transform_mesh_to_line.gd

func calc_final_transform(_mag_vector,_offset,_width):
    """
    

    this calculates a final transform to rotate a cylinder
    
    this cylinder goes from (0,0,0) to (1,0,0)
    
    so it is basicly 1 unit long along the x axis
    
    WARNING:
        the maths in this simple project took a while to figure out and had many changes
        unfortunatly so some of the logic of the acos
        
        some of the corrections avoids entering 0 into a divion or atan
        
        basicly created with some trial and error so the notes are incomplete


    to use this as a to and from:
    
    _mag_vector = to - from
    _offset = from


    """

    var mag_vector_copy = _mag_vector # correcting backwards bug (UNSURE STILL
    mag_vector_copy.x = -mag_vector_copy.x
    mag_vector_copy.z = -mag_vector_copy.z

    var trans = Transform() # our transform matrix
    
    # stretch to the right length
    trans = trans.scaled(Vector3(mag_vector_copy.length(),_width,_width))
    
    var A = sqrt(pow(mag_vector_copy.x, 2.0) + pow(mag_vector_copy.z,2.0))
    #only rotate 2nd time if y is not 0, this elimnates a scene destroying bug!
    
    # rotate the on the z axis as the pitch
    if mag_vector_copy.y != 0.0: # avoids a bug? (no pitch required if no y on mag_vector)
        var H = mag_vector_copy.length()
        var theta = acos(A/H)
        if mag_vector_copy.y < 0.0: # WEIRD CORRECTION!!
            theta = -theta
    
        trans = trans.rotated(Vector3(0.0,0.0,1.0), theta)
        
    # rotate around the horizon as the direction (needs to be second rotation)
    trans = trans.rotated(Vector3.UP,atan2(mag_vector_copy.z,-mag_vector_copy.x))
    
    # this moves the offset (ignoring the scale and rotation), done last
    trans.origin += _offset 

    return trans