlobeAnchor->MoveToLongitudeLatitudeHeight(
+          FVector(this->Longitude, this->Latitude, this->Height));
+    } else if (
+        propertyName == GET_MEMBER_NAME_CHECKED(
+                            UCesiumGlobeAnchorDerivedProperties,
+                            Pitch) ||
+        propertyName ==
+            GET_MEMBER_NAME_CHECKED(UCesiumGlobeAnchorDerivedProperties, Yaw) ||
+        propertyName == GET_MEMBER_NAME_CHECKED(
+                            UCesiumGlobeAnchorDerivedProperties,
+                            Roll)) {
+      this->GlobeAnchor->Modify();
+      this->GlobeAnchor->SetEastSouthUpRotation(
+          FRotator(this->Pitch, this->Yaw, this->Roll).Quaternion());
+    }
   }
 }
 
+bool UCesiumGlobeAnchorDerivedProperties::CanEditChange(
+    const FProperty* InProperty) const {
+  const FName Name = InProperty->GetFName();
+
+  // Valid georeference, nothing to disable
+  if (IsValid(this->GlobeAnchor->ResolveGeoreference())) {
+    return true;
+  }
+
+  return Name != GET_MEMBER_NAME_CHECKED(
+                     UCesiumGlobeAnchorDerivedProperties,
+                     Longitude) &&
+         Name != GET_MEMBER_NAME_CHECKED(
+                     UCesiumGlobeAnchorDerivedProperties,
+                     Latitude) &&
+         Name != GET_MEMBER_NAME_CHECKED(
+                     UCesiumGlobeAnchorDerivedProperties,
+                     Height) &&
+         Name != GET_MEMBER_NAME_CHECKED(
+                     UCesiumGlobeAnchorDerivedProperties,
+                     Pitch) &&
+         Name != GET_MEMBER_NAME_CHECKED(
+                     UCesiumGlobeAnchorDerivedProperties,
+                     Yaw) &&
+         Name !=
+             GET_MEMBER_NAME_CHECKED(UCesiumGlobeAnchorDerivedProperties, Roll);
+}
+
 void UCesiumGlobeAnchorDerivedProperties::Initialize(
     UCesiumGlobeAnchorComponent* GlobeAnchorComponent) {
   this->GlobeAnchor = GlobeAnchorComponent;
@@ -240,16 +272,21 @@ void UCesiumGlobeAnchorDerivedProperties::Tick(float DeltaTime) {
     this->Y = position.Y;
     this->Z = position.Z;
 
-    FVector llh = this->GlobeAnchor->GetLongitudeLatitudeHeight();
-    this->Longitude = llh.X;
-    this->Latitude = llh.Y;
-    this->Height = llh.Z;
-
-    FQuat rotation = this->GlobeAnchor->GetEastSouthUpRotation();
-    FRotator rotator = rotation.Rotator();
-    this->Roll = rotator.Roll;
-    this->Pitch = rotator.Pitch;
-    this->Yaw = rotator.Yaw;
+    // We can't transform the GlobeAnchor's ECEF coordinates back to
+    // cartographic & rotation without a valid georeference to know what
+    // ellipsoid to use.
+    if (IsValid(this->GlobeAnchor->ResolveGeoreference())) {
+      FVector llh = this->GlobeAnchor->GetLongitudeLatitudeHeight();
+      this->Longitude = llh.X;
+      this->Latitude = llh.Y;
+      this->Height = llh.Z;
+
+      FQuat rotation = this->GlobeAnchor->GetEastSouthUpRotation();
+      FRotator rotator = rotation.Rotator();
+      this->Roll = rotator.Roll;
+      this->Pitch = rotator.Pitch;
+      this->Yaw = rotator.Yaw;
+    }
   }
 }
 

Source/CesiumEditor/Private/CesiumGlobeAnchorCustomization.h

@@ -137,6 +137,7 @@ class UCesiumGlobeAnchorDerivedProperties : public UObject,
 
   virtual void PostEditChangeProperty(
       struct FPropertyChangedEvent& PropertyChangedEvent) override;
+  virtual bool CanEditChange(const FProperty* InProperty) const override;
 
   void Initialize(UCesiumGlobeAnchorComponent* GlobeAnchor);
 

Source/CesiumRuntime/Private/Cesium3DTileset.cpp

@@ -149,6 +149,9 @@ ACesiumGeoreference* ACesium3DTileset::ResolveGeoreference() {
     this->ResolvedGeoreference->OnGeoreferenceUpdated.AddUniqueDynamic(
         pRoot,
         &UCesium3DTilesetRoot::HandleGeoreferenceUpdated);
+    this->ResolvedGeoreference->OnEllipsoidChanged.AddUniqueDynamic(
+        this,
+        &ACesium3DTileset::HandleOnGeoreferenceEllipsoidChanged);
 
