Ok guys, actually I am stuck on my program since 2 days and I dont know what to do…

Right now, I am rendering a cylinder, I can pan and zoom using this:

```
display() {
...
glu.gluLookAt(translationX/gLAutoDrawable.getWidth()*scale*2,
-translationY/gLAutoDrawable.getHeight()*scale*2, 2,
translationX/gLAutoDrawable.getWidth()*scale*2,
-translationY/gLAutoDrawable.getHeight()*scale*2, 0,
...
}
```

I can also rotate using some custom functions:

```
display() {
...
glu.gluLookAt
...
gl.glMultMatrixf(currentRotation, 0);
...
}
mouseDragged() {
...
if(rotationMode) {
float newRotation[] = multiply(rotationX(-dy), rotationY(-dx));
currentRotation = multiply(currentRotation, newRotation);
rotationX +=dx;
rotationY +=dy;
}
...
}
private static float[] rotationX(float angleDeg) {
float m[] = identity();
float angleRad = (float)Math.toRadians(angleDeg);
float ca = (float)Math.cos(angleRad);
float sa = (float)Math.sin(angleRad);
m[ 5] = ca;
m[ 6] = sa;
m[ 9] = -sa;
m[10] = ca;
return m;
}
private static float[] rotationY(float angleDeg) {
float m[] = identity();
float angleRad = (float)Math.toRadians(angleDeg);
float ca = (float)Math.cos(angleRad);
float sa = (float)Math.sin(angleRad);
m[ 0] = ca;
m[ 2] = -sa;
m[ 8] = sa;
m[10] = ca;
return m;
}
private static float[] multiply(float m0[], float m1[]) {
float m[] = new float[16];
for (int x=0; x < 4; x++) {
for(int y=0; y < 4; y++) {
m[x*4 + y] = m0[x*4+0] * m1[y+ 0] +
m0[x*4+1] * m1[y+ 4] +
m0[x*4+2] * m1[y+ 8] +
m0[x*4+3] * m1[y+12];
}
}
return m;
}
```

This special rotation was mandatory because if I use glRotate to rotate my cylinder a first time over the horizontal plane, lets say, then my modelview coordinates rotates as well, and I dont want to have this, since I still need to rotate over the vertical axes

Now, the problem is that the rotation is performed taking the modelview origin as the rotation point…

This means that if I pan (aka move the camera) I would like to see a rotation over the center of my screen, and not the center of the modelview (that has been panned)

I hope it’s clear, otherwise I can post something else to illustrate it better…