PDAL chunked reader-only pipeline - API sample

pdal-chunk-sample.cpp

#include <chrono>
#include <iostream>
#include <memory>

#include <pdal/BufferReader.hpp>
#include <pdal/PointView.hpp>
#include <pdal/StageFactory.hpp>
#include <pdal/StageWrapper.hpp>
#include <pdal/StatsFilter.hpp>

// Common stuff.
std::unique_ptr<pdal::Reader> createReader(std::string path)
{
    pdal::StageFactory factory;
    const std::string driver(factory.inferReaderDriver(path));

    if (driver.empty())
    {
        throw std::runtime_error("No driver for " + path);
    }

    std::unique_ptr<pdal::Reader> reader(
            static_cast<pdal::Reader*>(factory.createStage(driver)));

    return reader;
}

std::chrono::high_resolution_clock::time_point now()
{
    return std::chrono::high_resolution_clock::now();
}

int msSince(const std::chrono::high_resolution_clock::time_point start)
{
    std::chrono::duration<double> d(now() - start);
    return std::chrono::duration_cast<std::chrono::milliseconds>(d).count();
}

std::size_t points(0);
double val(0);


///////////////////////////////////////////////////////////////////////////////


// Read callback functionality - default way.

auto readCb([](pdal::PointView& view, pdal::PointId id)
{
    ++points;
    val = view.getFieldAs<double>(pdal::Dimension::Id::X, id);
});

void readWithCb(std::string path)
{
    auto reader(createReader(path));

    pdal::Options options;
    options.add(pdal::Option("filename", path));
    reader->setOptions(options);

    reader->setReadCb(readCb);

    pdal::PointTable table;

    reader->prepare(table);
    reader->execute(table);
}


///////////////////////////////////////////////////////////////////////////////


// Chunked read functionality.

auto onInit([](pdal::BasePointTable&) {
    // If you need the table for anything, now's the time.  For example,
    // initializing a reprojection filter for use during onData().
});

auto onData([](pdal::PointView& view)
{
    for (std::size_t i(0); i < view.size(); ++i)
    {
        ++points;
        val = view.getFieldAs<double>(pdal::Dimension::Id::X, i);
    }
});

void readChunked(std::string path)
{
    // Optionally, customize the chunkBytes, pass your own pdal::Options, or
    // use a custom pre-populated pdal::Layout derivative.
    //
    // For point-at-a-time functionality, use a chunkBytes value of 1, since
    // this value will be rounded up to the nearest full point size.
    auto reader(createReader(path));
    reader->read(path, onInit, onData);
}


///////////////////////////////////////////////////////////////////////////////


int main()
{
    bool chunked(true);
    std::string path("/Users/connor/data/nepal/nepal.las");

    auto start(now());

    if (!chunked) readWithCb(path);
    else readChunked(path);

    int ms(msSince(start));

    std::cout << "Used " << (chunked ? "CHUNKED" : "current") << " method\n";
    std::cout << points << " points\n";
    std::cout << "Done in " << ms << " ms." << std::endl;
}