ogre

OGRE, which stands for Object-Oriented Graphics Rendering Engine, is a long-running open-source library for building 3D graphics applications. It acts as a rendering backend: rather than drawing 3D scenes directly using low-level graphics APIs like Vulkan, Direct3D, or OpenGL, developers write code against OGRE's API and it handles the differences between those backends. This makes it easier to build applications that run across different operating systems and hardware configurations without rewriting graphics code for each one.

The library includes a wide range of 3D rendering features: physically based shading for realistic material surfaces, multiple shadow techniques, skeletal character animation, particle systems for effects like fire and smoke, terrain rendering with level-of-detail handling, post-processing effects like bloom and HDR, and volumetric rendering. It also integrates with the Dear ImGui toolkit for building in-app user interfaces and with the Bullet physics library for simulating rigid body dynamics. These are shown in the README with screenshots of each feature.

OGRE is written in C++ but also has Python bindings that let you get a 3D scene running in just a few lines of Python code. The README shows an example that creates a window, loads a 3D model in glTF format, adds a light, and runs a render loop. There is also support for C# and Java. A WebAssembly demo can be run directly in a browser, and a prebuilt Windows SDK is available for trying it without compiling from source.

The library has been in active use since 2001 and appears in robotics simulation tools, the ROS visualization tool rviz, OpenCV's visualization module, and several commercial and open-source games including Torchlight II. It is licensed under the MIT license and accepts community contributions.