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03-UnrealEngine/Gameplay/Debug/UE4 Gameplay Debug技巧.md

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+---
+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