Support AB / XY Button Swapping / Remap

[dcvz]

This PR primarily adds support for swapped AB & XY buttons (classic on Nintendo consoles)

It also disables SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE for the __SWITCH__ platform but I'm not sure if its ok to add this check when there's no build workflow for it. Though one could likely be added using homebrew development tools. But again that's up for discussion.

[dcvz]

The specific __SWITCH__ check could be replaced with a generic IMGUI_ define

[ocornut]

It also disables SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE for the SWITCH

Please clarify why you need to disable SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE.
Which function is failing or returning an error?
What does SDL_GetCurrentVideoDriver() return on your system?
Can you specify which SDK that is for (official or unofficial one, which one if the later).

This PR primarily adds support for swapped AB & XY buttons (classic on Nintendo consoles)

I think it would be preferable to provide a backend-agnostic and less intrusive alternative, e.g. by iterating g.InputEventsQueue[], and when event->Type == ImGuiInputEventType_Key check for event->Key.Key and swap A/B and X/Y.

[ocornut]

I think it would be preferable to provide a backend-agnostic and less intrusive alternative, e.g. by iterating g.InputEventsQueue[], and when event->Type == ImGuiInputEventType_Key check for event->Key.Key and swap A/B and X/Y.

Here's a function doing that (untested)

#include "imgui_internal.h"

void ImGui_ImplSwitch_SwapABXY(int start_event)
{
    auto& input_queue = ImGui::GetCurrentContext()->InputEventsQueue;

    for (int n = start_event; n < input_queue.Size; n++)
    {
        ImGuiInputEvent& e = input_queue[n];
        if (e.Type == ImGuiInputEventType_Key)
        {
            switch (e.Key.Key)
            {
            case ImGuiKey_GamepadFaceLeft:  e.Key.Key = ImGuiKey_GamepadFaceUp; break;   // X<>Y
            case ImGuiKey_GamepadFaceUp:    e.Key.Key = ImGuiKey_GamepadFaceLeft; break;
            case ImGuiKey_GamepadFaceRight: e.Key.Key = ImGuiKey_GamepadFaceDown; break;   // X<>B
            case ImGuiKey_GamepadFaceDown:  e.Key.Key = ImGuiKey_GamepadFaceRight; break;
            }
        }
    }
}

Usage:

// Start the Dear ImGui frame
const int input_queue_size_before = ImGui::GetCurrentContext()->InputEventsQueue.Size; // record event count before backend submit them
ImGui_ImplDX11_NewFrame();
ImGui_ImplWin32_NewFrame();

// Call between backend and main lib NewFrame():
ImGui_ImplSwitch_SwapABXY(input_queue_size_before);

ImGui::NewFrame();

[ocornut]

As the imgui core code never actually uses ImGuiKey_GamepadFaceXXX input directly but uses those alias with extra semantic:

#define ImGuiKey_NavGamepadActivate     ImGuiKey_GamepadFaceDown
#define ImGuiKey_NavGamepadCancel       ImGuiKey_GamepadFaceRight
#define ImGuiKey_NavGamepadMenu         ImGuiKey_GamepadFaceLeft
#define ImGuiKey_NavGamepadInput        ImGuiKey_GamepadFaceUp

Another and more correct solution would be to allow you to redefine those, then access to e.g. ImGuiKey_GamepadFaceUp are actually correct. In practice, I suspect this is going to be more dangerous as it likely that either core lib or extension or user code would eventually mix things up. I'll advise just swapping as suggested above.

Closing as solved but let me know if you have any more issue.

[dcvz]

I think it would be preferable to provide a backend-agnostic and less intrusive alternative, e.g. by iterating g.InputEventsQueue[], and when event->Type == ImGuiInputEventType_Key check for event->Key.Key and swap A/B and X/Y.

Here's a function doing that (untested)

#include "imgui_internal.h"

void ImGui_ImplSwitch_SwapABXY(int start_event)
{
    auto& input_queue = ImGui::GetCurrentContext()->InputEventsQueue;

    for (int n = start_event; n < input_queue.Size; n++)
    {
        ImGuiInputEvent& e = input_queue[n];
        if (e.Type == ImGuiInputEventType_Key)
        {
            switch (e.Key.Key)
            {
            case ImGuiKey_GamepadFaceLeft:  e.Key.Key = ImGuiKey_GamepadFaceUp; break;   // X<>Y
            case ImGuiKey_GamepadFaceUp:    e.Key.Key = ImGuiKey_GamepadFaceLeft; break;
            case ImGuiKey_GamepadFaceRight: e.Key.Key = ImGuiKey_GamepadFaceDown; break;   // X<>B
            case ImGuiKey_GamepadFaceDown:  e.Key.Key = ImGuiKey_GamepadFaceRight; break;
            }
        }
    }
}

Usage:

// Start the Dear ImGui frame
const int input_queue_size_before = ImGui::GetCurrentContext()->InputEventsQueue.Size;
ImGui_ImplDX11_NewFrame();
ImGui_ImplWin32_NewFrame();

// Call between backend and main lib NewFrame():
ImGui_ImplSwitch_SwapABXY(input_queue_size_before);

ImGui::NewFrame();

Thanks for the suggestion, I'm doing it this way now. It also seems to be fine now with SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE it might've been an issue with something else we were doing early on in supporting the Switch. SDL_GetCurrentVideoDriver () is reporting Switch.

