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Open scene graph

Simulation

OpenSceneGraph (OSG) is an open-source 3D graphics toolkit written in C++, built on top of OpenGL. It provides a high-level scene graph abstraction for building, rendering, and managing complex 3D scenes efficiently.

Common use case

Area Description
Simulation & Training Flight simulators, military simulators, driving trainers
Scientific Visualization Displaying large 3D datasets or terrains
Geospatial Systems Used by osgEarth to render real-world maps and terrain
Virtual Reality (VR) Basis for immersive 3D visualization
Game Engines / Tools Lightweight base for building visualization or engine tools

OSG Earth

Install

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git clone https://github.com/openscenegraph/OpenSceneGraph.git
cd OpenSceneGraph
mkdir build
cd build
cmake ..
make
sudo make install
suod ldconfig

Demo

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#include <osgViewer/Viewer>
#include <osg/ShapeDrawable>

int main() {
    osg::ref_ptr<osg::Group> root = new osg::Group();
    root->addChild(new osg::ShapeDrawable(new osg::Sphere(osg::Vec3(0,0,0), 1.0)));

    osgViewer::Viewer viewer;
    viewer.setSceneData(root);
    return viewer.run();
}

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cmake_minimum_required(VERSION 3.10)
project(SimpleOSGApp)

set(CMAKE_CXX_STANDARD 17)

find_package(OpenSceneGraph REQUIRED COMPONENTS osg osgDB osgUtil osgViewer)

# Create executable
add_executable(osg_example hello.cpp)

# Link OSG libraries
target_link_libraries(osg_example
    PRIVATE
        osg
        osgDB
        osgUtil
        osgViewer
)

Learn path create by chatGPT

Each week builds on the previous one. For each topic, I’ve included:

  • 🎓 Concepts — what you’ll learn
  • 💻 Practice Goals — what you’ll implement
  • 📚 Resources — where to learn more

🗓️ Week 1 – Setup & Core Concepts

Goal: Understand what OSG is, how it organizes scenes, and render your first object.

🎓 Concepts - Scene graph structure (Nodes, Groups, Geodes) - Viewer and event loop (osgViewer::Viewer) - Geometry, Drawables, and simple shapes - Installing OSG and using CMake with VSCode

💻 Practice

  • ✅ Install OSG (sudo apt install libopenscenegraph-dev)
  • ✅ Build your first program (sphere example)
  • ✅ Add multiple shapes (cube + sphere + cone)
  • ✅ Use osg::Group to attach nodes
  • ✅ Experiment with osgViewer::Viewer::run()

📚 Resources

OSG Wiki – Getting Started

🗓️ Week 2 – Transforms & Cameras

Goal: Learn to position objects and control the camera.

🎓 Concepts

  • Transform nodes (osg::MatrixTransform)
  • Local vs global coordinates
  • Orbit manipulator (osgGA::OrbitManipulator)
  • Camera node (osg::Camera)

💻 Practice

  • ✅ Move an object using MatrixTransform
  • ✅ Animate a rotation using osg::AnimationPathCallback
  • ✅ Add a camera and control with mouse (OrbitManipulator)
  • ✅ Play with setHomeViewpoint() to set default view

📚 Resources

Example: examples/osganimationpath

Camera Manipulators Doc

🗓️ Week 3 – Models, Materials & Lighting

Goal: Load real 3D models and make your scene look realistic.

🎓 Concepts

  • Loading models (osgDB::readNodeFile)
  • Materials, textures, and lights
  • StateSets (managing OpenGL state)
  • Shaders overview

💻 Practice

  • ✅ Load a .obj or .osgb model
  • ✅ Add texture using osg::Texture2D
  • ✅ Add a light source (osg::LightSource)
  • ✅ Adjust materials via osg::Material

📚 Resources

  • Example: examples/osglight
  • Example: examples/osgshadercomp
  • Book: Beginner’s Guide Ch. 4–6

🗓️ Week 4 – Interaction & Events

Goal: Make the scene respond to input.

🎓 Concepts

  • Event handlers (osgGA::GUIEventHandler)
  • Keyboard and mouse input
  • Picking (selecting objects with mouse)
  • Callbacks (update, cull, draw)

💻 Practice

  • ✅ Create a custom event handler for key presses
  • ✅ Implement simple object movement (e.g., arrow keys to move)
  • ✅ Add text overlay using osgText::Text
  • ✅ Implement a basic “object picker”

📚 Resources

🗓️ Week 5 – Performance & Advanced Features

Goal: Understand optimization and advanced scene graph concepts.

🎓 Concepts

  • Level of Detail (osg::LOD)
  • Culling and bounding volumes
  • Paging (loading large datasets dynamically)
  • Multithreaded rendering overview
  • Using shaders (GLSL in OSG)

💻 Practice

  • ✅ Create LOD nodes for distant objects
  • ✅ Visualize bounding boxes (osg::BoundingBox)
  • ✅ Try replacing default shader with custom GLSL
  • ✅ Explore example: osgmultitexture

📚 Resources

  • Example: examples/osglod
  • OSG Rendering Optimization

🗓️ Week 6 – Integration & osgEarth

Goal: Combine what you learned and build a mini-project.

🎓 Concepts

  • osgEarth basics (MapNode, ImageLayer, ElevationLayer)
  • Adding UI (Qt or ImGui optional)
  • Combining 3D models + terrain
  • Exporting and saving scenes

💻 Practice

  • ✅ Install osgEarth (sudo apt install osgEarth)
  • ✅ Load OpenStreetMap base layer
  • ✅ Add a model (e.g., aircraft or robot) at specific lat/lon
  • ✅ Use OrbitManipulator to explore the map
  • ✅ Export scene with osgDB::writeNodeFile()

📚 Resources

  • osgEarth GitHub: https://github.com/gwaldron/osgearth

🧩 Optional Weeks (7+)

  • Week 7 → integrate with Qt GUI (using osgQt::GLWidget)
  • Week 8 → build plugin or viewer utility
  • Week 9 → add VR support (OpenVR / Oculus)
  • Week 10 → integrate with ROS 2 or simulation data (e.g., real sensor visualization)

Reference