Touch point on the near plane

Question

I have a matrix created with either orthoM or frustumM GL function, where the near plane is logically the surface of the tablet. I would like to translate touch locations to their location on the near plane (that is, from device coordinates to the world coordinates).

I assume this is a common enough activity so I'm wondering if a standard API function exists (or simple sequence) which can provide me with this data?

Answer 1

Take a look at: gluUnPoroject

From the documentation:

Map window coordinates to object coordinates. gluUnProject maps the specified window coordinates into object coordinates using model, proj, and view. The result is stored in obj.