Here's a neat trick in CMake: you want to change the name of a variable, but worry that anyone you've distributed the code to already will lose the option they've selected.
Use the old variable as the default value for the new one:
option(OLD_VARIABLE "Some variable" ON)
option(NEW_VARIABLE "Some variable" ${OLD_VARIABLE})
or...
set( OLD_STRING_VARIABLE "Old default" CACHE STRING "Help text" )set( NEW_STRING_VARIABLE "${OLD_STRING_VARIABLE}" "Help text" )
To pass an array of structs from C++ to C#, you can pass a pointer to a C-style array. In C++ you may have a struct, e.g.
#pragma pack(push)
#pragma pack(1)
struct InputEvent
{
uint32_t eventId;
float floatValue;
uint32_t intValue;
};
#pragma pack(pop)
The delegate in C++ is:
typedef void(__stdcall* ProcessNewInputFn) (int numEvents, const InputEvent**);
Telling C++ what C# function to call:
extern "C" __declspec(dllexport) void SetInputProcessingDelegate(ProcessNewInputFn newInputProcessing)
{
processNewInput = newInputProcessing;
}
Using this from C++
std::vector<InputEvent> inputEvents;
const avs::InputEvent *v=inputEvents.data();
processNewInput(inputEvents.size(), &v);
In C# the struct is defined as:
[StructLayout(LayoutKind.Sequential, Pack = 1)]
public struct InputEvent
{
public UInt32 eventId;
public float floatValue;
public UInt32 intValue;
};
Note the packing! It must match what we had in C++. Now C# must declare the the delegate type it will implement:
[UnmanagedFunctionPointer(CallingConvention.StdCall)]
delegate void OnNewInput(int numEvents, in IntPtr newEvents);
And declare in C# the C++ function that sets the delegate:
[DllImport("dllname")]
static extern void SetInputProcessingDelegate(OnNewInput onNewInput );
This is called with
ok = SetInputProcessingDelegate(ProcessingClass.SetInput);
Where we have a class like this:
class ProcessingClass
{
public static void StaticProcessInput(int numEvents, in IntPtr inputEventsPtr )
{
int EventSize = System.Runtime.InteropServices.Marshal.SizeOf(typeof(avs.InputEvent));
avs.InputEvent[] inputEvents = new avs.InputEvent[inputState.numEvents];
IntPtr ptr= inputEventsPtr;
for (int i = 0; i < inputState.numEvents; i++)
{
inputEvents[i]=Marshal.PtrToStructure<avs.InputEvent>(ptr);
ptr += EventSize;
}
}
}
Here, we take the C++ style pointer-to-array, and iterate through the array elements, copying each in turn into the C# style array.
#define S_DECLARE_CHECKBOX(name) \
bool name; \
ECheckBoxState Is##name##Checked() const { return name ? ECheckBoxState::Checked:ECheckBoxState::Unchecked;} \
void On##name##Changed(ECheckBoxState InCheckedState) {name=(InCheckedState==ECheckBoxState::Checked);}
class STrueSkySetupTool : public SCompoundWidget
{
public:
SLATE_BEGIN_ARGS( STrueSkySetupTool )
:_CreateTrueSkyLight(false)
,_DirectionalLight(nullptr)
,_CreateDirectionalLight(nullptr)
,_Sequence(nullptr)
{}
/** A TrueSkyLight actor performs real-time ambient lighting.*/
SLATE_ARGUMENT(bool,CreateTrueSkyLight)
/** TrueSKY can drive a directional light to provide sunlight and moonlight.*/
SLATE_ARGUMENT(ADirectionalLight*,DirectionalLight)
/** If there's no directional light in the scene, you can create one with this checkbox.*/
SLATE_ARGUMENT(bool,CreateDirectionalLight)
/** The TrueSKY Sequence provides the weather state to render.*/
SLATE_ARGUMENT(UTrueSkySequenceAsset *,Sequence)
/** Event called when code is successfully added to the project */
SLATE_EVENT( FOnTrueSkySetup, OnTrueSkySetup )
SLATE_END_ARGS()
/** Constructs this widget with InArgs */
void Construct( const FArguments& InArgs );
/** Handler for when cancel is clicked */
void CancelClicked();
/** Returns true if Finish is allowed */
bool CanFinish() const;
/** Handler for when finish is clicked */
void FinishClicked();
...
S_DECLARE_CHECKBOX(CreateTrueSkyLight)
S_DECLARE_CHECKBOX(ShowAllSequences)
void SetupSequenceAssetItems();
void CloseContainingWindow();
private:
/** The wizard widget */
TSharedPtr<SWizard> MainWizard;
FOnTrueSkySetup OnTrueSkySetup;
...
