Setting up an OGRE project

Note

see BuildingOgre.md for instructions how to build OGRE itself

CMake Configuration

Ogre uses CMake as its build system. It is recommended that you use it in your project as well. Then all you need is to add the following three lines to your project

# specify which version you need
find_package(OGRE 1.10 REQUIRED)

# the search paths
include_directories(${OGRE_INCLUDE_DIRS})
link_directories(${OGRE_LIBRARY_DIRS})

# copy essential config files next to our binary where OGRE autodiscovers them
file(COPY ${OGRE_CONFIG_DIR}/plugins.cfg ${OGRE_CONFIG_DIR}/resources.cfg
     DESTINATION ${CMAKE_BINARY_DIR})

These settings include all available components and third party libraries OGRE depends on (e.g. boost) - nothing more to do.

If you installed OGRE in a non-standard path, you will have to set OGRE_DIR to the location of OGREConfig.cmake so find_package can figure out the rest.

For inspecting the detected OGRE installation, the following CMake variables are available

• OGRE_STATIC - whether ogre was build as static lib
• OGRE_${COMPONENT}_FOUND - ${COMPONENT} is available
• OGRE_PLUGIN_DIR - The directory where the OGRE plugins are located
• OGRE_MEDIA_DIR - The directory where the OGRE sample media is located
• OGRE_CONFIG_DIR - The directory where the OGRE config files are located

Application skeleton

The easiest way to get started is the OgreBites Component. It handles Ogre startup/ tear down (including Ogre::Overlay, RTSS), input using SDL2 and even includes a Simple GUI System.

This is useful if all you want is to get a Scene with a FPS counter up and running (rapid prototyping). If available it also uses SDL2 for input - you now just have to implement the callbacks.

To use it, simply derive from OgreBites::ApplicationContext and if you want to get input events from OgreBites::InputListener

class MyTestApp : public OgreBites::ApplicationContext, public OgreBites::InputListener
{
    ...
}

in the constructor we set our application name. The ogre configuration files will be stored in a system dependant location specific to our app.

MyTestApp::MyTestApp() : OgreBites::ApplicationContext("OgreTutorialApp")
{
}

to handle input events, we then override the according method

bool MyTestApp::keyPressed(const OgreBites::KeyboardEvent& evt)
{
    if (evt.keysym.sym == SDLK_ESCAPE)
    {
        getRoot()->queueEndRendering();
    }
    return true;
}

the interesting part however is the setup method

void MyTestApp::setup(void)
{
    // do not forget to call the base first
    OgreBites::ApplicationContext::setup();
    
    // register for input events
    addInputListener(this);

    // get a pointer to the already created root
    Ogre::Root* root = getRoot();
    Ogre::SceneManager* scnMgr = root->createSceneManager();

    // register our scene with the RTSS
    Ogre::RTShader::ShaderGenerator* shadergen = Ogre::RTShader::ShaderGenerator::getSingletonPtr();
    shadergen->addSceneManager(scnMgr);

    // without light we would just get a black screen    
    Ogre::Light* light = scnMgr->createLight("MainLight");
    Ogre::SceneNode* lightNode = scnMgr->getRootSceneNode()->createChildSceneNode();
    lightNode->setPosition(0, 10, 15);
    lightNode->attachObject(light);

    // also need to tell where we are
    Ogre::SceneNode* camNode = scnMgr->getRootSceneNode()->createChildSceneNode();
    camNode->setPosition(0, 0, 15);
    camNode->lookAt(Ogre::Vector3(0, 0, -1), Ogre::Node::TS_PARENT);

    // create the camera
    Ogre::Camera* cam = scnMgr->createCamera("myCam");
    cam->setNearClipDistance(5); // specific to this sample
    cam->setAutoAspectRatio(true);
    camNode->attachObject(cam);

    // and tell it to render into the main window
    getRenderWindow()->addViewport(cam);

    // finally something to render
    Ogre::Entity* ent = scnMgr->createEntity("Sinbad.mesh");
    Ogre::SceneNode* node = scnMgr->getRootSceneNode()->createChildSceneNode();
    node->attachObject(ent);
}

Note

The above code is explained in detail in Your First Scene.

finally we start everything as

int main(int argc, char *argv[])
{
    MyTestApp app;
    app.initApp();
    app.getRoot()->startRendering();
    app.closeApp();
    return 0;
}

Note

You can find the full code of the above example at

• Samples/Tutorials/Bootstrap.cpp for C++
• Samples/Python/bites_sample.py for Python
• Samples/AndroidJNI/MainActivity.java for Java (Android)

OgreBites itself is also a good starting point if you need more control over the Camera or the Window creation. For instance to render into an existing Qt Window.

See also

Ogre::Root::renderOneFrame

Ogre::RenderSystem::_createRenderWindow

Ogre::RenderSystem::preExtraThreadsStarted