static void myRotateUpDown( ON_Viewport& viewport, double angle )
{
// rotates camera around the screen x axis
ON_3dVector camX;
ON_3dPoint center;
if ( glb_model )
center = glb_model->m_view.m_target;
else
viewport.GetFrustumCenter( center );
viewport.GetCameraFrame( NULL, camX, NULL, NULL );
myRotateView( viewport, camX, center, angle );
}
static void myRotateView( ON_Viewport& viewport,
const ON_3dVector& axis,
const ON_3dPoint& center,
double angle )
{
ON_Xform rot;
ON_3dPoint camLoc;
ON_3dVector camY, camZ;
rot.Rotation( angle, axis, center );
if ( !viewport.GetCameraFrame( camLoc, NULL, camY, camZ ) )
return;
camLoc = rot*camLoc;
camY = rot*camY;
camZ = -(rot*camZ);
viewport.SetCameraLocation( camLoc );
viewport.SetCameraDirection( camZ );
viewport.SetCameraUp( camY );
ON_GL( viewport ); // update model view
}