From fd613f2c84d770f969074a668324545debf05728 Mon Sep 17 00:00:00 2001
From: Dave Pugmire <dpugmire@gmail.com>
Date: Thu, 16 Feb 2023 21:55:46 -0500
Subject: [PATCH] Fixes to rendering. Attempt at getting VR

---
 vtkm/rendering/View3D.cxx                     | 78 ++++++++++++++++++-
 .../testing/UnitTestImageCompositing.cxx      | 54 ++++++++++++-
 2 files changed, 128 insertions(+), 4 deletions(-)

diff --git a/vtkm/rendering/View3D.cxx b/vtkm/rendering/View3D.cxx
index bc1998cd4..d1a8167dd 100644
--- a/vtkm/rendering/View3D.cxx
+++ b/vtkm/rendering/View3D.cxx
@@ -11,6 +11,12 @@
 #include <vtkm/cont/EnvironmentTracker.h>
 #include <vtkm/rendering/View3D.h>
 
+#ifdef VTKM_ENABLE_MPI
+#include <mpi.h>
+#include <vtkm/thirdparty/diy/diy.h>
+#include <vtkm/thirdparty/diy/mpi-cast.h>
+#endif
+
 namespace vtkm
 {
 namespace rendering
@@ -49,6 +55,8 @@ void View3D::Paint()
     return;
 
   this->Compositor.SetCompositeMode(vtkm::rendering::compositing::Compositor::Z_BUFFER_SURFACE);
+  //volume render
+  this->Compositor.SetCompositeMode(vtkm::rendering::compositing::Compositor::VIS_ORDER_BLEND);
   /*
   auto colors = (this->GetCanvas().GetColorBuffer().WritePortal().GetArray())[0][0];
   auto depths = (this->GetCanvas().GetDepthBuffer().WritePortal().GetArray());
@@ -82,13 +90,46 @@ void View3D::Paint()
 
 void View3D::RenderScreenAnnotations()
 {
-  if (this->GetScene().GetNumberOfActors() > 0)
+  vtkm::Range scalarRange;
+
+  int numActors = this->GetScene().GetNumberOfActors();
+  if (numActors > 0)
+    scalarRange = this->GetScene().GetActor(0).GetScalarRange();
+
+  int totNumActors = numActors;
+
+  /*
+#ifdef VTKM_ENABLE_MPI
+  auto comm = vtkm::cont::EnvironmentTracker::GetCommunicator();
+
+  vtkm::Float64 minVal = scalarRange.Min, maxVal = scalarRange.Max;
+
+  MPI_Comm mpiComm = vtkmdiy::mpi::mpi_cast(comm.handle());
+  int totNumActors = 0;
+  vtkm::Float64 minVal_res = 0, maxVal_res = 0;
+  MPI_Reduce(&numActors, &totNumActors, 1, MPI_INT, MPI_SUM, 0, mpiComm);
+  MPI_Reduce(&minVal, &minVal_res, 1, MPI_DOUBLE, MPI_MIN, 0, mpiComm);
+  MPI_Reduce(&maxVal, &maxVal_res, 1, MPI_DOUBLE, MPI_MAX, 0, mpiComm);
+  if (comm.rank() != 0)
+    return;
+
+  scalarRange.Min = minVal_res;
+  scalarRange.Max = maxVal_res;
+#endif
+
+  std::cout<<"totNumActors= "<<totNumActors<<" range= "<<scalarRange<<std::endl;
+
+  //DRP
+  //This assumes that rank 0 has an actor!!
+  */
+
+  if (totNumActors > 0)
   {
     this->GetCanvas().BeginTextRenderingBatch();
     this->GetWorldAnnotator().BeginLineRenderingBatch();
     //this->ColorBarAnnotation.SetAxisColor(vtkm::rendering::Color(1,1,1));
     this->ColorBarAnnotation.SetFieldName(this->GetScene().GetActor(0).GetScalarField().GetName());
-    this->ColorBarAnnotation.SetRange(this->GetScene().GetActor(0).GetScalarRange(), 5);
+    this->ColorBarAnnotation.SetRange(scalarRange, 5);
     this->ColorBarAnnotation.SetColorTable(this->GetScene().GetActor(0).GetColorTable());
     this->ColorBarAnnotation.Render(
       this->GetCamera(), this->GetWorldAnnotator(), this->GetCanvas());
@@ -99,8 +140,39 @@ void View3D::RenderScreenAnnotations()
 
