| RDB 2

rdb-example-03-select-points.cpp
/*
*******************************************************************************
*
* Copyright 2026 RIEGL Laser Measurement Systems
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* SPDX-License-Identifier: Apache-2.0
*
*******************************************************************************
*/
/*!
*******************************************************************************
*
* \file rdb-example-03-select-points.cpp
* \author RIEGL LMS GmbH, Austria
* \brief RDB example 3: Select points
* \version 2015-10-14/AW: Initial version
* \version 2018-07-10/AW: Use new bindBuffer() instead of bind() function
* \version 2023-06-12/AW: Use #if instead of ternary operator in select()
*
* This example shows how to open an existing database and query some points.
* This example is based on the database of rdb-example-1-create-database.
*
* Build instructions see "interface/cpp/riegl/README.TXT".
*
*******************************************************************************
*/
#include <array>
#include <vector>
#include <cstdint>
#include <iostream>
#include <exception>
#include <riegl/rdb.hpp>
#include <riegl/rdb/default.hpp>
int main()
{
try
{
// New RDB library context
riegl::rdb::Context context;
// Access existing database
riegl::rdb::Pointcloud rdb(context);
riegl::rdb::pointcloud::OpenSettings settings;
rdb.open("pointcloud.rdbx", settings);
// No transaction required here as we are only reading
// points from database and are not going to modify them.
// Prepare point attribute buffers
const uint32_t BUFFER_SIZE = 10000;
std::vector< uint64_t > bufferPointNumber(BUFFER_SIZE);
std::vector< std::array<double, 3> > bufferCoordinates(BUFFER_SIZE);
std::vector< float > bufferAmplitude (BUFFER_SIZE);
std::vector< float > bufferReflectance(BUFFER_SIZE);
std::vector< std::array<uint8_t, 4> > bufferTrueColor (BUFFER_SIZE);
std::vector< uint16_t > bufferPointClass (BUFFER_SIZE);
// Start new select query to read...
riegl::rdb::pointcloud::QuerySelect select = rdb.select(
#if 0
// ...all points (empty filter string):
""
#else
// ...or just some specific points:
"(riegl.class == 3) && (riegl.xyz[2] > 5.0)"
#endif
);
// Tell select query where to store the data
using namespace riegl::rdb::pointcloud;
select.bindBuffer(RDB_RIEGL_ID, bufferPointNumber);
select.bindBuffer(RDB_RIEGL_XYZ, bufferCoordinates);
select.bindBuffer(RDB_RIEGL_AMPLITUDE, bufferAmplitude);
select.bindBuffer(RDB_RIEGL_REFLECTANCE, bufferReflectance);
select.bindBuffer(RDB_RIEGL_RGBA, bufferTrueColor);
select.bindBuffer(RDB_RIEGL_CLASS, bufferPointClass);
// Read and process all points block-wise
while (const uint32_t count = select.next(BUFFER_SIZE))
{
// Print points to output stream
for (uint32_t i = 0; i < count; i++)
{
std::cout << bufferPointNumber[i] << ","
<< bufferCoordinates[i][0] << ","
<< bufferCoordinates[i][1] << ","
<< bufferCoordinates[i][2] << ","
<< bufferAmplitude [i] << ","
<< bufferReflectance[i] << ","
<< int(bufferTrueColor [i][0]) << ","
<< int(bufferTrueColor [i][1]) << ","
<< int(bufferTrueColor [i][2]) << ","
<< bufferPointClass [i] << std::endl;
}
}
// Success
return 0;
}
catch(const riegl::rdb::Error &error)
{
std::cerr << error.what() << " (" << error.details() << ")" << std::endl;
return 1; // error
}
catch(const std::exception &error)
{
std::cerr << error.what() << std::endl;
return 1; // error
}
}