UE4 ShooterGame Demo的开火的代码

之前一直没搞懂按下鼠标左键开火之后，代码的逻辑是怎么走的，今天看懂了之前没看懂的部分，进了一步

ShooterCharacter.cpp

void AShooterCharacter::OnStartFire()
{AShooterPlayerController* MyPC = Cast<AShooterPlayerController>(Controller);if (MyPC && MyPC->IsGameInputAllowed()){if (IsRunning()){SetRunning(false, false);}StartWeaponFire();}
}

void AShooterCharacter::StartWeaponFire()
{if (!bWantsToFire){bWantsToFire = true;if (CurrentWeapon){CurrentWeapon->StartFire();}}
}

ShooterWeapon.cpp，其中Role==ROLE_Authority表示该程序运行在服务器。如果是客户端，则将调用ServerStartFire来调用服务端的StartFire方法。这是多人游戏中的机制

void AShooterWeapon::StartFire()
{if (Role < ROLE_Authority){ServerStartFire();}if (!bWantsToFire){bWantsToFire = true;DetermineWeaponState();}
}

 

void AShooterWeapon::DetermineWeaponState()
{EWeaponState::Type NewState = EWeaponState::Idle;if (bIsEquipped){if( bPendingReload  ){if( CanReload() == false ){NewState = CurrentState;}else{NewState = EWeaponState::Reloading;}}        else if ( (bPendingReload == false ) && ( bWantsToFire == true ) && ( CanFire() == true )){NewState = EWeaponState::Firing;}}else if (bPendingEquip){NewState = EWeaponState::Equipping;}SetWeaponState(NewState);
}

 

void AShooterWeapon::SetWeaponState(EWeaponState::Type NewState)
{const EWeaponState::Type PrevState = CurrentState;if (PrevState == EWeaponState::Firing && NewState != EWeaponState::Firing){OnBurstFinished();}CurrentState = NewState;if (PrevState != EWeaponState::Firing && NewState == EWeaponState::Firing){OnBurstStarted();}
}

 

void AShooterWeapon::OnBurstStarted()
{// start firing, can be delayed to satisfy TimeBetweenShotsconst float GameTime = GetWorld()->GetTimeSeconds();if (LastFireTime > 0 && WeaponConfig.TimeBetweenShots > 0.0f &&LastFireTime + WeaponConfig.TimeBetweenShots > GameTime){GetWorldTimerManager().SetTimer(TimerHandle_HandleFiring, this, &AShooterWeapon::HandleFiring, LastFireTime + WeaponConfig.TimeBetweenShots - GameTime, false);}else{HandleFiring();}
}

下面标红的FireWeapon这个函数，实际上在AShooterWeapon中是一个虚函数，并且没有实现，实现是放在了子类中。它有两个子类，分别是AShooterWeapon_Instant（弹道类）和AShooterWeapon_Projectile（投掷类）

我觉得肯定真正使用到的类就是这两个子类，所以包括之前的这个流程，实际上都是子类中的，只不过是从父类中继承而已，当然我此时此刻没有去深究那些方法的可见性修饰符，是否会被继承这些细节问题，我先暂时这么认为吧

void AShooterWeapon::HandleFiring()
{if ((CurrentAmmoInClip > 0 || HasInfiniteClip() || HasInfiniteAmmo()) && CanFire()){if (GetNetMode() != NM_DedicatedServer){SimulateWeaponFire();}if (MyPawn && MyPawn->IsLocallyControlled()){FireWeapon();UseAmmo();// update firing FX on remote clients if function was called on serverBurstCounter++;}}else if (CanReload()){StartReload();}else if (MyPawn && MyPawn->IsLocallyControlled()){if (GetCurrentAmmo() == 0 && !bRefiring){PlayWeaponSound(OutOfAmmoSound);AShooterPlayerController* MyPC = Cast<AShooterPlayerController>(MyPawn->Controller);AShooterHUD* MyHUD = MyPC ? Cast<AShooterHUD>(MyPC->GetHUD()) : NULL;if (MyHUD){MyHUD->NotifyOutOfAmmo();}}// stop weapon fire FX, but stay in Firing stateif (BurstCounter > 0){OnBurstFinished();}}if (MyPawn && MyPawn->IsLocallyControlled()){// local client will notify serverif (Role < ROLE_Authority){ServerHandleFiring();}// reload after firing last roundif (CurrentAmmoInClip <= 0 && CanReload()){StartReload();}// setup refire timerbRefiring = (CurrentState == EWeaponState::Firing && WeaponConfig.TimeBetweenShots > 0.0f);if (bRefiring){GetWorldTimerManager().SetTimer(TimerHandle_HandleFiring, this, &AShooterWeapon::HandleFiring, WeaponConfig.TimeBetweenShots, false);}}LastFireTime = GetWorld()->GetTimeSeconds();
}

 

void AShooterWeapon_Instant::FireWeapon()
{const int32 RandomSeed = FMath::Rand();FRandomStream WeaponRandomStream(RandomSeed);const float CurrentSpread = GetCurrentSpread();const float ConeHalfAngle = FMath::DegreesToRadians(CurrentSpread * 0.5f);

　　 //获取AShooterPlayerController的rotation的单位向量const FVector AimDir = GetAdjustedAim();const FVector StartTrace = GetCameraDamageStartLocation(AimDir);const FVector ShootDir = WeaponRandomStream.VRandCone(AimDir, ConeHalfAngle, ConeHalfAngle);const FVector EndTrace = StartTrace + ShootDir * InstantConfig.WeaponRange;const FHitResult Impact = WeaponTrace(StartTrace, EndTrace);ProcessInstantHit(Impact, StartTrace, ShootDir, RandomSeed, CurrentSpread);CurrentFiringSpread = FMath::Min(InstantConfig.FiringSpreadMax, CurrentFiringSpread + InstantConfig.FiringSpreadIncrement);
}