M3G is an object-oriented interface consists of 30 classes that can be used to draw complex animated three-dimensional scenes, it provides two ways for developers to draw 3D graphics: immediate mode and retained mode.
In immediate mode, graphics commands are issued directly into the graphics pipeline and the rendering engine executes them immediately. When using this method, the developer must write code that specifically tells the rendering engine what to draw for each animation frame. A camera, and set of lights are also associated with the scene, but is not necessarily part of it. In immediate mode it is possible to display single objects, as well as entire scenes (or worlds, with a camera, lights, and background as parts of the scene).
Retained mode always uses a scene graph that links all geometric objects in the 3D world in a tree structure, and also specifies the camera, lights, and background. Higher-level information about each object—such as its geometric structure, position, and appearance—is retained from frame to frame. In retained mode, data are not serialized by Java's own serialization mechanism. They are optimized by the M3G serialization mechanism, which produces and loads data streams conforming to the .m3gfile format specification for 3D model data, including animation data format. This allows developers to create content on desktop computers that can be loaded by M3G on mobile devices.[2]
Emulation
After the discontinued development of M3G, the emulation has been achieved by an open source Android application called "JL-Mod" in 2020.[3][4]
Further reading
Pulli, Kari; Aarnio, Tomi; Roimela, Kimmo & Vaarala, Jani (2005). "Designing graphics programming interfaces for mobile devices". IEEE Computer Graphics and Applications. 25 (6). IEEE CG&A 2005: 66–75. doi:10.1109/MCG.2005.129. PMID16315479. S2CID8177273.
Aarnio, Callow, Miettinen and Vaarala: Developing Mobile 3D Applications With OpenGL ES and M3G,[5]SIGGRAPH 2005: Courses
Kari Pulli, Tomi Aarnio, Ville Miettinen, Kimmo Roimela, Jani Vaarala: Mobile 3D Graphics with OpenGL ES and M3G, Morgan Kaufmann, 2007, ISBN0-12-373727-3
Claus Höfele: Mobile 3D Graphics: Learning 3D Graphics with the Java Micro Edition, Thomson Course Technology PTR, 2007, ISBN1-59863-292-2
Carlos Morales, David Nelson: Mobile 3D Game Development: From Start to Market, Charles River Media, 2007, ISBN1-58450-512-5