How to compile RealSense examples? - c++

Question

I have cloned the RealSense official source code from their Github page. There was a problem when I was compiling the example align-advanced. The following is my terminal situation:
$ cd ~/librealsense/examples/align-advanced
$ mkdir build
$ cd build
~/librealsense/examples/align-advanced/build$ cmake ..
-- The C compiler identification is GNU 7.5.0
-- The CXX compiler identification is GNU 7.5.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Configuring done
-- Generating done
-- Build files have been written to: /home/automation/librealsense/examples/align-advanced/build
~/librealsense/examples/align-advanced/build$ make
~/librealsense/examples/align-advanced/build$
As you can see, nothing happens after typing make, and no executable files appear in the build folder.
The contents of offical CMakeList.txt are as follows:
# License: Apache 2.0. See LICENSE file in root directory.
# Copyright(c) 2019 Intel Corporation. All Rights Reserved.
# minimum required cmake version: 3.1.0
cmake_minimum_required(VERSION 3.1.0)
project(RealsenseExamplesAlignAdvanced)
if(BUILD_GRAPHICAL_EXAMPLES)
add_executable(rs-align-advanced rs-align-advanced.cpp ../../third-party/imgui/imgui.cpp ../../third-party/imgui/imgui_draw.cpp ../../third-party/imgui/imgui_impl_glfw.cpp)
set_property(TARGET rs-align-advanced PROPERTY CXX_STANDARD 11)
target_link_libraries(rs-align-advanced ${DEPENDENCIES})
include_directories(rs-align-advanced ../../common ../../third-party/imgui)
set_target_properties (rs-align-advanced PROPERTIES FOLDER Examples)
install(TARGETS rs-align-advanced RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
endif()
What is the problem?

Answer 1

CMake was intended to be run from the top-level directory of the entire project. This is a general CMake rule-of-thumb; it typically applies to any CMake-based project, not only RealSense.
If you want to enable the compilation of the RealSense examples, you can control it via CMake with the BUILD_EXAMPLES variable, as seen the Build Configuration documentation. This only builds a small subset of the examples, however. To build the align-advanced examples, you also need to set BUILD_GRAPHICAL_EXAMPLES:
cd ~/librealsense
mkdir build; cd build
cmake -DBUILD_EXAMPLES=true -DBUILD_GRAPHICAL_EXAMPLES=true ..
make