HPL Engine

HPL Engine

Opening a chest using the physics code in Penumbra: Overture
Developer(s)	Frictional Games
Written in	C++
Platform	Windows, Mac OS X, Linux, PS4
Type	Game engine
License	Proprietary (HPL2-3) / GNU General Public License (HPL1)
Website

The HPL Engine is a 3D game engine created by Frictional Games. The engine, named after the initials of horror author H. P. Lovecraft, was started in December 2004, as a thesis job for a 2D platform game Energetic, released in 2005. The functionality for 3D games was added later, which culminated in Penumbra Tech Demo in 2006. In 2010, the first version of the engine (HPL1) together with Penumbra: Overture was released as open source under the GPL license, after the Humble Indie Bundle promotion finished.

HPL is a cross-platform game engine which is compatible with the OpenGL, OpenAL, and Newton Game Dynamics libraries. One of the engine's defining features is its ability for advanced object interaction through the use of Newton's physics code.

The first incarnation of HPL was demonstrated by the original Penumbra Tech Demo. The developers admitted to making significant modifications of the original engine to accommodate the 3D graphics in this game, "The engine is built from an engine created when making a thesis job which resulted in the platform game Energetic. Before moving into the 3rd dimension I made some cleanup of the engine (which was quite rushed in some places) and started to add a base for 3D rendering. I would not say that the original 2D engine was modified to add 3D, but rather a 3D layer was added so all of the 2D stuff is still there. It is still possible to make a 2D tile game using our engine." Another innovative feature of the engine was its ability to have static as well as dynamic shadows, allowing people with less powerful video cards to still experience some shadowing effects without the need of having to dynamically render them.

Penumbra: Overture was released as part of the Humble Indie Bundle, and when the Bundle made more than $1 million, Overture was released under the GNU General Public License. This release included the game engine and development tools.