I am writing a rather simple android game and I am implementing Open GL to draw a 3D cube that spins upon the X, Y and Z axis and I need to know where the user has clicked on the texture of the cube.

The texture is a simple square bitmap (100x100) that has a smaller square in the center. I need to know if the user touches the inner square. As well was tell which face of the cube the user touches. Does anyone know how this can be accomplished if not can anyone give some pseudo code on how to tell where the ray correlates to the texture? Or at least point me in the right direction.

The textures of each face are like this:

The code I am using is from: http://www3.ntu.edu.sg/home/ehchua/programming/android/Android_3D.html2.9 It is a port to android from Lesson 6 NeHe. Example 6a: Photo-Cube