2 replies to this topic

[SM ForeveR]

Hi, I am developing on android and I have encountered one problem. In opengl documentation it says, that matrices are in column-major order and translation matrix looks like this:
1 0 0 x
0 1 0 y
0 0 1 z
0 0 0 1
But in my program I use method like this:

public static final float[] translation(float x, float y, float z) {

  // 4x4 translation matrix.

  return new float[] {

	1.0f, 0.0f, 0.0f, 0.0f,

	0.0f, 1.0f, 0.0f, 0.0f,

	0.0f, 0.0f, 1.0f, 0.0f,

	x, y, z, 1.0f,

  };

}

And it works until I try to change x, y, z position to last column.
Does this have to do with the fact that I use 1D array and not 2D? Does each row in this array represents a column when passed to opengl methods?

Thank you,
Martin

[V-man]

yes

[mhagain]

You can use row major in your own code if you want - absolutely nothing to stop you. What's important is that you're consistent (otherwise you'll risk confusing yourself) and that you transpose the matrix to column-major before sending it to OpenGL. Yes, that's a few extra operation, but it's something you should be doing relatively few times per frame, so any performance impact will be down in the noise.