Fix crash in Camera::computeFitViewEyePosition with parallel dir/up

dir^up becomes a zero vector when the view direction and up vector are parallel, producing an invalid zero-normal plane. Plane::distanceToOrigin() then asserts/aborts (CVF_ASSERT, always active). Fall back to an arbitrary axis to compute a valid right vector in this degenerate case.

ApplicationLibCode/UnitTests/CMakeLists.txt

@@ -168,6 +168,7 @@ set(SOURCE_UNITTEST_FILES
     ${CMAKE_CURRENT_LIST_DIR}/RimPolygonInViewCollection-Test.cpp
     ${CMAKE_CURRENT_LIST_DIR}/RimSurfaceInViewCollection-Test.cpp
     ${CMAKE_CURRENT_LIST_DIR}/RimViewController-Test.cpp
+    ${CMAKE_CURRENT_LIST_DIR}/CvfCameraCrashTriage-Test.cpp
     ${CMAKE_CURRENT_LIST_DIR}/RiaNameUniquenessTools-Test.cpp
     ${CMAKE_CURRENT_LIST_DIR}/RifVtkSurfaceImporter-Test.cpp
     ${CMAKE_CURRENT_LIST_DIR}/RifVtkReader-Test.cpp

ApplicationLibCode/UnitTests/CvfCameraCrashTriage-Test.cpp

@@ -0,0 +1,29 @@
+#include "gtest/gtest.h"
+
+#include "cvfBoundingBox.h"
+#include "cvfCamera.h"
+
+using namespace cvf;
+
+//--------------------------------------------------------------------------------------------------
+/// computeFitViewEyePosition() used to assert/abort (CVF_ASSERT in Plane::distanceToOrigin) when
+/// the view direction and up vector are parallel: dir^up then becomes a zero vector, producing an
+/// invalid (zero-normal) plane used internally. Reproduces the crash reported from
+/// caf::Viewer::zoomAll() with a degenerate camera orientation.
+//--------------------------------------------------------------------------------------------------
+TEST( CvfCameraCrashTriageTest, FitViewWithParallelDirAndUpDoesNotCrash )
+{
+    Camera c;
+
+    BoundingBox bb;
+    bb.add( Vec3d( 0, 0, 0 ) );
+    bb.add( Vec3d( 1, 1, 1 ) );
+
+    Vec3d  inViewDir( 0, 0, 1 );
+    Vec3d  inUp( 0, 0, 1 );
+    double coverageFactor = 0.9;
+
+    Vec3d eye = Camera::computeFitViewEyePosition( bb, inViewDir, inUp, coverageFactor, c.fieldOfViewYDeg(), 1.0 );
+
+    EXPECT_FALSE( eye.isUndefined() );
+}

Fwk/VizFwk/LibRender/cvfCamera.cpp

@@ -306,7 +306,14 @@ Vec3d Camera::computeFitViewEyePosition(const BoundingBox& boundingBox, const Ve
 
     cvf::Vec3d upNorm = up.getNormalized();
     cvf::Vec3d right = dir^up;
-    right.normalize();
+    if (!right.normalize())
+    {
+        // dir and up are parallel (degenerate camera orientation). Fall back to an arbitrary axis
+        // not parallel to dir to still produce a valid right vector.
+        const cvf::Vec3d& fallbackAxis = (cvf::Math::abs(dir.x()) < 0.9) ? cvf::Vec3d::X_AXIS : cvf::Vec3d::Y_AXIS;
+        right = dir^fallbackAxis;
+        right.normalize();
+    }
     cvf::Vec3d boxEyeNorm = (-dir).getNormalized();
 
     cvf::Plane planeTop;

Fwk/VizFwk/Tests/LibRender_UnitTests/cvfCamera-Test.cpp

@@ -184,6 +184,30 @@ TEST(CameraTest, FitView)
 }
 
 
+//--------------------------------------------------------------------------------------------------
+/// computeFitViewEyePosition() used to assert/abort (CVF_ASSERT in Plane::distanceToOrigin) when
+/// the view direction and up vector are parallel: dir^up then becomes a zero vector, producing an
+/// invalid (zero-normal) plane used internally. Reproduces the crash reported from
+/// caf::Viewer::zoomAll() with a degenerate camera orientation.
+//--------------------------------------------------------------------------------------------------
+TEST(CameraTest, FitViewWithParallelDirAndUpDoesNotCrash)
+{
+    Camera c;
+
+    BoundingBox bb;
+    bb.add(Vec3d(0, 0, 0));
+    bb.add(Vec3d(1, 1, 1));
+
+    Vec3d inViewDir(0, 0, 1);
+    Vec3d inUp(0, 0, 1);
+    double coverageFactor = 0.9;
+
+    Vec3d eye = Camera::computeFitViewEyePosition(bb, inViewDir, inUp, coverageFactor, c.fieldOfViewYDeg(), 1.0);
+
+    EXPECT_FALSE(eye.isUndefined());
+}
+
+
 //--------------------------------------------------------------------------------------------------
 /// 
 //--------------------------------------------------------------------------------------------------