Flight Simulation Software

7 Image Generation Systems

The whole of physics, that is the whole of philosophy of nature is nothing but geometry.

Réné Descartes

The objective of designing an image generation (IG) system for a flight simulator is challenging. It is to create a visual illusion to convince a pilot that they are actually flying in an aircraft, where the view from the simulator flight deck is identical to the view from an aircraft flight deck.

7.1 IG Pipeline

In many flight simulators, the trend is to purchase a real-time rendering system off the shelf; for example, OpenSceneGraph (http://www.openscenegraph.org) is an open-source graphics toolkit capable of rendering complex scenes in real time. A number of commercial packages are also available including Unity (https://unity.com), which provides a comprehensive library to integrate user software, and UnReal (https://www.unrealengine.com). In addition, simulation games including X-Plane and Microsoft Flight Simulator include a renderer which can be accessed independently. The alternative, of developing a renderer from scratch, although feasible, is generally impractical as the requirements of a real-time renderer for 3D graphics (Akenine-Moller et al., 2008) are particularly demanding:

• Rendering a detailed scene at least 50 times per second.
• Transforming millions of 3D textured triangles to 2D triangles per frame.
• Acquiring the position and orientation of the pilot eye-point from the simulator.
• Loading visual databases of various formats. ...