add drag and drop for rails in editor :)

[DasCapschen]

Fixed #151 😄

don't merge just yet, there might be some bugs.
we might want to add a minimum radius.

[HaSa1002]

Cursor is offset.
Repro:

1. Create Rail with curvature
2. Add new rail using "after rail"
3. Drag the endpoint of the second rail

[HaSa1002]

if you drag the endpoint onto the movement gizmo, you trigger the movement

[HaSa1002]

Issue is not related to PR
power line is not updated correctly

[HaSa1002]

I would favor if you could change the addition behaviour to (but not a blocker and can be made in a follow-up PR):

1. Tell game, you want to add a rail
2. Move your mouse to start position
3. Press LMB and hold
   1. If near other rail, snap to that rail and get curvature and radius from that rails
   2. Else set Rotation to 0
4. Drag rail
5. Release LMB to end action

[DasCapschen]

ty for review

• style changes applied
• cursor offset fixed
• ui updates while dragging
• gizmo hidden while dragging (gizmo itself still broken)
• powerline is a Rail.gd issue
• gonna code snapping now :)

[HaSa1002]

I doesn't do anything after I press OK and instead get that error:

ERROR: Signal 'confirmed' is already connected to given method '_snap_complex_connector' in that object.
   At: core/object.cpp:1512

[HaSa1002]

and when it starts to show the text box, it says:

ERROR: Signal 'confirmed' is already connected to given method '_snap_complex_connector' in that object.
   At: core/object.cpp:1512
[]
ERROR: Signal 'confirmed' is already connected to given method '_snap_complex_connector' in that object.
   At: core/object.cpp:1512
[]
ERROR: Signal 'confirmed' is already connected to given method '_snap_complex_connector' in that object.
   At: core/object.cpp:1512
[]
ERROR: Signal 'confirmed' is already connected to given method '_snap_complex_connector' in that object.
   At: core/object.cpp:1512
[]
ERROR: Signal 'confirmed' is already connected to given method '_snap_complex_connector' in that object.
   At: core/object.cpp:1512

[DasCapschen]

Looks like you're triggering the complex connector, for arbitrary connections. That's not implemented yet, I guess I should have disabled the popup for it, but as it stands, this PR is WIP.

Signal errors should be fixed with a simple if check. (though I kinda wish godot just wouldn't throw an error on double connect...)
I have no idea where the [] print comes from...

[HaSa1002]

Yeah I figured the signals will be connected multiple times, because the snapping is in place, but the the popup connection logic is triggered every snapping mouse movement frame.

That is totally fine. I was just super confused, but I found the two working use cases, so no worried there (although the complex one may be used even in the 90° case).

[HaSa1002]

🥳