Merge remote-tracking branch 'origin/shared-assets' into shared-asset…

…s-wip

CHANGES.md

@@ -1,5 +1,17 @@
 # Change Log
 
+### Next Version - Not Released Yet
+
+##### Additions :tada:
+
+- Added `CircumscribedGroundHeight` property to `CesiumSunSky`. It defaults to 0, which is consistent with the previous behavior. It can be set to a larger value (like 40) to avoid dark splotchy artifacts when zoomed out far from the globe in certain tilesets where geometry extends very far beyond the ellipsoid in the low-detail representation, such as Google Photorealistic 3D Tiles.
+
+##### Fixes :wrench:
+
+- Fixed a bug that caused incorrect lighting for tilesets using `KHR_materials_unlit`.
+- Reduced the memory used by tiles with `KHR_materials_unlit`.
+- `CesiumGlobeAnchor` properties are no longer shown on the main `CesiumSunSky` Details panel, because it is almost never necessary to set these. They can still be set on the component's own Details panel if needed.
+
 ### v2.9.0 - 2024-10-01
 
 ##### Additions :tada:

Source/CesiumRuntime/Private/CesiumGltfComponent.cpp

@@ -269,13 +269,23 @@ static void computeTangentSpace(TArray<FStaticMeshBuildVertex>& vertices) {
   genTangSpaceDefault(&MikkTContext);
 }
 
-static void setUniformNormals(
+static void setUnlitNormals(
     TArray<FStaticMeshBuildVertex>& vertices,
-    TMeshVector3 normal) {
+    const CesiumGeospatial::Ellipsoid& ellipsoid,
+    const glm::dmat4& vertexToEllipsoidFixed) {
+  glm::dmat4 ellipsoidFixedToVertex =
+      glm::affineInverse(vertexToEllipsoidFixed);
+
   for (int i = 0; i < vertices.Num(); i++) {
     FStaticMeshBuildVertex& v = vertices[i];
     v.TangentX = v.TangentY = TMeshVector3(0.0f);
-    v.TangentZ = normal;
+
+    glm::dvec3 positionFixed = glm::dvec3(
+        vertexToEllipsoidFixed *
+        glm::dvec4(VecMath::createVector3D(FVector(v.Position)), 1.0));
+    glm::dvec3 normal = ellipsoid.geodeticSurfaceNormal(positionFixed);
+    v.TangentZ = FVector3f(VecMath::createVector(
+        glm::normalize(ellipsoidFixedToVertex * glm::dvec4(normal, 0.0))));
   }
 }
 
@@ -1349,7 +1359,10 @@ static void loadPrimitive(
   // vertices shared by multiple triangles. If we don't have tangents, but
   // need them, we need to use a tangent space generation algorithm which
   // requires duplicated vertices.
-  bool duplicateVertices = !hasNormals || (needsTangents && !hasTangents);
+  bool normalsAreRequired = !primitiveResult.isUnlit;
+  bool needToGenerateFlatNormals = normalsAreRequired && !hasNormals;
+  bool needToGenerateTangents = needsTangents && !hasTangents;
+  bool duplicateVertices = needToGenerateFlatNormals || needToGenerateTangents;
   duplicateVertices =
       duplicateVertices && primitive.mode != MeshPrimitive::Mode::POINTS;
 
