From 180d11e7f2655b1841756caf7fad7ca2c124d586 Mon Sep 17 00:00:00 2001
From: Kenneth Moreland <kmorel@sandia.gov>
Date: Thu, 18 Feb 2021 16:40:56 -0700
Subject: [PATCH] Add ImplicitFunctionGeneral

---
 vtkm/ImplicitFunction.h                     | 85 ++++++++++++++++++++-
 vtkm/cont/testing/TestingImplicitFunction.h | 26 ++++++-
 2 files changed, 108 insertions(+), 3 deletions(-)

diff --git a/vtkm/ImplicitFunction.h b/vtkm/ImplicitFunction.h
index ae0b43914..d87fe2974 100644
--- a/vtkm/ImplicitFunction.h
+++ b/vtkm/ImplicitFunction.h
@@ -14,11 +14,16 @@
 #include <vtkm/Deprecated.h>
 #include <vtkm/Math.h>
 #include <vtkm/VectorAnalysis.h>
-#include <vtkm/VirtualObjectBase.h>
+
+#include <vtkm/exec/internal/Variant.h>
 
 // For interface class only.
 #include <vtkm/cont/ExecutionAndControlObjectBase.h>
 
+#ifndef VTKM_NO_DEPRECATED_VIRTUAL
+#include <vtkm/VirtualObjectBase.h>
+#endif // VTKM_NO_DEPRECATED_VIRTUAL
+
 namespace vtkm
 {
 
@@ -778,6 +783,84 @@ private:
   Vector Center;
 };
 
+namespace detail
+{
+
+struct ImplicitFunctionValueFunctor
+{
+  template <typename ImplicitFunctionType>
+  VTKM_EXEC_CONT typename ImplicitFunctionType::Scalar operator()(
+    const ImplicitFunctionType& function,
+    const typename ImplicitFunctionType::Vector& point) const
+  {
+    return function.Value(point);
+  }
+};
+
+struct ImplicitFunctionGradientFunctor
+{
+  template <typename ImplicitFunctionType>
+  VTKM_EXEC_CONT typename ImplicitFunctionType::Vector operator()(
+    const ImplicitFunctionType& function,
+    const typename ImplicitFunctionType::Vector& point) const
+  {
+    return function.Gradient(point);
+  }
+};
+
+} // namespace detail
+
+template <typename... ImplicitFunctionTypes>
+class ImplicitFunctionMultiplexer
+  : public vtkm::internal::ImplicitFunctionBase<
+      ImplicitFunctionMultiplexer<ImplicitFunctionTypes...>>
+{
+  vtkm::exec::internal::Variant<ImplicitFunctionTypes...> Variant;
+
+  using Superclass =
+    vtkm::internal::ImplicitFunctionBase<ImplicitFunctionMultiplexer<ImplicitFunctionTypes...>>;
+
+public:
+  using Scalar = typename Superclass::Scalar;
+  using Vector = typename Superclass::Vector;
+
+  VTKM_EXEC_CONT ImplicitFunctionMultiplexer() = default;
+
+  template <typename FunctionType>
+  VTKM_EXEC_CONT ImplicitFunctionMultiplexer(
+    const vtkm::internal::ImplicitFunctionBase<FunctionType>& function)
+    : Variant(reinterpret_cast<const FunctionType&>(function))
+  {
+  }
+
+  VTKM_EXEC_CONT Scalar Value(const Vector& point) const
+  {
+    return this->Variant.CastAndCall(detail::ImplicitFunctionValueFunctor{}, point);
+  }
+
+  VTKM_EXEC_CONT Vector Gradient(const Vector& point) const
+  {
+    return this->Variant.CastAndCall(detail::ImplicitFunctionGradientFunctor{}, point);
+  }
+};
+
+class ImplicitFunctionGeneral
+  : public vtkm::ImplicitFunctionMultiplexer<vtkm::Box,
+                                             vtkm::Cylinder,
+                                             vtkm::Frustum,
+                                             vtkm::Plane,
+                                             vtkm::Sphere>
+{
+  using Superclass = vtkm::ImplicitFunctionMultiplexer<vtkm::Box,
+                                                       vtkm::Cylinder,
+                                                       vtkm::Frustum,
+                                                       vtkm::Plane,
+                                                       vtkm::Sphere>;
+
+public:
+  using Superclass::Superclass;
+};
+
 } // namespace vtkm
 
 #endif //vtk_m_ImplicitFunction_h
diff --git a/vtkm/cont/testing/TestingImplicitFunction.h b/vtkm/cont/testing/TestingImplicitFunction.h
index 7841ffccb..c6efdfc9f 100644
--- a/vtkm/cont/testing/TestingImplicitFunction.h
+++ b/vtkm/cont/testing/TestingImplicitFunction.h
@@ -131,10 +131,32 @@ private:
       VTKM_TEST_ASSERT(test_equal_ArrayHandles(values, expectedValuesArray));
       VTKM_TEST_ASSERT(test_equal_ArrayHandles(gradients, expectedGradientsArray));
     }
-  }
-  VTKM_DEPRECATED_SUPPRESS_END
+    VTKM_DEPRECATED_SUPPRESS_END
 #endif //!VTKM_NO_DEPRECATED_VIRTUAL
 
+    {
+      vtkm::ImplicitFunctionMultiplexer<ImplicitFunctorType> functionChoose(function);
+      vtkm::cont::ArrayHandle<vtkm::FloatDefault> values;
+      vtkm::cont::ArrayHandle<vtkm::Vec<vtkm::FloatDefault, 3>> gradients;
+      implicit_function_detail::EvaluateOnCoordinates(
+        this->Input.GetCoordinateSystem(0), functionChoose, values, gradients, device);
+
+      VTKM_TEST_ASSERT(test_equal_ArrayHandles(values, expectedValuesArray));
+      VTKM_TEST_ASSERT(test_equal_ArrayHandles(gradients, expectedGradientsArray));
+    }
+
+    {
+      vtkm::ImplicitFunctionGeneral functionChoose(function);
+      vtkm::cont::ArrayHandle<vtkm::FloatDefault> values;
+      vtkm::cont::ArrayHandle<vtkm::Vec<vtkm::FloatDefault, 3>> gradients;
+      implicit_function_detail::EvaluateOnCoordinates(
+        this->Input.GetCoordinateSystem(0), functionChoose, values, gradients, device);
+
+      VTKM_TEST_ASSERT(test_equal_ArrayHandles(values, expectedValuesArray));
+      VTKM_TEST_ASSERT(test_equal_ArrayHandles(gradients, expectedGradientsArray));
+    }
+  }
+
   template <typename DeviceAdapter>
   void TestBox(DeviceAdapter device)
   {