     // Update existing tile positions, if any.
     pRoot->HandleGeoreferenceUpdated();
@@ -471,10 +474,14 @@ void ACesium3DTileset::OnFocusEditorViewportOnThis() {
       *this->GetName());
 
   struct CalculateECEFCameraPosition {
+    const CesiumGeospatial::Ellipsoid& ellipsoid;
+
     glm::dvec3 operator()(const CesiumGeometry::BoundingSphere& sphere) {
       const glm::dvec3& center = sphere.getCenter();
       glm::dmat4 ENU =
-          CesiumGeospatial::GlobeTransforms::eastNorthUpToFixedFrame(center);
+          CesiumGeospatial::GlobeTransforms::eastNorthUpToFixedFrame(
+              center,
+              ellipsoid);
       glm::dvec3 offset =
           sphere.getRadius() *
           glm::normalize(
@@ -487,7 +494,9 @@ void ACesium3DTileset::OnFocusEditorViewportOnThis() {
     operator()(const CesiumGeometry::OrientedBoundingBox& orientedBoundingBox) {
       const glm::dvec3& center = orientedBoundingBox.getCenter();
       glm::dmat4 ENU =
-          CesiumGeospatial::GlobeTransforms::eastNorthUpToFixedFrame(center);
+          CesiumGeospatial::GlobeTransforms::eastNorthUpToFixedFrame(
+              center,
+              ellipsoid);
       const glm::dmat3& halfAxes = orientedBoundingBox.getHalfAxes();
       glm::dvec3 offset =
           glm::length(halfAxes[0] + halfAxes[1] + halfAxes[2]) *
@@ -525,9 +534,12 @@ void ACesium3DTileset::OnFocusEditorViewportOnThis() {
 
   ACesiumGeoreference* pGeoreference = this->ResolveGeoreference();
 
+  const CesiumGeospatial::Ellipsoid& ellipsoid =
+      pGeoreference->GetEllipsoid()->GetNativeEllipsoid();
+
   // calculate unreal camera position
   glm::dvec3 ecefCameraPosition =
-      std::visit(CalculateECEFCameraPosition{}, boundingVolume);
+      std::visit(CalculateECEFCameraPosition{ellipsoid}, boundingVolume);
   FVector unrealCameraPosition =
       pGeoreference->TransformEarthCenteredEarthFixedPositionToUnreal(
           VecMath::createVector(ecefCameraPosition));
@@ -591,6 +603,13 @@ void ACesium3DTileset::UpdateTransformFromCesium() {
   }
 }
 
+void ACesium3DTileset::HandleOnGeoreferenceEllipsoidChanged(
+    UCesiumEllipsoid* OldEllipsoid,
+    UCesiumEllipsoid* NewEllpisoid) {
+  UE_LOG(LogCesium, Warning, TEXT("Ellipsoid changed"));
+  this->RefreshTileset();
+}
+
 // Called when the game starts or when spawned
 void ACesium3DTileset::BeginPlay() {
   Super::BeginPlay();
@@ -708,8 +727,13 @@ class UnrealResourcePreparer
           &(*this->_pActor->_metadataDescription_DEPRECATED);
     }
 
+    const CesiumGeospatial::Ellipsoid& ellipsoid = tileLoadResult.ellipsoid;
+
     TUniquePtr<UCesiumGltfComponent::HalfConstructed> pHalf =
-        UCesiumGltfComponent::CreateOffGameThread(transform, options);
+        UCesiumGltfComponent::CreateOffGameThread(
+            transform,
+            options,
+            ellipsoid);
 
     return asyncSystem.createResolvedFuture(
         Cesium3DTilesSelection::TileLoadResultAndRenderResources{
@@ -1052,6 +1076,9 @@ void ACesium3DTileset::LoadTileset() {
     this->BoundingVolumePoolComponent->initPool(this->OcclusionPoolSize);
   }
 
+  CesiumGeospatial::Ellipsoid pNativeEllipsoid =
+      this->ResolveGeoreference()->GetEllipsoid()->GetNativeEllipsoid();
+
   ACesiumCreditSystem* pCreditSystem = this->ResolvedCreditSystem;
 
   Cesium3DTilesSelection::TilesetExternals externals{
@@ -1072,6 +1099,8 @@ void ACesium3DTileset::LoadTileset() {
 
   Cesium3DTilesSelection::TilesetOptions options;
 
+  options.ellipsoid = pNativeEllipsoid;
+
   options.enableOcclusionCulling =
       GetDefault<UCesiumRuntimeSettings>()
           ->EnableExperimentalOcclusionCullingFeature &&
@@ -1545,7 +1574,8 @@ std::vector<FCesiumCamera> ACesium3DTileset::GetSceneCaptures() const {
 /*static*/ Cesium3DTilesSelection::ViewState
 ACesium3DTileset::CreateViewStateFromViewParameters(
     const FCesiumCamera& camera,
-    const glm::dmat4& unrealWorldToTileset) {
+    const glm::dmat4& unrealWorldToTileset,
+    UCesiumEllipsoid* ellipsoid) {
 
   double horizontalFieldOfView =
       FMath::DegreesToRadians(camera.FieldOfViewDegrees);
@@ -1595,7 +1625,8 @@ ACesium3DTileset::CreateViewStateFromViewParameters(
       tilesetCameraUp,
       size,
       horizontalFieldOfView,
-      verticalFieldOfView);
+      verticalFieldOfView,
+      ellipsoid->GetNativeEllipsoid());
 }
 
 #if WITH_EDITOR
@@ -2044,10 +2075,14 @@ void ACesium3DTileset::Tick(float DeltaTime) {
     return;
   }
 
+  UCesiumEllipsoid* ellipsoid = this->ResolveGeoreference()->GetEllipsoid();
+
   std::vector<Cesium3DTilesSelection::ViewState> frustums;
   for (const FCesiumCamera& camera : cameras) {
-    frustums.push_back(
-        CreateViewStateFromViewParameters(camera, unrealWorldToCesiumTileset));
+    frustums.push_back(CreateViewStateFromViewParameters(
+        camera,
+        unrealWorldToCesiumTileset,
+        ellipsoid));
   }
 
   const Cesium3DTilesSelection::ViewUpdateResult* pResult;