Android OpenGL：如何绕世界轴旋转？

Question

I have a touchRotationMatrix that I do the following:

Matrix.setIdentityM(identity, 0);
Matrix.rotateM(identity, 0, x, 0,1,0);
Matrix.multiplyMV(v, 0, identity, 0, v, 0)
Matrix.rotateM(identity, 0, y, 1,0,0);
Matrix.rotateM(identity, 0, y, v[0],v[1],v[2]);     
Matrix.multiplyMM(touchRotationMatrix, 0, identity, 0, touchRotationMatrix, 0);

X and Y are the normalized rotation deltas.

This is applied to my model matrix like so:

Matrix.multiplyMM(mModelMatrix, 0, mModelMatrix, 0,touchRotationMatrix,0);

The problem here is that any rotation that I do is on its own axes.

Let me illustrate why I don't want this:

If I rotate from left to right, it's like turning your head which is good. If I rotate up first, then rotate from left to right, I end up looking at the floor or the ceiling. This makes sense because it is rotating on its axes.

My question is, how do I make it that the x rotation isn't happening on its own axes?

I hope I am clear, any guidance or help would be very much appreciated! Thanks!

PS I'm not an expert in OpenGL nor in LinearAlgebra.

Answer 1

Not so clear but either

Matrix.setRotateM(identity, 0, y, 1,0,0);
Matrix.multiplyMM(touchRotationMatrix, 0, identity, 0, touchRotationMatrix, 0);
Matrix.rotateM(touchRotationMatrix, 0, x, 0,1,0);

or

Matrix.setRotateM(identity, 0, x, 0,1,0);
Matrix.multiplyMM(touchRotationMatrix, 0, identity, 0, touchRotationMatrix, 0);
Matrix.rotateM(touchRotationMatrix, 0, y, 1,0,0);

might work as you expect.