 void View3D::RenderWorldAnnotations()
 {
-  this->GetCanvas().BeginTextRenderingBatch();
   vtkm::Bounds bounds = this->GetScene().GetSpatialBounds();
+
+#ifdef VTKM_ENABLE_MPI
+  //For parallel, get the collective bounds.
+  auto comm = vtkm::cont::EnvironmentTracker::GetCommunicator();
+
+  vtkm::Float64 mins[3], maxs[3], mins_res[3], maxs_res[3];
+  mins[0] = bounds.X.Min;
+  mins[1] = bounds.Y.Min;
+  mins[2] = bounds.Z.Min;
+  maxs[0] = bounds.X.Max;
+  maxs[1] = bounds.Y.Max;
+  maxs[2] = bounds.Z.Max;
+
+  //DRP
+  //what if a scene has NO actors??
+
+  MPI_Comm mpiComm = vtkmdiy::mpi::mpi_cast(comm.handle());
+  MPI_Reduce(mins, mins_res, 3, MPI_DOUBLE, MPI_MIN, 0, mpiComm);
+  MPI_Reduce(maxs, maxs_res, 3, MPI_DOUBLE, MPI_MAX, 0, mpiComm);
+  if (comm.rank() != 0)
+    return;
+
+  bounds.X.Min = mins_res[0];
+  bounds.Y.Min = mins_res[1];
+  bounds.Z.Min = mins_res[2];
+  bounds.X.Max = maxs_res[0];
+  bounds.Y.Max = maxs_res[1];
+  bounds.Z.Max = maxs_res[2];
+
+#endif
+
+  this->GetCanvas().BeginTextRenderingBatch();
   vtkm::Float64 xmin = bounds.X.Min, xmax = bounds.X.Max;
   vtkm::Float64 ymin = bounds.Y.Min, ymax = bounds.Y.Max;
   vtkm::Float64 zmin = bounds.Z.Min, zmax = bounds.Z.Max;
diff --git a/vtkm/rendering/testing/UnitTestImageCompositing.cxx b/vtkm/rendering/testing/UnitTestImageCompositing.cxx
index 9616803b9..8880fe320 100644
--- a/vtkm/rendering/testing/UnitTestImageCompositing.cxx
+++ b/vtkm/rendering/testing/UnitTestImageCompositing.cxx
@@ -176,10 +176,62 @@ void TestRenderComposite()
   */
 }
 
+void TestVolumeRenderComposite()
+{
+  using vtkm::rendering::CanvasRayTracer;
+  using vtkm::rendering::MapperVolume;
+
+  auto comm = vtkm::cont::EnvironmentTracker::GetCommunicator();
+
+  int numBlocks = comm.size() * 1;
+  int rank = comm.rank();
+  int dsPerRank = 1;
+
+  vtkm::rendering::Camera camera;
+  camera.SetLookAt(vtkm::Vec3f_32(1.0, 0.5, 0.5));
+  camera.SetViewUp(vtkm::make_Vec(0.f, 1.f, 0.f));
+  camera.SetClippingRange(1.f, 10.f);
+  camera.SetFieldOfView(60.f);
+  camera.SetPosition(vtkm::Vec3f_32(-2, 1.75, 1.75));
+  vtkm::cont::ColorTable colorTable("inferno");
+
+  colorTable.AddPointAlpha(0.0, .01f);
+  colorTable.AddPointAlpha(1.0, .01f);
+
+  // Background color:
+  vtkm::rendering::Color bg(0.2f, 0.2f, 0.2f, 1.0f);
+  vtkm::rendering::Scene scene;
+  int width = 512, height = 512;
+  CanvasRayTracer canvas(width, height);
+
+  for (int i = 0; i < dsPerRank; i++)
+  {
+    //Create a sequence of datasets along the X direction.
+    std::string fieldName = "tangle";
+    vtkm::source::Tangle tangle;
+    vtkm::Vec3f pt(rank * dsPerRank + i, 0, 0);
+    if (rank == 1)
+      std::cout << "PT= " << pt << std::endl;
+    tangle.SetPointDimensions({ 50, 50, 50 });
+    tangle.SetOrigin(pt);
+    vtkm::cont::DataSet ds = tangle.Execute();
+
+    vtkm::rendering::Actor actor(
+      ds.GetCellSet(), ds.GetCoordinateSystem(), ds.GetField(fieldName), colorTable);
+    scene.AddActor(actor);
+  }
+
+  vtkm::rendering::View3D view(scene, MapperVolume(), canvas, camera, bg);
+  view.Paint();
+
+  canvas.SaveAs("result.png");
+}
+
 void RenderTests()
 {
   //  TestImageComposite();
-  TestRenderComposite();
+  //TestRenderComposite();
+  TestVolumeRenderComposite();
 }
 
 } //namespace