Lightsmark is a cross-platform benchmark and demonstration software that allows real-time global illumination and penumbra shadows to be visualized. Its main feature is the ability to simulate real-time global illumination, which is especially important for making artificial graphics look more realistic. Before Lightsmark, real-time global illumination was limited to small scenes, low resolutions, and slow speeds and required specially designed scenes with manual optimizations. Lightsmark breaks these limits by running on a reasonably sized scene (220000 triangles) in high resolution (1920x1200) at excellent speed (over 300 fps). Lighting is automatically calculated on an original unmodified scene from the 2007 World of Padman game.

The last version of Lightsmark was released in August 2008 and has since been discontinued. Although it is very specialized software, it includes support for Linux and is compatible with 32-bit and 64-bit systems.

The latest version includes improvements such as a faster engine (up to 3x faster fps, so the results are different), increased realism (indirect shadows and per-pixel color bleeding), Linux support (it was only available for Windows), and native 64-bit support (it was only available on 32-bit). In addition, all GPUs use the same rendering path (in 2007, they did not work due to a driver bug), and minor rendering fixes have been made (sun shadow, robot back faces). One of the most frequently asked questions about Lightsmark is whether its score depends on CPU performance. The answer is yes, as the CPU solves part of the lighting equation to make it faster. This simulates the optimal usage in a real game. Another common topic of the question is how to change the resolution or run the software windowed in Linux and how to disable music during execution. Both issues can be solved by running "backend ?" and following the instructions provided.

In case you encounter any problems while installing or running Lightsmark, it is recommended to check that you have installed the latest graphics driver available (as of June 2008) and send a detailed report of the problem along with a generated log.txt file to the Lightsmark directory. If installed on Windows Vista, you may need to find the log.txt file in the Lightsmark 2008 directory. If you get an error message that a Microsoft Visual C++ 2008 redistribution package is missing, you need to download and install the appropriate version for your system (x86 for 32-bit or x64 for 64-bit). Another common problem is that the Opera downloader changes the file extension from .msi to .exe, which can be fixed by manually changing the extension back to .msi.