How to use CMake to construct an OpenSceneGraph project?

3
votes

I have just downloaded the OpenSceneGraph source, unzip it into "~/OpenSceneGraph-3.0.1" directory and use CMake to create an out-of-source eclipse make project in "~/OpenSceneGraph-3.0.1-build-eclipse-cdt" directory. When I execute "make" in "~/OpenSceneGraph-3.0.1-build-eclipse-cdt" directory, OpenSceneGraph builds successfully. I have not run "sudo make install" as I do not want to install OpenSceneGraph tightly into my Ubuntu system.

Now I want to use CMake to create a project using the compiled OpenSceneGraph libraries. I use the following codes in CMakeLists.txt :

CMAKE_MINIMUM_REQUIRED(VERSION 2.6)
PROJECT( test_proj )
FIND_PACKAGE(OpenSceneGraph)
ADD_EXECUTABLE(test test.cpp )
INCLUDE_DIRECTORIES(${OPENSCENEGRAPH_INCLUDE_DIRS})
TARGET_LINK_LIBRARIES(test ${OPENSCENEGRAPH_LIBRARIES} )

But it seems that OpenSceneGraph could not be found by CMake.

Does anyone know how CMake could find the compiled OpenSceneGraph libraries in the "~/OpenSceneGraph-3.0.1-build-eclipse-cdt" directory and use it to create projects as if I have tightly installed OpenSceneGraph using "sudo make install". Thanks for any suggestion.

1
cmakeopenscenegraph
What changes did you make to make it work? – Hugues Fontenelle

1 Answers

5
votes

You don't need to install OpenSceneGraph system-wide. Just choose a CMAKE_INSTALL_PREFIX that suits you (eg. ~/osg).

Using the install command makes sure that everything is correctly in place (i.e. in the correct directory structure) for FindOpenSceneGraph.cmake (the script CMake invokes when you call FIND_PACKAGE( OpenSceneGraph ) ) to find it.

Then, you should point any of OSG_DIR, OSGDIR, or OSG_ROOT as environment variable and point it to your install location, so CMake knows where to look for it.

Edit: @Hugues: I'll try to make it a bit clearer:

Setup up OpenSceneGraph:

  1. Get OSG source.
  2. When running CMake for it, choose a CMAKE_INSTALL_PREFIX that suits you, eg. ~/osg if you don't want a system-wide installation in (default) /usr/local. Do it either by stating -DCMAKE_INSTALL_PREFIX=/home/hugues/osg on the command-line or by setting it using a gui tool like ccmake or cmake-gui.
  3. Run make install to build and install OSG.
  4. Set the environment variable OSG_DIR to whatever you pointed CMAKE_INSTALL_PREFIX. (export OSG_DIR=<whereever_you_installed_osg>)

Setup your project:

  1. In your CMakeLists.txt, use FIND_PACKAGE( OpenSceneGraph ) (add desired optional arguments as desired).
  2. Use the resulting variables (like ${OpenSceneGraph_LIBRARIES} in the appropriate places in your cmake file.
  3. Run CMake for your project.