@@ -1512,6 +1525,13 @@ static void loadPrimitive(
     }
   }
 
+  double scale = 1.0 / CesiumPrimitiveData::positionScaleFactor;
+  glm::dmat4 scaleMatrix = glm::dmat4(
+      glm::dvec4(scale, 0.0, 0.0, 0.0),
+      glm::dvec4(0.0, scale, 0.0, 0.0),
+      glm::dvec4(0.0, 0.0, scale, 0.0),
+      glm::dvec4(0.0, 0.0, 0.0, 1.0));
+
   // TangentX: Tangent
   // TangentY: Bi-tangent
   // TangentZ: Normal
@@ -1543,16 +1563,10 @@ static void loadPrimitive(
     }
   } else {
     if (primitiveResult.isUnlit) {
-      glm::dvec3 ecefCenter = glm::dvec3(
-          transform *
-          glm::dvec4(VecMath::createVector3D(RenderData->Bounds.Origin), 1.0));
-      TMeshVector3 upDir = TMeshVector3(VecMath::createVector(
-          glm::affineInverse(transform) *
-          glm::dvec4(
-              ellipsoid.geodeticSurfaceNormal(glm::dvec3(ecefCenter)),
-              0.0)));
-      upDir.Y *= -1;
-      setUniformNormals(StaticMeshBuildVertices, upDir);
+      setUnlitNormals(
+          StaticMeshBuildVertices,
+          ellipsoid,
+          transform * yInvertMatrix * scaleMatrix);
     } else {
       TRACE_CPUPROFILER_EVENT_SCOPE(Cesium::ComputeFlatNormals)
       computeFlatNormals(StaticMeshBuildVertices);
@@ -1687,13 +1701,6 @@ static void loadPrimitive(
   primitiveResult.RenderData = std::move(RenderData);
   primitiveResult.pCollisionMesh = nullptr;
 
-  double scale = 1.0 / CesiumPrimitiveData::positionScaleFactor;
-  glm::dmat4 scaleMatrix = glm::dmat4(
-      glm::dvec4(scale, 0.0, 0.0, 0.0),
-      glm::dvec4(0.0, scale, 0.0, 0.0),
-      glm::dvec4(0.0, 0.0, scale, 0.0),
-      glm::dvec4(0.0, 0.0, 0.0, 1.0));
-
   primitiveResult.transform = transform * yInvertMatrix * scaleMatrix;
 
   if (primitive.mode != MeshPrimitive::Mode::POINTS &&

Source/CesiumRuntime/Private/CesiumSunSky.cpp

@@ -535,7 +535,8 @@ void ACesiumSunSky::UpdateAtmosphereRadius() {
       pGeoreference->TransformUnrealPositionToLongitudeLatitudeHeight(location);
 
   // An atmosphere of this radius should circumscribe all Earth terrain.
-  double maxRadius = pEllipsoid->GetMaximumRadius();
+  double maxRadius =
+      pEllipsoid->GetMaximumRadius() + this->CircumscribedGroundHeight * 1000.0;
 
   if (llh.Z / 1000.0 > this->CircumscribedGroundThreshold) {
     this->SetSkyAtmosphereGroundRadius(

Source/CesiumRuntime/Public/CesiumSunSky.h

@@ -48,7 +48,7 @@ class CESIUMRUNTIME_API ACesiumSunSky : public AActor {
   /**
    * The Globe Anchor Component that precisely ties this Actor to the Globe.
    */
-  UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category = "Cesium")
+  UPROPERTY(EditDefaultsOnly, BlueprintReadOnly, Category = Components)
   UCesiumGlobeAnchorComponent* GlobeAnchor;
 
   /**
@@ -295,6 +295,21 @@ class CESIUMRUNTIME_API ACesiumSunSky : public AActor {
       Category = "Cesium|Atmosphere")
   double CircumscribedGroundThreshold = 100.0;
 
+  /**
+   * The height at which to place the bottom of the atmosphere when the player
+   * pawn is above the CircumscribedGroundThreshold. This is expressed as a
+   * height in kilometers above the maximum radius of the ellipsoid (usually
+   * WGS84). To avoid dark splotchy artifacts in the atmosphere when zoomed out
+   * far from the globe, this value must be above the greatest height achieved
+   * by any part of the tileset.
+   */
+  UPROPERTY(
+      EditAnywhere,
+      BlueprintReadWrite,
+      meta = (EditCondition = "UpdateAtmosphereAtRuntime"),
+      Category = "Cesium|Atmosphere")
+  double CircumscribedGroundHeight = 0.0;
+
   /**
    * The height of the atmosphere layer above the ground, in kilometers. This
    * value is automatically scaled according to the CesiumGeoreference Scale and