Wrap game viewport with custom widget

Development Pipeline & Plugins
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1

Hi,

Right now the only way to add widgets to viewport is to use AddViewportWidget (or similar) function but it just adds a widget on top of the viewport. I was wondering if one could wrap game viewport with custom widget?

So what I would like to achieve is something like in Heroes of Might&Magic. https://lh3.ggpht.com/pVricu4a1S63c3fXk6hcU7s0ykd8pfpHYd5h2VSKi2vG1TqFVP7Fq2uT-vyXiHd1FQ=h900

I want game viewport to be a part of panel widget so I can surround it with other widgets. I dont want these other widgets to cover my viewport.

So for the testing purposes I managed to modify PlayLevel.cpp and change this line

PieWindow->SetContent( PieViewportWidget.ToSharedRef() );

so it looks like this:

PieWindow->SetContent( SNew(SHorizontalBox)
					+SHorizontalBox::Slot()[SNullWidget::NullWidget]
					+SHorizontalBox::Slot()[PieViewportWidget.ToSharedRef()] );

The result was just what I expected ( http://i.imgur.com/dK1N4o2.png ) but this will work only for Play in New Editor Window option. What I want is to have same effect in standalone game.

So I modified GameEngine.cpp and change GameViewportWindowPtr->SetContent( line like this

GameViewportWindowPtr->SetContent(SNew(SHorizontalBox)
			+ SHorizontalBox::Slot()[SNullWidget::NullWidget]
			+ SHorizontalBox::Slot()[GameViewportWidgetRef] );

But the result was quite different than expected: http://i.imgur.com/XcNppyf.png There are now 2 viewports, one on top of the other and I cant really figure out why is that.

I was thinking that maybe it could be possible to add a function like

virtual TSharedRef<SWidget> GetGameViewportWidget(TSharedRef<SWidget> ViewportWidget);

that would allow user to wrap viewport with any widget he/she wants. So if you would like to not wrap viewport with anything you would just return ViewportWidget; but if you would like to wrap viewport with horizontal box (like in the examples above) you would

return SNew(SHorizontalBox)
    + SHorizontalBox::Slot()[SNullWidget::NullWidget]
    + SHorizontalBox::Slot()[ViewportWidget];

How difficult would it be to implement such a functionality? GameWindow creation code is kinda scattered (between editor and game engine) and complex, so before I start doing anything I would like to ask if this kind of engine modification wont cause too much complications? How much code will I have to adjust to get this thing working?

I also have no idea where this kind of function should be implemented. GameEngine? EditorEngine? maybe GameInstance or GameMode?

Any tips and thoughts appreciated,
Thanks

2

Anyone ? ?

3

still looking for any tips

4

I have searched a long time to find a solution for this.
The only way I could come up to solve this is by abusing the splitscreen functionality. Splitscreens don’t have to be enabled in the settings for this to work. Use the following C++ code:

Imagine you have a widget on the left side and call the following function inside a ticking function (I put this inside the DrawHUD overridden function)

if (!bGameViewportAdjusted)
{
  AdjustGameViewport();
}

This ensures that the size of the viewport and its origin will be adjusted once the viewport actually finished initializing (this is usually done with a small delay, which I find very very unelegant and unreliable too but do this as you please).

void YourHUDClass::AdjustGameViewport() const
{
  if (GetWorld() && GetWorld()->WorldType == EWorldType::Game
&& GEngine && GEngine->GameViewport)
  {
    FVector2D ViewportSize;
    GEngine->GameViewport->GetViewportSize(ViewportSize);
    
    // The GameViewport takes some time to initialize
    if (ViewportSize.X > 0 && ViewportSize.Y > 0)
    {
      LeftSideUISize = LeftSideUIWidget->GetDesiredSize();

      // HACK: This "transforms" slate space to screen space
      LeftSideUISize = LeftSideUISize / (FVector2D(1920, 1080) / ViewportSize);

      FVector2D LeftSideUISizeRelativeToViewport = LeftSideUISize / ViewportSize;

      GEngine->GameViewport->SplitscreenInfo[0].PlayerData[0].OriginX = LeftSideUISizeRelativeToViewport.X;
      GEngine->GameViewport->SplitscreenInfo[0].PlayerData[0].OriginY = 0.0f;
      GEngine->GameViewport->SplitscreenInfo[0].PlayerData[0].SizeX   = 1.0f - LeftSideUISizeRelativeToViewport.X; 
      GEngine->GameViewport->SplitscreenInfo[0].PlayerData[0].SizeY   = 1.0f;

      bGameViewportAdjusted = true;
    }
  }
}

If you would like to add a slate widget to the top you can do this the same way with

GEngine->GameViewport->SplitscreenInfo[0].PlayerData[0].OriginY = TopSideUISizeRelativeToViewport.Y; 
GEngine->GameViewport->SplitscreenInfo[0].PlayerData[0].SizeY    = 1.0f - LeftSideUISizeRelativeToViewport.Y;

If you want to add a slate widget to the right you have to subtract the X size of that widget from SizeX, and if you want to add a slate widget to the bottom you have to subtract the Y size of that widget from SizeY (additionaly to what you already subtract for left and top).

If you’ve noticed I am only doing this when it is not PIE (GetWorld() && GetWorld()->WorldType == WorldType::Game). I couldn’t figure out yet how to calculate the Widget size correctly for PIE.

5

Hi, szyszek
I have same issue. PIE is ok, but standalone game not work.
Did you figured it out how to do?
Thanks.

6

Not sure it will work out but in GameEngine.cpp there is this line saying to render directly to the window buffer:
.RenderDirectlyToWindow(bRenderDirectlyToWindow)

Maybe by putting false there it could work.
Here an example for doing that somewhere in your code after the ViewportWidget initialization.

UGameEngine* GameEngine = Cast<UGameEngine>(GEngine);

if (GameEngine != nullptr)
{
	TSharedPtr<SViewport> ViewportWidget = GameEngine->GetGameViewportWidget();
	if (ViewportWidget.IsValid())
	{
		ViewportWidget->SetRenderDirectlyToWindow(false);
	}
}