UE4引擎分析-射线碰撞检测、玩家输入后处理

1、碰撞检测 UKismetSystemLibrary::LineTraceSingle

Ray-Trace作用于射线拾取。

射线拾取主要相关 
1.拾取函数是UWorld的多个方法。比如LineTraceSingle是单一拾取，拾取到一个之后就不继续穿透了，而LineTraceMulti会拾取多个目标。 

bool UKismetSystemLibrary::LineTraceSingle(UObject* WorldContextObject, const FVector Start, const FVector End, ETraceTypeQuery TraceChannel, bool bTraceComplex, const TArray<AActor*>& ActorsToIgnore, EDrawDebugTrace::Type DrawDebugType, FHitResult& OutHit, bool bIgnoreSelf, FLinearColor TraceColor, FLinearColor TraceHitColor, float DrawTime)

{

    ECollisionChannel CollisionChannel = UEngineTypes::ConvertToCollisionChannel(TraceChannel);



    static const FName LineTraceSingleName(TEXT("LineTraceSingle"));

    FCollisionQueryParams Params = ConfigureCollisionParams(LineTraceSingleName, bTraceComplex, ActorsToIgnore, bIgnoreSelf, WorldContextObject);



    UWorld* World = GEngine->GetWorldFromContextObject(WorldContextObject);

    bool const bHit = World->LineTraceSingleByChannel(OutHit, Start, End, CollisionChannel, Params);



#if ENABLE_DRAW_DEBUG

    DrawDebugLineTraceSingle(World, Start, End, DrawDebugType, bHit, OutHit, TraceColor, TraceHitColor, DrawTime);

#endif



    return bHit;

}



bool UKismetSystemLibrary::LineTraceMulti(UObject* WorldContextObject, const FVector Start, const FVector End, ETraceTypeQuery TraceChannel, bool bTraceComplex, const TArray<AActor*>& ActorsToIgnore, EDrawDebugTrace::Type DrawDebugType, TArray<FHitResult>& OutHits, bool bIgnoreSelf, FLinearColor TraceColor, FLinearColor TraceHitColor, float DrawTime)

{

    ECollisionChannel CollisionChannel = UEngineTypes::ConvertToCollisionChannel(TraceChannel);



    static const FName LineTraceMultiName(TEXT("LineTraceMulti"));

    FCollisionQueryParams Params = ConfigureCollisionParams(LineTraceMultiName, bTraceComplex, ActorsToIgnore, bIgnoreSelf, WorldContextObject);



    UWorld* World = GEngine->GetWorldFromContextObject(WorldContextObject);

    bool const bHit = World->LineTraceMultiByChannel(OutHits, Start, End, CollisionChannel, Params);



#if ENABLE_DRAW_DEBUG

    DrawDebugLineTraceMulti(World, Start, End, DrawDebugType, bHit, OutHits, TraceColor, TraceHitColor, DrawTime);

#endif



    return bHit;

}

2、玩家输入处理
 

void APlayerController::PostProcessInput(const float DeltaTime, const bool bGamePaused)

{

    if( IsLookInputIgnored() )

    {

        // zero look inputs

        RotationInput = FRotator::ZeroRotator;

    }

}

匹配字符串：40 53 48 83 EC 20 48 8B 01 48 8B D9 FF 90 00 07 00 00 84 C0 74 1C F2 0F

.text:00007FF6F7D7A4F0                         sub_7FF6F7D7A4F0 proc near              ; DATA XREF: .rdata:00007FF6F9856A78↓o
.text:00007FF6F7D7A4F0                                                                 ; .rdata:00007FF6F9C67D40↓o
.text:00007FF6F7D7A4F0                                                                 ; .pdata:00007FF6FA4A2460↓o
.text:00007FF6F7D7A4F0 40 53                                   push    rbx
.text:00007FF6F7D7A4F2 48 83 EC 20                             sub     rsp, 20h
.text:00007FF6F7D7A4F6 48 8B 01                                mov     rax, [rcx]
.text:00007FF6F7D7A4F9 48 8B D9                                mov     rbx, rcx
.text:00007FF6F7D7A4FC FF 90 00 07 00 00                       call    qword ptr [rax+700h]
.text:00007FF6F7D7A502 84 C0                                   test    al, al
.text:00007FF6F7D7A504 74 1C                                   jz      short loc_7FF6F7D7A522
.text:00007FF6F7D7A506 F2 0F 10 05 9A E0 3F 02                 movsd   xmm0, cs:qword_7FF6FA1785A8
.text:00007FF6F7D7A50E F2 0F 11 83 88 05 00 00                 movsd   qword ptr [rbx+588h], xmm0
.text:00007FF6F7D7A516 8B 05 94 E0 3F 02                       mov     eax, cs:dword_7FF6FA1785B0
.text:00007FF6F7D7A51C 89 83 90 05 00 00                       mov     [rbx+590h], eax
.text:00007FF6F7D7A522
.text:00007FF6F7D7A522                         loc_7FF6F7D7A522:                       ; CODE XREF: sub_7FF6F7D7A4F0+14↑j
.text:00007FF6F7D7A522 48 83 C4 20                             add     rsp, 20h
.text:00007FF6F7D7A526 5B                                      pop     rbx
.text:00007FF6F7D7A527 C3                                      retn
.text:00007FF6F7D7A527                         sub_7FF6F7D7A4F0 endp



__int64 __fastcall sub_7FF6F7D7A4F0(__int64 a1)
{
  __int64 result; // rax

  result = (*(__int64 (__fastcall **)(__int64))(*(_QWORD *)a1 + 1792i64))(a1);
  if ( (_BYTE)result )
  {
    *(_QWORD *)(a1 + 1416) = qword_7FF6FA1785A8;
    result = (unsigned int)dword_7FF6FA1785B0;
    *(_DWORD *)(a1 + 1424) = dword_7FF6FA1785B0;
  }
  return result;
}