Merge pull request #1083 from CesiumGS/culling-volume-crash

Fix crash while creating culling volume when the camera is very far from the globe

CHANGES.md

@@ -8,6 +8,7 @@
 - Removed `Math::perpVector`. Use `glm::perp` from `<glm/gtx/perpendicular.hpp>` instead.
 - Using Cesium Native in non-cmake projects now requires manually defining `GLM_ENABLE_EXPERIMENTAL`.
 - cesium-native no longer uses the `GLM_FORCE_SIZE_T_LENGTH` option with the `glm` library
+- `CullingVolume` has been moved from the `Cesium3DTilesSelection` namespace to the `CesiumGeometry` namespace.
 
 ##### Additions :tada:
 
@@ -24,6 +25,7 @@
 - Fixed a bug in `SharedAssetDepot` that could cause assertion failures in debug builds, and could rarely cause premature deletion of shared assets even in release builds.
 - Fixed a bug that could cause `Tileset::sampleHeightMostDetailed` to return a height that is not the highest one when the sampled tileset contained multiple heights at the given location.
 - `LayerJsonTerrainLoader` will now log errors and warnings when failing to load a `.terrain` file referenced in the layer.json, instead of silently ignoring them.
+- Fixed a crash in `CullingVolume` when the camera was very far away from the globe.
 
 ### v0.43.0 - 2025-01-02
 

Cesium3DTilesSelection/include/Cesium3DTilesSelection/ViewState.h

@@ -175,7 +175,7 @@ class CESIUM3DTILESSELECTION_API ViewState final {
   const double _sseDenominator;
   const std::optional<CesiumGeospatial::Cartographic> _positionCartographic;
 
-  const CullingVolume _cullingVolume;
+  const CesiumGeometry::CullingVolume _cullingVolume;
 };
 
 } // namespace Cesium3DTilesSelection

CesiumGeometry/include/CesiumGeometry/CullingVolume.h

@@ -2,7 +2,7 @@
 
 #include <CesiumGeometry/Plane.h>
 
-namespace Cesium3DTilesSelection {
+namespace CesiumGeometry {
 
 /**
  * @brief A culling volume, defined by four planes.
@@ -58,4 +58,4 @@ CullingVolume createCullingVolume(
     const glm::dvec3& up,
     double fovx,
     double fovy) noexcept;
-} // namespace Cesium3DTilesSelection
+} // namespace CesiumGeometry

CesiumGeometry/src/CullingVolume.cpp

@@ -5,7 +5,11 @@
 #include <glm/geometric.hpp>
 #include <glm/trigonometric.hpp>
 
-namespace Cesium3DTilesSelection {
+#include <algorithm>
+#include <cmath>
+#include <limits>
+
+namespace CesiumGeometry {
 
 CullingVolume createCullingVolume(
     const glm::dvec3& position,
@@ -18,7 +22,11 @@ CullingVolume createCullingVolume(
   const double r = glm::tan(0.5 * fovx);
   const double l = -r;
 
-  const double n = 1.0;
+  const double positionLen = glm::length(position);
+  const double n = std::max(
+      1.0,
+      std::nextafter(positionLen, std::numeric_limits<double>::max()) -
+          positionLen);
 
   // TODO: this is all ported directly from CesiumJS, can probably be refactored
   // to be more efficient with GLM.
@@ -67,4 +75,4 @@ CullingVolume createCullingVolume(
 
   return {leftPlane, rightPlane, topPlane, bottomPlane};
 }
-} // namespace Cesium3DTilesSelection
+} // namespace CesiumGeometry

CesiumGeometry/test/TestCullingVolume.cpp

@@ -0,0 +1,34 @@
+#include <CesiumGeometry/CullingVolume.h>
+#include <CesiumUtility/Math.h>
+
+#include <doctest/doctest.h>
+#include <glm/ext/matrix_transform.hpp>
+#include <glm/ext/vector_double3.hpp>
+#include <glm/fwd.hpp>
+#include <glm/gtx/euler_angles.hpp>
+
+#include <cmath>
+
+using namespace doctest;
+using namespace CesiumGeometry;
+using namespace CesiumUtility;
+
+TEST_CASE("CullingVolume::createCullingVolume") {
+  SUBCASE("Shouldn't crash when too far from the globe") {
+    CHECK_NOTHROW(createCullingVolume(
+        glm::dvec3(1e20, 1e20, 1e20),
+        glm::dvec3(0, 0, 1),
+        glm::dvec3(0, 1, 0),
+        Math::PiOverTwo,
+        Math::PiOverTwo));
+  }
+
+  SUBCASE("Shouldn't crash at the center of the globe") {
+    CHECK_NOTHROW(createCullingVolume(
+        glm::dvec3(0, 0, 0),
+        glm::dvec3(0, 0, 1),
+        glm::dvec3(0, 1, 0),
+        Math::PiOverTwo,
+        Math::PiOverTwo));
+  }
+}