PTK is a 2D rendering engine and SDK developed by Phelios, Inc., that allows computer programmers create downloadable games in C++ that are portable to Microsoft Windows and Mac OS X. It is currently used by about 60 downloadable games ^[1] It is mainly known for powering breakaway casual hits from funpause and Big Fish Games, such as Azada, Atlantis, Atlantis Sky Patrol, Mystic Inn and Fairies.

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PTK was designed for programmers to enjoy basic-like ease of programming using the C++. It abstracts rendering, input and I/O and removes the need for directly setting up complex renderers such as DirectX or OpenGL.^[jargon]

PTK uses a "2D in 3D" paradigm. While it is a 2D engine, it uses 3D acceleration for rendering, enabling very good, bicubic filtered rendering of scaled, rotated sprites and per-pixel alpha blending at no expense of computing time. A game such as Mystic Inn make extensive use of PTK's rendering capabilities.^[jargon]