Looks like all is working well! In case its still useful using the latest SDL from devKitPro

[dcvz]

I finally ended up getting this into our production. Unfortunately doing the swap in this manner messed with NavEnableGamepad. I’m exploring now the option of redefining what ImGui uses.

If you happen to have any other suggestions I’d appreciate it! Would be good to have a good sign off to guide the work in case it’s something that’s useful to upstream.

[ocornut]

Unfortunately doing the swap in this manner messed with NavEnableGamepad.

Can you clarify?

[dcvz]

Unfortunately doing the swap in this manner messed with NavEnableGamepad.

Can you clarify?

Yeah.. still digging but essentially: doing a swap in this way is messing with the ability of navigating via gamepad buttons. It now seems to only handle the first button press then nothing more.

Before we were doing it in sdl_impl:

    #ifdef __SWITCH__
    MAP_BUTTON(ImGuiKey_GamepadFaceDown,        SDL_CONTROLLER_BUTTON_B);              // Xbox A, PS Cross
    MAP_BUTTON(ImGuiKey_GamepadFaceRight,       SDL_CONTROLLER_BUTTON_A);              // Xbox B, PS Circle
    MAP_BUTTON(ImGuiKey_GamepadFaceLeft,        SDL_CONTROLLER_BUTTON_Y);              // Xbox X, PS Square
    MAP_BUTTON(ImGuiKey_GamepadFaceUp,          SDL_CONTROLLER_BUTTON_X);              // Xbox Y, PS Triangle
    #else

My guess is that it’s the difference between changing the definition itself vs swapping the button press — but still trying to find a better working solution.

[dcvz]

Ok, can confirm that this instead still has gamepad navigation working: (doing this just if platform is SWITCH)

#define ImGuiKey_NavGamepadActivate     ImGuiKey_GamepadFaceRight
#define ImGuiKey_NavGamepadCancel       ImGuiKey_GamepadFaceDown
#define ImGuiKey_NavGamepadMenu         ImGuiKey_GamepadFaceUp
#define ImGuiKey_NavGamepadInput        ImGuiKey_GamepadFaceLeft

then changing imgui_internal to do:

#ifndef ImGuiKey_NavGamepadActivate
#define ImGuiKey_NavGamepadActivate     ImGuiKey_GamepadFaceDown
#endif

#ifndef ImGuiKey_NavGamepadCancel
#define ImGuiKey_NavGamepadCancel       ImGuiKey_GamepadFaceRight
#endif

#ifndef ImGuiKey_NavGamepadMenu
#define ImGuiKey_NavGamepadMenu         ImGuiKey_GamepadFaceLeft
#endif

#ifndef ImGuiKey_NavGamepadInput
#define ImGuiKey_NavGamepadInput        ImGuiKey_GamepadFaceUp
#endif

Would you like me to PR something like this @ocornut ? and if so, should all properties be able to be overwritten?

[ocornut]

This is not the right solution, you should be able swap the buttons in the InputQueue using code similar to what I provided:
#5723 (comment)
If you don't you'll need to dig into it.

[dcvz]

This is not the right solution, you should be able swap the buttons in the InputQueue using code similar to what I provided:
#5723 (comment)
If you don't you'll need to dig into it.

Yeah, this is what I had originally. But here, if I understand correctly we’re basically just replacing the button press.

The code in ImGui for game pad navigation is specifically looking for ImGuiKey_NavGamepadInput and friends. Swapping button presses won’t trigger that input then right?

[ocornut]

ImGuiKey_NavGamepadInput is defined to ImGuiKey_GamepadFaceLeft so if you swap _Left to something else it'll work.

[dcvz]

ImGuiKey_NavGamepadInput is defined to ImGuiKey_GamepadFaceLeft so if you swap _Left to something else it'll work.

It doesn’t for some reason. None of the buttons trigger navigation. I’ll try to dig into it later.. technically I have two solutions that work, but was aiming to do it without modifying ImGui. I’ll see if I can get the example project setup with the reproduction.

[ocornut]

My solution doesn't modify dear imgui, and I can't comprehend how it would not work, it's a very simple thing just swapping buttons after the backend submitted them. You'll have to focus on getting this working or understanding why it doesn't.

[ocornut]

@dcvz Did you get to the bottom of that? I was thinking that I may understand why would attempt may be broken: if you have a function doing a single replacement and calling this function multiple times, one remap would lead to another. Note how my own does all the replacements in the same spot.

Also note that since 1.89.5 we have added ImU32 EventID field to ImGuiInputEvent which is an always increasing unique number per event. You may use that as a way to track which event to modify in the queue (versus my approach below of reading InputEventsQueue.Size before and after the backend NewFrame calls, but both will work).

[ocornut]

I have now added a runtime option io.ConfigNavSwapGamepadButtons to swap the A<>B (cancel<>activate) button behaviors for navigation at a higher level, see b3ba6b3

But I was wondering why did you also need to swap X<>Y ?