I have a circular shape object, which I want to rotate like a fan along it's own axis.

I can change the rotation in any direction i.e. dx, dy, dz using my transformation matrix.

The following it's the code:

 Matrix4f matrix = new Matrix4f();
 Matrix4f.translate(translation, matrix, matrix);
 Matrix4f.rotate((float) Math.toRadians(rx), new Vector3f(1,0,0), matrix, matrix);
 Matrix4f.rotate((float) Math.toRadians(ry), new Vector3f(0,1,0), matrix, matrix);
 Matrix4f.rotate((float) Math.toRadians(rz), new Vector3f(0,0,1), matrix, matrix);
 Matrix4f.scale(new Vector3f(scale,scale,scale), matrix, matrix);

My vertex code:

 vec4 worldPosition = transformationMatrix * vec4(position,1.0);
 vec4 positionRelativeToCam = viewMatrix*worldPosition;
 gl_Position = projectionMatrix *positionRelativeToCam;

Main Game Loop:


But, it's not rotating along it's own axis. What am I missing here? I want something like this. Please Help

Like This

  • $\begingroup$ What is it doing instead? Is it rotating along a different axis? $\endgroup$ – Julien Guertault Oct 2 '16 at 11:35
  • $\begingroup$ I wanted to read your question but that animated gif is too distracting. $\endgroup$ – 3Dave Oct 5 '16 at 23:07

Instead of "stacking" or overwriting these transformations on one matrix You may try doing that using matrix multiplication:

Matrix4f translate = translate(translation,  new Matrix4F() /*identity*/);
Matrix4f rotateX = rotate((float) Math.toRadians(rx), new Vector3f(1,0,0), new Matrix4F());
Matrix4f scale = scale(new Vector3f(scale,scale,scale), new Matrix4F());

Matrix4f transformation = translate*rotateX*scale;
| improve this answer | |
  • $\begingroup$ Do you know if this solves the problem? $\endgroup$ – trichoplax Oct 3 '16 at 7:17
  • $\begingroup$ I believe the problem was not rotating along its own axis so doing it this way should solve it. Maybe there are other solutions $\endgroup$ – narthex Oct 3 '16 at 15:06

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