imstkVTKHexahedralMeshRenderDelegate.cpp

/*
** This file is part of the Interactive Medical Simulation Toolkit (iMSTK)
** iMSTK is distributed under the Apache License, Version 2.0.
** See accompanying NOTICE for details.
*/

#include "imstkVTKHexahedralMeshRenderDelegate.h"
#include "imstkHexahedralMesh.h"
#include "imstkVisualModel.h"
#include "imstkGeometryUtilities.h"
#include "imstkRenderMaterial.h"

#include <vtkActor.h>
#include <vtkDataSetMapper.h>
#include <vtkDoubleArray.h>
#include <vtkUnstructuredGrid.h>
#include <vtkPointData.h>
#include <vtkTransform.h>

namespace imstk
{
VTKHexahedralMeshRenderDelegate::VTKHexahedralMeshRenderDelegate() :
    m_mesh(vtkSmartPointer<vtkUnstructuredGrid>::New()),
    m_mappedVertexArray(vtkSmartPointer<vtkDoubleArray>::New())
{
}

void
VTKHexahedralMeshRenderDelegate::init()
{
    auto geometry = std::dynamic_pointer_cast<HexahedralMesh>(m_visualModel->getGeometry());
    CHECK(geometry != nullptr) << "VTKHexahedralMeshRenderDelegate only works with HexahedralMesh geometry";
    m_vertices = geometry->getVertexPositions();
    m_indices  = geometry->getCells();

    // Map vertices
    {
        m_mappedVertexArray = vtkDoubleArray::SafeDownCast(GeometryUtils::coupleVtkDataArray(m_vertices));
        auto points = vtkSmartPointer<vtkPoints>::New();
        points->SetNumberOfPoints(geometry->getNumVertices());
        points->SetData(m_mappedVertexArray);
        m_mesh->SetPoints(points);
    }

    // Map vertex scalars if it has them
    if (geometry->getVertexScalars() != nullptr)
    {
        m_mappedVertexScalarArray = GeometryUtils::coupleVtkDataArray(geometry->getVertexScalars());
        m_mesh->GetPointData()->SetScalars(m_mappedVertexScalarArray);
    }

    // Map indices to VTK cell data (copied, not coupled)
    {
        m_cellArray = vtkSmartPointer<vtkCellArray>::New();
        vtkIdType cell[8];
        for (const auto& t : *m_indices)
        {
            for (size_t i = 0; i < 8; ++i)
            {
                cell[i] = t[i];
            }
            m_cellArray->InsertNextCell(8, cell);
        }
        m_mesh->SetCells(VTK_HEXAHEDRON, m_cellArray);
    }

    // When geometry is modified, update data source, mostly for when an entirely new array/buffer was set
    queueConnect<Event>(geometry, &Geometry::modified,
        std::static_pointer_cast<VTKHexahedralMeshRenderDelegate>(shared_from_this()),
        &VTKHexahedralMeshRenderDelegate::geometryModified);

    // When the vertex buffer internals are modified, ie: a single or N elements
    queueConnect<Event>(geometry->getVertexPositions(), &VecDataArray<double, 3>::modified,
        std::static_pointer_cast<VTKHexahedralMeshRenderDelegate>(shared_from_this()),
        &VTKHexahedralMeshRenderDelegate::vertexDataModified);

    // Setup mapper
    {
        vtkNew<vtkDataSetMapper> mapper;
        mapper->SetInputData(m_mesh);
        vtkNew<vtkActor> actor;
        actor->SetMapper(mapper);
        actor->SetUserTransform(m_transform);
        m_actor  = actor;
        m_mapper = mapper;
    }

    update();
    updateRenderProperties();
}

void
VTKHexahedralMeshRenderDelegate::processEvents()
{
    // Custom handling of events
    std::shared_ptr<HexahedralMesh>          geom     = std::dynamic_pointer_cast<HexahedralMesh>(m_visualModel->getGeometry());
    std::shared_ptr<VecDataArray<double, 3>> vertices = geom->getVertexPositions();

    // Only use the most recent event from respective sender
    std::list<Command> cmds;
    bool               contains[4] = { false, false, false, false };
    rforeachEvent([&](Command cmd)
        {
            if (cmd.m_event->m_sender == m_visualModel.get() && !contains[0])
            {
                cmds.push_back(cmd);
                contains[0] = true;
            }
            else if (cmd.m_event->m_sender == m_material.get() && !contains[1])
            {
                cmds.push_back(cmd);
                contains[1] = true;
            }
            else if (cmd.m_event->m_sender == geom.get() && !contains[2])
            {
                cmds.push_back(cmd);
                contains[2] = true;
            }
            else if (cmd.m_event->m_sender == vertices.get() && !contains[3])
            {
                cmds.push_back(cmd);
                contains[3] = true;
            }
        });

    // Now do each event in order recieved
    for (std::list<Command>::reverse_iterator i = cmds.rbegin(); i != cmds.rend(); i++)
    {
        i->invoke();
    }
}

void
VTKHexahedralMeshRenderDelegate::geometryModified(Event* imstkNotUsed(e))
{
    auto geometry = std::static_pointer_cast<HexahedralMesh>(m_visualModel->getGeometry());

    // Test if the vertex buffer changed
    if (m_vertices != geometry->getVertexPositions())
    {
        //printf("Vertex data swapped\n");
        m_vertices = geometry->getVertexPositions();
        {
            // Update the pointer of the coupled array
            m_mappedVertexArray->SetNumberOfComponents(3);
            m_mappedVertexArray->SetArray(reinterpret_cast<double*>(m_vertices->getPointer()), m_vertices->size() * 3, 1);
        }
    }
    m_mappedVertexArray->Modified();

    // Test if the index buffer changed
    if (m_indices != geometry->getCells())
    {
        //printf("Index data swapped\n");
        m_indices = geometry->getCells();
        {
            // Copy cells
            m_cellArray->Reset();
            vtkIdType cell[8];
            for (const auto& t : *m_indices)
            {
                for (size_t i = 0; i < 8; ++i)
                {
                    cell[i] = t[i];
                }
                m_cellArray->InsertNextCell(8, cell);
            }
            m_mesh->SetCells(VTK_TETRA, m_cellArray);
            m_cellArray->Modified();
        }
    }
}

void
VTKHexahedralMeshRenderDelegate::vertexDataModified(Event* imstkNotUsed(e))
{
    auto geometry = std::static_pointer_cast<HexahedralMesh>(m_visualModel->getGeometry());
    m_vertices = geometry->getVertexPositions();
    if (m_vertices->getVoidPointer() != m_mappedVertexArray->GetVoidPointer(0))
    {
        m_mappedVertexArray->SetNumberOfComponents(3);
        m_mappedVertexArray->SetArray(reinterpret_cast<double*>(m_vertices->getPointer()), m_vertices->size() * 3, 1);
    }
    m_mappedVertexArray->Modified();
}
} // namespace imstk