---
title: UE4 Gameplay Debug技巧
date: 2022-12-09 11:30:54
excerpt: Debug
tags: 
rating: ⭐
---
## debug技巧
### 在release模式下开启断点的方法
如果要debug代码可以用一个非常古典的办法用
`#pragma optimize("",off)` 与`#pragma optimize("",on)` 来将一部分代码排除在优化以外

### Ue4中的可视化debug法——vlog
http://api.unrealengine.com/CHN/Gameplay/Tools/VisualLogger/index.html
实现GrabDebugSnapshot接口，之后调用UE_VLOG()宏。
```c++
#if ENABLE_VISUAL_LOG
    /** Appends information about this actor to the visual logger */
    virtual void GrabDebugSnapshot(FVisualLogEntry* Snapshot) const override;
#endif
#if ENABLE_VISUAL_LOG
void AGDCCharacter::GrabDebugSnapshot(FVisualLogEntry* Snapshot) const
{
    Super::GrabDebugSnapshot(Snapshot);
    const int32 CatIndex = Snapshot->Status.AddZeroed();
    FVisualLogStatusCategory& PlaceableCategory = Snapshot->Status[CatIndex];
    PlaceableCategory.Category = TEXT("GDC Sample");
    PlaceableCategory.Add(TEXT("Projectile Class"), ProjectileClass != nullptr ? ProjectileClass->GetName() : TEXT("None"));
}
#endif
void AGDCCharacter::OnFire()
{
    // try and fire a projectile
    if (ProjectileClass != NULL)
    {
        const FRotator SpawnRotation = GetControlRotation();
        // MuzzleOffset is in camera space, so transform it to world space before offsetting from the character location to find the final muzzle position
        const FVector SpawnLocation = GetActorLocation() + SpawnRotation.RotateVector(GunOffset);
        UWorld* const World = GetWorld();
        if (World != NULL)
        {
            // spawn the projectile at the muzzle
            World->SpawnActor<AGDCProjectile>(ProjectileClass, SpawnLocation, SpawnRotation);
            UE_VLOG(this, LogFPChar, Verbose, TEXT("Fired projectile (%s) from location (%s) with rotation (%s)"),
                *ProjectileClass->GetName(),
                *SpawnLocation.ToString(),
                *SpawnRotation.ToString());
        }
    }
    // try and play the sound if specified
    if (FireSound != NULL)
    {
        UGameplayStatics::PlaySoundAtLocation(this, FireSound, GetActorLocation());
    }
    // try and play a firing animation if specified
    if(FireAnimation != NULL)
    {
        // Get the animation object for the arms mesh
        UAnimInstance* AnimInstance = Mesh1P->GetAnimInstance();
        if(AnimInstance != NULL)
        {
            AnimInstance->Montage_Play(FireAnimation, 1.f);
        }
    }
}
```
之后就可以在visual logger里看到实时数据。除此之外还有一些可视的形状log：
1. UE_VLOG_SEGMENT
2. UE_VLOG_LOCATION
3. UE_VLOG_BOX (axis aligned box)
4. UE_VLOG_OBOX (oriented box)
5. UE_VLOG_CONE
6. UE_VLOG_CYLINDER
7. UE_VLOG_CAPSULE