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tobre1tobre1
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Calculate visibility on LS grid points (#108)
* Add CalculateVisibilities function * Fix typo * Fix iterator template parameter * Default params * Delete visibility scalar data if it already exists * Visibilities calculated in any direction * Change visibility label * Add visibility test and parallelize * Fixed visibility calculation * Scale direction vector by grid delta * Fix typo * Cast grid delta to correct type --------- Co-authored-by: = <=>
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‎include/viennals/lsCalculateVisibilities.hpp

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#pragma once
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#include <lsDomain.hpp>
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#include <vcVectorUtil.hpp>
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namespace viennals {
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using namespace viennacore;
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template <class NumericType, int D> class CalculateVisibilities {
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SmartPointer<Domain<NumericType, D>> levelSet;
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Vec3D<NumericType> direction;
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const NumericType epsilon = static_cast<NumericType>(1e-6);
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const std::string visibilitiesLabel;
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public:
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CalculateVisibilities(
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const SmartPointer<Domain<NumericType, D>> &passedLevelSet,
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const Vec3D<NumericType> passedDirection,
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const std::string label = "Visibilities")
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: levelSet(passedLevelSet), direction(passedDirection),
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visibilitiesLabel(std::move(label)) {}
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void apply() {
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auto &domain = levelSet->getDomain();
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auto &grid = levelSet->getGrid();
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// *** Determine extents of domain ***
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Vec3D<NumericType> minDefinedPoint;
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Vec3D<NumericType> maxDefinedPoint;
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// Initialize with extreme values
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for (int i = 0; i < D; ++i) {
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minDefinedPoint[i] = std::numeric_limits<NumericType>::max();
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maxDefinedPoint[i] = std::numeric_limits<NumericType>::lowest();
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}
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// Iterate through all defined points in the domain
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for (hrleSparseIterator<typename Domain<NumericType, D>::DomainType> it(
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domain);
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!it.isFinished(); it.next()) {
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if (!it.isDefined())
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continue; // Skip undefined points
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// Get the coordinate of the current point
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auto point = it.getStartIndices();
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for (int i = 0; i < D; ++i) {
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// Compare to update min and max defined points
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NumericType coord = point[i]; // * grid.getGridDelta();
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minDefinedPoint[i] = std::min(minDefinedPoint[i], coord);
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maxDefinedPoint[i] = std::max(maxDefinedPoint[i], coord);
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}
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}
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//****************************
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// Invert the vector
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auto dir = Normalize(Inv(direction)) *
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static_cast<NumericType>(domain.getGrid().getGridDelta());
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auto numDefinedPoints = domain.getNumberOfPoints();
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std::vector<NumericType> visibilities(numDefinedPoints);
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#pragma omp parallel num_threads(levelSet->getNumberOfSegments())
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{
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int p = 0;
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#ifdef _OPENMP
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p = omp_get_thread_num();
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#endif
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hrleVectorType<hrleIndexType, D> startVector =
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(p == 0) ? grid.getMinGridPoint() : domain.getSegmentation()[p - 1];
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hrleVectorType<hrleIndexType, D> endVector =
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(p != static_cast<int>(domain.getNumberOfSegments() - 1))
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? domain.getSegmentation()[p]
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: grid.incrementIndices(grid.getMaxGridPoint());
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// Calculate the starting index for the visibility vector
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hrleSizeType id = 0;
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for (int i = 0; i < p; ++i) {
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id += domain.getDomainSegment(i).getNumberOfPoints();
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}
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for (hrleSparseIterator<typename Domain<NumericType, D>::DomainType> it(
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domain, startVector);
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it.getStartIndices() < endVector; ++it) {
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if (!it.isDefined())
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continue;
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// Starting position of the point
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Vec3D<NumericType> currentPos;
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for (int i = 0; i < D; ++i) {
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currentPos[i] = it.getStartIndices(i);
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}
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// Start tracing the ray
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NumericType minLevelSetValue =
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it.getValue(); // Starting level set value
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Vec3D<NumericType> rayPos = currentPos;
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bool visibility = true;
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while (1) {
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// Update the ray position
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for (int i = 0; i < D; ++i) {
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rayPos[i] += dir[i];
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}
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// Determine the nearest grid cell (round to nearest index)
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Vec3D<hrleIndexType> nearestCell;
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for (int i = 0; i < D; ++i) {
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nearestCell[i] = static_cast<hrleIndexType>(rayPos[i]);
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}
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// // Before adding a cell, check if it's already visited
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// if (std::find(visitedCells.begin(), visitedCells.end(),
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// nearestCell)
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// == visitedCells.end()) {
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// visitedCells.push_back(nearestCell);
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// }
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// Check if the nearest cell is within bounds
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bool outOfBounds = false;
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for (int i = 0; i < D; ++i) {
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if (nearestCell[i] < minDefinedPoint[i] ||
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nearestCell[i] > maxDefinedPoint[i]) {
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outOfBounds = true;
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break;
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}
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}
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if (outOfBounds) {
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break; // Ray is outside the grid
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}
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// Access the level set value at the nearest cell
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NumericType neighborValue = std::numeric_limits<NumericType>::max();
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hrleSparseIterator<typename Domain<NumericType, D>::DomainType>
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neighborIt(domain);
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neighborIt.goToIndices(nearestCell);
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neighborValue = neighborIt.getValue();
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// Update the minimum value encountered
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if (neighborValue < minLevelSetValue) {
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visibility = false;
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break;
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}
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}
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// Update visibility for this point
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visibilities[id++] = visibility ? 1.0 : 0.0;
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}
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}
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auto &pointData = levelSet->getPointData();
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// delete if already exists
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if (int i = pointData.getScalarDataIndex(visibilitiesLabel); i != -1) {
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pointData.eraseScalarData(i);
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}
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pointData.insertNextScalarData(visibilities, visibilitiesLabel);
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}
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};
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} // namespace viennals

‎tests/Visibility/CMakeLists.txt

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project(Visibility LANGUAGES CXX)
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add_executable(${PROJECT_NAME} "${PROJECT_NAME}.cpp")
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target_link_libraries(${PROJECT_NAME} PRIVATE ViennaLS)
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add_dependencies(ViennaLS_Tests ${PROJECT_NAME})
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add_test(NAME ${PROJECT_NAME} COMMAND $<TARGET_FILE:${PROJECT_NAME}>)

‎tests/Visibility/Visibility.cpp

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#include <chrono>
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#include <iostream>
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#include <lsCalculateVisibilities.hpp>
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#include <lsDomain.hpp>
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#include <lsExpand.hpp>
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#include <lsMakeGeometry.hpp>
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#include <lsToMesh.hpp>
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#include <lsVTKWriter.hpp>
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namespace ls = viennals;
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int main() {
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constexpr int D = 2;
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double gridDelta = 0.4;
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auto sphere1 = ls::SmartPointer<ls::Domain<double, D>>::New(
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gridDelta); //, boundaryCons);
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double origin[3] = {5., 0., 0.};
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double radius = 7.3;
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ls::MakeGeometry<double, D>(
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sphere1, ls::SmartPointer<ls::Sphere<double, D>>::New(origin, radius))
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.apply();
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ls::Expand<double, D>(sphere1, 5).apply();
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ls::CalculateVisibilities<double, D>(sphere1, ls::Vec3D<double>{0., -1.0, 0.})
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.apply();
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auto mesh = ls::SmartPointer<ls::Mesh<>>::New();
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ls::ToMesh<double, D>(sphere1, mesh).apply();
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ls::VTKWriter<double>(mesh, "visibility_test.vtp").apply();
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return 0;
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}

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