Middle drag + Left drag

[asl97]

Implement #2963.
A follow up on #6416.

The middle click is pretty simple, the left click, Honestly, I just throw in some code and got it to work base on the idea in #2963.

Dragging to non empty slot isn't support since it's much more complex, probably out of scope of this pr.

READ: left click drag is mostly just a Proof of Concept, is still mostly a Work in Process and probably Horribly Implemented.

Here is a break down of what I did for the left click

• keep a list of the ItemSpec since the left click was press down
• create an action list and update it every time a new ItemSpec get added
• run all the action in the list when the left click was let go off.
• action list is generated and ran on letting go off the left click as needed

The left click drag display update is only local (afaik).
Only after the left click is let go off then it sends the list of item move action.

There are a number of problem with the left click still, such as

(TODO):

• The click not being detected properly sometimes.
• The first slot where you start the click drag is wonky
• After a while, the inventory is reset to before dragging until the button is let go off.
  (0.14 in video, seem like some kind of lag detection thingy which happen when the server didn't respond to the changes)
  Middle drag + Left drag #6544 (comment)
• Figure out why m_selected_item is gone when the left click is let go off, it causes segmentation fault when the starting drag slot isn't the same as the slot the item came from.
  seem to be due to BLACK MAGIC cause by verifySelectedItem, the source of calling is still unknown.
  • Possible fix: create our own copy of m_selected_item just for left drag
    • Figure out blank image when dragging when using the copy
• Remove all the debugging actionstream
• right click select half (or other method), drag preview has missing unselected amount in the source slot
• leftover preview is wrong when there more slot is selected than item.

Old video: https://www.youtube.com/watch?v=15lDdFRYdkI

[asl97]

Fixed the client revert by adding an inhibiting variable check.

[asl97]

It should be done, Just need a lot of testing as well as commit squashing.

[asl97]

Removed unnecessary whitespace changes, re-added accidentally removed stuff, rebased and squashed into the three main commit.

[asl97]

Just when I thought I am close to done, there are more edge cases in the preview/prediction.

[basicer]

clang gives this warning for me, which seems like a reasonable point.

src/guiFormSpecMenu.cpp:3805:37: warning: comparison of unsigned expression >= 0 is always true [-Wtautological-compare]
                                                        if (m_selected_amount - each >= 0){
                                                            ~~~~~~~~~~~~~~~~~~~~~~~~ ^  ~

[asl97]

@basicer The line number doesn't seem to match, is your copy outdated?
It should be safe to remove though, since it was a left over from when I just add 'slot to drag to' into the list without any condition.

---

I changed the TODO list from strikethough to a task list, there are two more known problem which need to be fix before merging.

One of them is simple, the other gonna need some time.

[paramat]

Middle mouse button needs to be rebindable to a key first, as some 'mouse equivalent devices' have no middle button and poor workarounds for middle-click.

[Fixer-007]

Why not merge this PR and theeen work on rebindable mouse keys? :) So it wont be held hostage for next 1000 years.

[paramat]

@asl97

I changed the TODO list from strikethough to a task list, there are two more known problem which need to be fix before merging.
One of them is simple, the other gonna need some time.

All boxes are ticked, to be clear is this ready now?

[asl97]

It was but stuff happen, something about a refactor and now it's probably broken.

Honestly, this whole PR was mostly just me reacting to you closing #2963 (comment) with "Quite complex", "Old issue and no support, low priority" and not to mention, a ":-1:".

It's a feature that would improve the user experience of the crafting system.
Minetest crafting was (and probably still is) annoying with all the clicking required to place item in their slots.
As such, rejection base on those kind of reason just didn't sit well with me, and thus a PoC click drag was born.

I am gonna just close this since I don't really intent to work on it anymore, mostly because I don't really follow minetest development since... well, long ago.

Feel free to take over or reimplement it.

[paramat]

I've removed my -1 from the issue, i don't disapprove anymore, that was a mistake.
The issue was closed only because there was no core dev support for 2+ years, if there is core dev support the issue will be reopened.
I didn't close it due to my own opinion or disapproval, it takes more than 1 disapproval to close an issue or PR.
I hope this will get some core dev attention other than mine.