Mixed order of elements in matrix

When initializing a matrix with all elements, the order of these elements corresponds to row-wise iteration, whereas actual indexing of the matrix elements is done column-wise. That is confusing, and may easily cause errors.

Example code:

var matrix1 = new THREE.Matrix4(0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15);
for (var i = 0; i < matrix1.elements.length; i++) {
  console.log("matrix1[" + i + "] = " + matrix1.elements[i]);
}

Example output:

matrix1[0] = 0
matrix1[1] = 4
matrix1[2] = 8
matrix1[3] = 12
matrix1[4] = 1
matrix1[5] = 5
matrix1[6] = 9
matrix1[7] = 13
matrix1[8] = 2
matrix1[9] = 6
matrix1[10] = 10
matrix1[11] = 14
matrix1[12] = 3
matrix1[13] = 7
matrix1[14] = 11
matrix1[15] = 15 

[WestLangley]

I would leave it the way it is, personally. The API is human-readable.

shadowMatrix.set( 0.5, 0.0, 0.0, 0.5,
                  0.0, 0.5, 0.0, 0.5,
                  0.0, 0.0, 0.5, 0.5,
                  0.0, 0.0, 0.0, 1.0 );

[gero3]

That’s historically grown.

In r1 the math library was row major completely but the graphics renderer was column major which meant we had to transpose the matrices every frame.

In r49 the math library got update to make use of Float32Array and column major to have no problems with the graphics renderer. To make sure the transition would be easy we kept every methods arguments the same because a lot of code was already working with it and not a lot of code needed to know the elements exact value.