Interop now works when device adapter isn't known.

Additionally the Interop calls now pass the ArrayHandle by const ref.

vtkm/interop/TransferToOpenGL.h

@@ -46,7 +46,8 @@ struct TransferToOpenGL
                             BufferState& state) const
   {
     vtkm::interop::internal::TransferToOpenGL<ValueType, DeviceAdapterTag> toGL(state);
-    return toGL.Transfer(handle);
+    toGL.Transfer(handle);
+    return true;
   }
 };
 }
@@ -64,7 +65,7 @@ struct TransferToOpenGL
 ///
 ///
 template <typename ValueType, class StorageTag, class DeviceAdapterTag>
-VTKM_CONT void TransferToOpenGL(vtkm::cont::ArrayHandle<ValueType, StorageTag> handle,
+VTKM_CONT void TransferToOpenGL(const vtkm::cont::ArrayHandle<ValueType, StorageTag>& handle,
                                 BufferState& state,
                                 DeviceAdapterTag)
 {
@@ -86,17 +87,17 @@ VTKM_CONT void TransferToOpenGL(vtkm::cont::ArrayHandle<ValueType, StorageTag> h
 /// This function will throw exceptions if the transfer wasn't possible
 ///
 template <typename ValueType, typename StorageTag>
-VTKM_CONT void TransferToOpenGL(vtkm::cont::ArrayHandle<ValueType, StorageTag> handle,
+VTKM_CONT void TransferToOpenGL(const vtkm::cont::ArrayHandle<ValueType, StorageTag>& handle,
                                 BufferState& state)
 {
 
   vtkm::cont::DeviceAdapterId devId = handle.GetDeviceAdapterId();
-  bool success = vtkm::cont::TryExecuteOnDevice(devId, TransferToOpenGL, handle, state);
+  bool success = vtkm::cont::TryExecuteOnDevice(devId, detail::TransferToOpenGL{}, handle, state);
   if (!success)
   {
     //Generally we are here because the devId is undefined
     //or for some reason the last executed device is now disabled
-    success = vtkm::cont::TryExecute(TransferToOpenGL, handle, state);
+    success = vtkm::cont::TryExecute(detail::TransferToOpenGL{}, handle, state);
   }
   if (!success)
   {

vtkm/interop/cuda/internal/TransferToOpenGL.h

@@ -24,7 +24,6 @@
 #include <vtkm/cont/ErrorExecution.h>
 
 #include <vtkm/cont/cuda/internal/DeviceAdapterTagCuda.h>
-#include <vtkm/cont/cuda/internal/MakeThrustIterator.h>
 
 #include <vtkm/interop/internal/TransferToOpenGL.h>
 
@@ -157,7 +156,7 @@ public:
   }
 
   template <typename StorageTag>
-  VTKM_CONT void Transfer(vtkm::cont::ArrayHandle<ValueType, StorageTag>& handle) const
+  VTKM_CONT void Transfer(const vtkm::cont::ArrayHandle<ValueType, StorageTag>& handle) const
   {
     //make a buffer for the handle if the user has forgotten too
     if (!glIsBuffer(*this->State.GetHandle()))
@@ -192,20 +191,10 @@ public:
     this->Resource->Map();
 
     ValueType* beginPointer = this->Resource->GetMappedPoiner<ValueType>(size);
+    auto deviceMemory = vtkm::cont::make_ArrayHandle(beginPointer, size);
 
-    //get the device pointers
-    auto portal = handle.PrepareForInput(DeviceAdapterTag());
-
-    //Copy the data into memory that opengl owns, since we can't
-    //give memory from cuda to opengl
-
-    //Perhaps a direct call to thrust copy should be wrapped in a vtkm
-    //compatble function
-    ::thrust::copy(ThrustCudaPolicyPerThread,
-                   vtkm::cont::cuda::internal::IteratorBegin(portal),
-                   vtkm::cont::cuda::internal::IteratorEnd(portal),
-                   thrust::cuda::pointer<ValueType>(beginPointer));
-    cudaStreamSynchronize(cudaStreamPerThread);
+    //Do a device to device memory copy
+    vtkm::cont::DeviceAdapterAlgorithm<DeviceAdapterTag>::Copy(handle, deviceMemory);
 
     //unmap the resource
     this->Resource->UnMap();

vtkm/interop/internal/TransferToOpenGL.h

@@ -95,7 +95,7 @@ namespace detail
 {
 
 template <class ValueType, class StorageTag, class DeviceAdapterTag>
-VTKM_CONT void CopyFromHandle(vtkm::cont::ArrayHandle<ValueType, StorageTag>& handle,
+VTKM_CONT void CopyFromHandle(const vtkm::cont::ArrayHandle<ValueType, StorageTag>& handle,
                               vtkm::interop::BufferState& state,
                               DeviceAdapterTag)
 {
@@ -145,7 +145,7 @@ VTKM_CONT void CopyFromHandle(vtkm::cont::ArrayHandle<ValueType, StorageTag>& ha
 
 template <class ValueType, class DeviceAdapterTag>
 VTKM_CONT void CopyFromHandle(
-  vtkm::cont::ArrayHandle<ValueType, vtkm::cont::StorageTagBasic>& handle,
+  const vtkm::cont::ArrayHandle<ValueType, vtkm::cont::StorageTagBasic>& handle,
   vtkm::interop::BufferState& state,
   DeviceAdapterTag)
 {
@@ -196,7 +196,7 @@ public:
   }
 
   template <typename StorageTag>
-  VTKM_CONT void Transfer(vtkm::cont::ArrayHandle<ValueType, StorageTag>& handle) const
+  VTKM_CONT void Transfer(const vtkm::cont::ArrayHandle<ValueType, StorageTag>& handle) const
   {
     //make a buffer for the handle if the user has forgotten too
     if (!glIsBuffer(*this->State.GetHandle()))