I want to rotate my “camera” around a point of interest. Currently the camera only rotates around the origin.
The standard way:
translate(-P)
rotate
translate(P)
Unfortunately, this doesn’t work. My application uses a translation vector (QVector3D) as well as a quaternion (QQuaternion) to save translation and rotation of the camera.
Currently, it is done like this, which always rotates around the origin:
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(translation.x(),translation.y(), translation.z());
multMatrix(accumulatedQuaternionRotation);
where mulMatrix uses the Quaternion to build a 4x4 matrix which is passed to glMultMatrixf();
Using something like this:
glTranslatef(-translation.x(),-translation.y(), -translation.z());
multMatrix(accumulatedQuaternionRotation);
glTranslatef(translation.x(),translation.y(), translation.z());
results in very weird controls which I’m unable to describe further. In my application translation.z() means: move the camera forward. Changing x() and y() issues a pan like operation.
Help is greatly appreciated.