UE5 crashing when spawning projectile

General Issues and Bug Reporting
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1

Hello,

Currently, I am working on some things in a course for college. I’ve been trying to get this to work for hours on end and can’t seem to fix the issue. Basically, I need to randomize the color of the projectile and have it be the same color as the randomized decal. I also need the decal to spawn with a randomized frame. The decal has 4 frames. I will attach the error code, the projectile BP, and the code below. Also, as added detail, I am working from the UE5 FPS template without starter content.
This is the error code I receive when trying to fire the weapon.

Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x0000000000000000

UnrealEditor_FPS415_5024!AFPS415Projectile::BeginPlay() [D:\UnrealGames\FPS415\Source\FPS415\FPS415Projectile.cpp:47]
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_FPS415_5024!UTP_WeaponComponent::Fire() [D:\UnrealGames\FPS415\Source\FPS415\TP_WeaponComponent.cpp:47]
UnrealEditor_FPS415_5024!TBaseUObjectMethodDelegateInstance<0,UTP_WeaponComponent,void __cdecl(void),FDefaultDelegateUserPolicy>::Execute() [D:\Epic Games\UE_5.4\Engine\Source\Runtime\Core\Public\Delegates\DelegateInstancesImpl.h:650]
UnrealEditor_FPS415_5024!FEnhancedInputActionEventDelegateBinding<TDelegate<void __cdecl(void),FDefaultDelegateUserPolicy> >::Execute() [D:\Epic Games\UE_5.4\Engine\Plugins\EnhancedInput\Source\EnhancedInput\Public\EnhancedInputComponent.h:303]
UnrealEditor_EnhancedInput
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_Core
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor_Engine
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
kernel32
ntdll

Next is the Projectile header file.

// Copyright Epic Games, Inc. All Rights Reserved.

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "FPS415Projectile.generated.h"

class USphereComponent;
class UProjectileMovementComponent;

UCLASS(config=Game)
class AFPS415Projectile : public AActor
{
	GENERATED_BODY()

	/** Sphere collision component */
	UPROPERTY(VisibleDefaultsOnly, Category=Projectile)
	USphereComponent* CollisionComp;

	/** Projectile movement component */
	UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category = Movement, meta = (AllowPrivateAccess = "true"))
	UProjectileMovementComponent* ProjectileMovement;

	UPROPERTY(EditAnywhere)
		UStaticMeshComponent* ballMesh;

	UPROPERTY(EditAnywhere)
		UMaterial* baseMat;

	UPROPERTY()
		FLinearColor randColor;

	UPROPERTY(EditAnywhere)
	UMaterialInterface* projMat;

	UPROPERTY()
	UMaterialInstanceDynamic* dmiMat;

public:
	AFPS415Projectile();

protected:
	virtual void BeginPlay();

public:
	/** called when projectile hits something */
	UFUNCTION()
	void OnHit(UPrimitiveComponent* HitComp, AActor* OtherActor, UPrimitiveComponent* OtherComp, FVector NormalImpulse, const FHitResult& Hit);

	/** Returns CollisionComp subobject **/
	USphereComponent* GetCollisionComp() const { return CollisionComp; }
	/** Returns ProjectileMovement subobject **/
	UProjectileMovementComponent* GetProjectileMovement() const { return ProjectileMovement; }
};

This is the C++ file

// Copyright Epic Games, Inc. All Rights Reserved.

#include "FPS415Projectile.h"
#include "GameFramework/ProjectileMovementComponent.h"
#include "Kismet/KismetMathLibrary.h"
#include "Components/SphereComponent.h"
#include "Components/DecalComponent.h"
#include "Kismet/GameplayStatics.h"

AFPS415Projectile::AFPS415Projectile() 
{
	// Use a sphere as a simple collision representation
	CollisionComp = CreateDefaultSubobject<USphereComponent>(TEXT("SphereComp"));
	CollisionComp->InitSphereRadius(5.0f);
	CollisionComp->BodyInstance.SetCollisionProfileName("Projectile");
	CollisionComp->OnComponentHit.AddDynamic(this, &AFPS415Projectile::OnHit);		// set up a notification for when this component hits something blocking

	// Players can't walk on it
	CollisionComp->SetWalkableSlopeOverride(FWalkableSlopeOverride(WalkableSlope_Unwalkable, 0.f));
	CollisionComp->CanCharacterStepUpOn = ECB_No;

	ballMesh = CreateDefaultSubobject<UStaticMeshComponent>("Ball Mesh");

	// Set as root component
	RootComponent = CollisionComp;

	ballMesh->SetupAttachment(CollisionComp);

	// Use a ProjectileMovementComponent to govern this projectile's movement
	ProjectileMovement = CreateDefaultSubobject<UProjectileMovementComponent>(TEXT("ProjectileComp"));
	ProjectileMovement->UpdatedComponent = CollisionComp;
	ProjectileMovement->InitialSpeed = 3000.f;
	ProjectileMovement->MaxSpeed = 3000.f;
	ProjectileMovement->bRotationFollowsVelocity = true;
	ProjectileMovement->bShouldBounce = true;

	// Die after 3 seconds by default
	InitialLifeSpan = 3.0f;
}

void AFPS415Projectile::BeginPlay()
{
	Super::BeginPlay();
	randColor = FLinearColor(UKismetMathLibrary::RandomFloatInRange(0.f, 1.f), UKismetMathLibrary::RandomFloatInRange(0.f, 1.f), UKismetMathLibrary::RandomFloatInRange(0.f, 1.f), 1.f);

	dmiMat = UMaterialInstanceDynamic::Create(projMat, this);
	ballMesh->SetMaterial(0, dmiMat);

	dmiMat->SetVectorParameterValue("ProjColor", randColor);
}


void AFPS415Projectile::OnHit(UPrimitiveComponent* HitComp, AActor* OtherActor, UPrimitiveComponent* OtherComp, FVector NormalImpulse, const FHitResult& Hit)
{
	// Only add impulse and destroy projectile if we hit a physics
	if ((OtherActor != nullptr) && (OtherActor != this) && (OtherComp != nullptr) && OtherComp->IsSimulatingPhysics())
	{
		OtherComp->AddImpulseAtLocation(GetVelocity() * 100.0f, GetActorLocation());

		Destroy();
	}

	if (OtherActor != nullptr)
	{
		float frameNum = UKismetMathLibrary::RandomFloatInRange(0.f, 1.f);

		auto Decal = UGameplayStatics::SpawnDecalAtLocation(GetWorld(), baseMat, FVector(UKismetMathLibrary::RandomFloatInRange(20.f, 40.f)), Hit.Location, Hit.Normal.Rotation(), 0.f);
		auto MatInstance = Decal->CreateDynamicMaterialInstance();

		MatInstance->SetVectorParameterValue("Color", randColor);
		MatInstance->SetScalarParameterValue("Frame", frameNum);
	}
}

This is the screenshot of the projectile based off the C++ file

image
image1916×981 189 KB

I noticed another post similar to this one last year and tried to solve the issue by using any fixes mentioned in the forum post, but didn’t have any luck. Any help would be very appreciated. If you need any screenshots of other content in the project let me know.
Thanks.