Row/Column major matrices

That's a row-major matrix. All arrays are 'row-major' in a sense since increasing index values would take you horizontally across a row. When you pass an array to an OpenGL matrix-related function, it'll interpret the array in a column-major fashion as such:

float mat[9];

mat[0] = 1;
mat[1] = 4;
mat[2] = 9;
mat[3] = 5;
mat[4] = 6;
mat[5] = 7;
mat[6] = 4;
mat[7] = 2;
mat[8] = 1;

would produce a matrix interpreted as

1 5 4
4 6 2
9 7 1

Don't think of a row-major and column-major matrix as being stored differently in memory, they're not, it's just simply how they're interpreted. We're used to reading from index 0 to n-1, say, and defining that as row 0. OpenGL reads index 0 to n-1 and defines that as column 0.

edit: spelling

[edited by - chawk on December 30, 2003 1:46:48 PM]