Again, hi all.

So, apparently I skipped a few years of math from highschool about vectors and angles grin here we go again...

To describe the problem better, I want to 'drag' a point of the sphere surface, thats under my mouse pointer, to a new location on the sphere surface. I'm either close, but visibly inaccurate or completely off...

I'm tracing two rays from mouse pos to a sphere (gizmo) and I get the two points coordinates relative to the model origin with:
Code:
vec_set( m3dStartPos , vector( mouse_pos.x , mouse_pos.y , 1 ) );
vec_set( m3dEndPos , vector( mouse_pos.x , mouse_pos.y , 1000 ) );
vec_for_screen( m3dStartPos , camera );
vec_for_screen( m3dEndPos , camera );
you = puppet;
result = c_trace( m3dStartPos , m3dEndPos , IGNORE_YOU | USE_POLYGON );
if( result > 0 ) {
	// Get local point position (relative to my sphere)
	vec_diff( oldContactPos , hit.x , my.x );
}

wait(1);

vec_set( m3dStartPos , vector( mouse_pos.x , mouse_pos.y , 1 ) );
vec_set( m3dEndPos , vector( mouse_pos.x , mouse_pos.y , 1000 ) );
vec_for_screen( m3dStartPos , camera );
vec_for_screen( m3dEndPos , camera );
you = puppet;
result = c_trace( m3dStartPos , m3dEndPos , IGNORE_YOU | USE_POLYGON );
if( result > 0 ) {
	// Get local point position (relative to my sphere)
	vec_diff( contactPos , hit.x , my.x );
}

"My" is the sphere.

And I'm trying to rotate my gizmo so that oldContactPos will move to the new contactPos location.
All attempts failed, here's the last two:
Code:
if( vec_dist( oldContactPos , contactPos ) > 0 ) {
	VECTOR dir1 , dir2 , axis1 ;
	ANGLE oldAng , newAng , diffAng ;

//
// Using vec_to_angle to orient two angles
// and get the difference needed to rotate the gizmo
/*	vec_set( dir1 , contactPos );
	vec_set( dir2 , oldContactPos );
	vec_to_angle( oldAng , oldContactPos );
// Here roll becomes 2xxx, so I reset it to 0
// But I think I need roll too, to be a realistic rot.?
	oldAng.roll = 0;
	vec_to_angle( newAng , contactPos );
	newAng.roll = 0;
	ang_diff( diffAng , newAng , oldAng );

	ang_add( my.pan , diffAng );
	ang_add( my.local_pan , diffAng );
*/

//
// Using ang_for_axis to rotate the objects angles
// by the angle difference of the two points
// around axis - cross product of the two points
// (relative to local object space)
	vec_set( dir1 , oldContactPos );
	vec_set( dir2 , contactPos );
	vec_cross( axis1 , dir1 , dir2 );
	vec_set( newAng , my.pan );
	vec_normalize( dir1 , 1 );
	vec_normalize( dir2 , 1 );
	ang_for_axis( newAng , axis1 , acosv( vec_dot( dir1 , dir2 ) ) );

	ang_add( my.pan , newAng );
	ang_add( my.local_pan , newAng );
}


Anyone know why both methods fail? I have no idea what I'm doing wrong, but this must be my 20-th attempt doing the same stuff and always wrong...

Thanks in advance.

Extensive Multiplayer tutorial:
http://mesetts.com/index.php?page=201