转自:http://aigo.iteye.com/blog/2272698

代码还是参考自Epic官方的塔防项目:StrategyGame

看了下C++的API,现成的API中貌似只支持单点触碰检测,用法如下:
注册:

// support touch devices
InputComponent->BindTouch(EInputEvent::IE_Pressed, this, &ATD_MobilePlayerController::MoveToTouchLocation);
InputComponent->BindTouch(EInputEvent::IE_Repeat, this, &ATD_MobilePlayerController::MoveToTouchLocation);

触发回调:

void ATD_MobilePlayerController::MoveToTouchLocation(const ETouchIndex::Type FingerIndex, const FVector Location)
{
FVector2D ScreenSpaceLocation(Location); // Trace to see what is under the touch location
FHitResult HitResult;
GetHitResultAtScreenPosition(ScreenSpaceLocation, CurrentClickTraceChannel, true, HitResult);
if (HitResult.bBlockingHit)
{
// We hit something, move there
SetNewMoveDestination(HitResult.ImpactPoint);
}
}

如果要实现多点触碰检测,比如实现两个手指捏动来缩放屏幕,StrategyGame项目自己实现了一套算法来实现多点屏幕检测,具体做法如下:
StrategyPlayerController.h

1,先重写StrategyPlayerController的ProcessPlayerInput()和SetupInputComponent()函数

protected:
/** update input detection */
virtual void ProcessPlayerInput(const float DeltaTime, const bool bGamePaused) override;
virtual void SetupInputComponent() override;

在SetupInputComponent()函数中绑定事件(这个事件机制也是自己写的),其中BIND_1P_ACTION和BIND_2P_ACTION是自己定义的宏:

ProcessPlayerInput()来检测触碰点变化,这是一个连续执行的函数,大概逻辑是:每次执行时都会把当前的屏幕触碰信息和上次的触碰信息做对比,检测是单点触碰,还是按住不放,还是多点触碰或多点按住不放等等,具体逻辑在InputHandler->UpdateDetection(DeltaTime);中。

void AStrategyPlayerController::ProcessPlayerInput(const float DeltaTime, const bool bGamePaused)
{
if (!bGamePaused && PlayerInput && InputHandler && !bIgnoreInput)
{
InputHandler->UpdateDetection(DeltaTime);
} Super::ProcessPlayerInput(DeltaTime, bGamePaused); if (!bIgnoreInput )
{
const ULocalPlayer* LocalPlayer = Cast<ULocalPlayer>(Player);
AStrategySpectatorPawn* StrategyPawn = GetStrategySpectatorPawn();
if(( StrategyPawn != NULL ) && ( LocalPlayer != NULL ))
{
// Create the bounds for the minimap so we can add it as a 'no scroll' zone.
AStrategyHUD* const HUD = Cast<AStrategyHUD>(GetHUD());
AStrategyGameState const* const MyGameState = GetWorld()->GetGameState<AStrategyGameState>();
if( (MyGameState != NULL ) && ( MyGameState->MiniMapCamera.IsValid() == true ) )
{
if( LocalPlayer->ViewportClient != NULL )
{
const FIntPoint ViewportSize = LocalPlayer->ViewportClient->Viewport->GetSizeXY();
const uint32 ViewTop = FMath::TruncToInt(LocalPlayer->Origin.Y * ViewportSize.Y);
const uint32 ViewBottom = ViewTop + FMath::TruncToInt(LocalPlayer->Size.Y * ViewportSize.Y); FVector TopLeft( HUD->MiniMapMargin, ViewBottom - HUD->MiniMapMargin - MyGameState->MiniMapCamera->MiniMapHeight, );
FVector BottomRight( (int32)MyGameState->MiniMapCamera->MiniMapWidth, MyGameState->MiniMapCamera->MiniMapHeight, );
FBox MiniMapBounds( TopLeft, TopLeft + BottomRight );
StrategyPawn->GetStrategyCameraComponent()->AddNoScrollZone( MiniMapBounds );
StrategyPawn->GetStrategyCameraComponent()->UpdateCameraMovement( this );
}
}
}
}
}

StrategyInput.cpp

05-08 08:14