What is a matrix?
A matrix is a two-dimensional array of numbers. A square matrix is one whose width and height are the same. In this chapter, you will implement a 4 x 4 matrix; that is, a matrix with four rows and four columns. The elements of this matrix will be stored as a linear array.
A 4 x 4 matrix can be thought of as four vectors that have four components each, or an array of
vec4s. If the vectors represent the columns of the matrix, the matrix is column-major. If the vectors represent the rows of the matrix, it is row-major.
Assuming a 4 x 4 matrix contains the letters A, B, C, D … P of the alphabet, it can be constructed as either a row- or column-major matrix. This is demonstrated in the following Figure 3.1:
Most math books and OpenGL use column-major matrices. In this chapter, you will be implementing column-major matrices as well. Understanding what is in a matrix is important....