From 8a7ee5faee6559c2e30e036073c7c6dd578abeee Mon Sep 17 00:00:00 2001
From: Louis Hobbs <bazzadobs@live.co.uk>
Date: Mon, 13 Mar 2023 22:58:21 +0000
Subject: [PATCH] Add basic logic to `EnemyCharacter` `OnFire` functions

---
 Source/Nakatomi/EnemyCharacter.cpp | 60 +++++++++++++++++++++++++++++-
 1 file changed, 59 insertions(+), 1 deletion(-)

diff --git a/Source/Nakatomi/EnemyCharacter.cpp b/Source/Nakatomi/EnemyCharacter.cpp
index 26b4fbf..ecdfadf 100644
--- a/Source/Nakatomi/EnemyCharacter.cpp
+++ b/Source/Nakatomi/EnemyCharacter.cpp
@@ -4,6 +4,8 @@
 #include "GameFramework/CharacterMovementComponent.h"
 #include "EnemyAIController.h"
 
+#define COLLISION_WEAPON	ECC_GameTraceChannel1
+
 AEnemyCharacter::AEnemyCharacter()
 {
 	PerceptionComponent = CreateDefaultSubobject<UAIPerceptionComponent>(TEXT("Perception Component"));
@@ -38,11 +40,17 @@ UAIPerceptionComponent* AEnemyCharacter::GetPerceptionComponent()
 
 void AEnemyCharacter::OnFire()
 {
+	CurrentWeapon->SetCurrentWeaponStatus(WeaponState::Firing);
+
 	TArray<FHitResult> Hits = TArray<FHitResult>();
 	CalculateHits(&Hits);
 	ProcessHits(Hits);
 
-	GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, TEXT("BANG"));
+	CurrentWeapon->PlayFireSoundAtLocation(GetActorLocation());
+
+	// TODO: Play some animation here
+
+	CurrentWeapon->SetCurrentWeaponStatus(WeaponState::Cooldown);
 }
 
 void AEnemyCharacter::BeginPlay()
@@ -52,8 +60,58 @@ void AEnemyCharacter::BeginPlay()
 
 void AEnemyCharacter::CalculateHits(TArray<FHitResult>* hits)
 {
+	// Set up randomness
+	const int32 RandomSeed = FMath::Rand();
+	FRandomStream WeaponRandomStream(RandomSeed);
+	const float Spread = CurrentWeapon->GetWeaponProperties()->WeaponSpread;
+	const float Range = CurrentWeapon->GetWeaponProperties()->ProjectileRange;
+
+	// Calculate starting position and direction
+	FVector TraceStart = this->GetTransform().GetLocation();
+	FRotator PlayerRot = this->GetTransform().GetRotation().Rotator();
+	TraceStart = GetRootComponent()->GetComponentLocation();
+	FVector AimDir = PlayerRot.Vector();
+	AimDir.Z = 0.0;
+	TraceStart = TraceStart + AimDir * ((GetInstigator()->GetActorLocation() - TraceStart) | AimDir);
+
+	// Calculate the hit results from the trace
+	TArray<FHitResult> HitResults;
+
+	// Set up the collision query params, use the Weapon trace settings, Ignore the actor firing this trace
+	FCollisionQueryParams TraceParams(SCENE_QUERY_STAT(WeaponTrace), true, GetInstigator());
+	TraceParams.bReturnPhysicalMaterial = true;
+
+	for (size_t i = 0; i < CurrentWeapon->GetWeaponProperties()->ProjectilesPerShot; i++)
+	{
+		// Calculate the maximum distance the weapon can fire
+		FVector ShootDir = WeaponRandomStream.VRandCone(AimDir, FMath::DegreesToRadians(Spread), FMath::DegreesToRadians(Spread));
+		FVector MaxHitLoc = TraceStart + (ShootDir * Range);
+
+		GetWorld()->LineTraceMultiByChannel(HitResults, TraceStart, MaxHitLoc, COLLISION_WEAPON, TraceParams);
+
+		for (FHitResult Result : HitResults)
+		{
+			hits->Add(Result);
+			DrawDebugLine(GetWorld(), TraceStart, Result.ImpactPoint, FColor::Red, true, 500, 0U, 0);
+		}
+	}
 }
 
 void AEnemyCharacter::ProcessHits(TArray<FHitResult> hits)
 {
+	for (FHitResult Hit : hits)
+	{
+		// TODO: Handle hits in a meaningful way
+		FActorSpawnParameters SpawnParameters;
+		SpawnParameters.SpawnCollisionHandlingOverride = ESpawnActorCollisionHandlingMethod::AlwaysSpawn;
+
+		// Spawn field actor
+		FTransform transform;
+		transform.SetLocation(Hit.ImpactPoint);
+		auto field = GetWorld()->SpawnActor<AFieldSystemActor>(CurrentWeapon->GetFieldSystemActor(), transform, SpawnParameters);
+
+		if (Hit.GetActor())
+		{
+		}
+	}
 }