};
TSharedRef<STrueSkySetupTool> TrueSkySetupTool = SNew(STrueSkySetupTool).OnTrueSkySetup(OnTrueSkySetup1).CreateTrueSkyLight(true);
FOnTrueSkySetup OnTrueSkySetupDelegate;3. Create a window for the widget. This function is called when the menu option to start the wizard is selected:
void FTrueSkyEditorPlugin::OnAddSequence()
{
TrueSkySetupWindow = SNew(SWindow)
.Title( NSLOCTEXT("InitializeTrueSky", "WindowTitle", "Initialize trueSKY") )
.ClientSize( FVector2D(600, 550) )
.SizingRule( ESizingRule::FixedSize )
.SupportsMinimize(false).SupportsMaximize(false);
OnTrueSkySetupDelegate.BindRaw(this,&FTrueSkyEditorPlugin::OnTrueSkySetup);
TSharedRef TrueSkySetupTool = SNew(STrueSkySetupTool).OnTrueSkySetup(OnTrueSkySetupDelegate);
TrueSkySetupWindow->SetContent( TrueSkySetupTool );
TSharedPtr< SWindow > ParentWindow;
if( FModuleManager::Get().IsModuleLoaded( "MainFrame" ) )
{
IMainFrameModule& MainFrame = FModuleManager::GetModuleChecked<imainframemodule>( "MainFrame" );
ParentWindow = MainFrame.GetParentWindow();
}
bool modal=false;
if (modal)
{
FSlateApplication::Get().AddModalWindow(TrueSkySetupWindow.ToSharedRef(), ParentWindow);
}
else if (ParentWindow.IsValid())
{
FSlateApplication::Get().AddWindowAsNativeChild(TrueSkySetupWindow.ToSharedRef(), ParentWindow.ToSharedRef());
}
else
{
FSlateApplication::Get().AddWindow(TrueSkySetupWindow.ToSharedRef());
}
TrueSkySetupWindow->ShowWindow();
}
4. Implement the setup tool:
BEGIN_SLATE_FUNCTION_BUILD_OPTIMIZATION
void STrueSkySetupTool::Construct( const FArguments& InArgs )
{
OnTrueSkySetup = InArgs._OnTrueSkySetup;
CreateTrueSkyLight=InArgs._CreateTrueSkyLight;
DirectionalLight=InArgs._DirectionalLight;
Sequence=InArgs._Sequence;
...
The interface to build the actual UI is really interesting. By overloading the [] and + operators, Epic lets you specify the widget structure like so:
ChildSlot
[
SNew(SBorder)
.Padding(18)
.BorderImage( FEditorStyle::GetBrush("Docking.Tab.ContentAreaBrush") )
[
SNew(SVerticalBox)
+SVerticalBox::Slot()
[
SAssignNew( MainWizard, SWizard)
.ShowPageList(false)
.CanFinish(this, &STrueSkySetupTool::CanFinish)
.FinishButtonText( LOCTEXT("TrueSkyFinishButtonText", "Initialize") )
.OnCanceled(this, &STrueSkySetupTool::CancelClicked)
.OnFinished(this, &STrueSkySetupTool::FinishClicked)
.InitialPageIndex( 0)
+SWizard::Page()
[
SNew(SVerticalBox)
+SVerticalBox::Slot()
.AutoHeight()
[
SNew(STextBlock)
.TextStyle( FEditorStyle::Get(), "NewClassDialog.PageTitle" )
.Text( LOCTEXT( "WeatherStateTitle", "Choose a Sequence Asset" ) )
]
+SVerticalBox::Slot()
.AutoHeight()
.Padding(0)
[
SNew(SHorizontalBox)
+SHorizontalBox::Slot()
.FillWidth(1.f)
.VAlign(VAlign_Center)
[
SNew(STextBlock)
.Text(LOCTEXT("TrueSkySetupToolDesc", "Choose which weather sequence to use initially.") )
.AutoWrapText(true)
.TextStyle(FEditorStyle::Get(), "NewClassDialog.ParentClassItemTitle")
]
]
]
+SWizard::Page()
[
...
]
]
]
];
}
void FTrueSkyEditorPlugin::OnTrueSkySetup(bool CreateDirectionalLight, ADirectionalLight* DirectionalLight,bool CreateTrueSkyLight,UTrueSkySequenceAsset *Sequence)
{
...
}
"path to MSBuild.exe" /t:Engine\UE4 /p:Configuration="Development Editor" /p:Platform=Win64 UE4.sln