GLKMatrix4 type defines a
4x4 floating-point matrix as well as many mathematical operations commonly used to manipulate matrices. 3D graphics programming uses matrices extensively as a convenient way to represent a graphical transformation between different coordinate systems. These transformations include translation, scaling, rotation and projection; through matrix multiplication, multiple transformations can be concatenated into a single transformation matrix.
The functions that manipulate
GLKMatrix4 structures treat the inputs as immutable, instead returning a new matrix that represent the results of the operation.