Add aim assist

Config/DefaultEngine.ini

@@ -51,6 +51,7 @@ bUseSplitscreen=False
 +Profiles=(Name="UI",CollisionEnabled=QueryOnly,bCanModify=False,ObjectTypeName="WorldDynamic",CustomResponses=((Channel="WorldStatic",Response=ECR_Overlap),(Channel="Pawn",Response=ECR_Overlap),(Channel="Visibility"),(Channel="WorldDynamic",Response=ECR_Overlap),(Channel="Camera",Response=ECR_Overlap),(Channel="PhysicsBody",Response=ECR_Overlap),(Channel="Vehicle",Response=ECR_Overlap),(Channel="Destructible",Response=ECR_Overlap)),HelpMessage="WorldStatic object that overlaps all actors by default. All new custom channels will use its own default response. ")
 +Profiles=(Name="Pickup",CollisionEnabled=QueryAndPhysics,bCanModify=True,ObjectTypeName="WorldStatic",CustomResponses=((Channel="WorldStatic",Response=ECR_Overlap),(Channel="WorldDynamic",Response=ECR_Overlap),(Channel="Pawn",Response=ECR_Overlap),(Channel="Visibility",Response=ECR_Overlap),(Channel="Camera",Response=ECR_Overlap),(Channel="PhysicsBody",Response=ECR_Overlap),(Channel="Vehicle",Response=ECR_Overlap),(Channel="Destructible",Response=ECR_Overlap),(Channel="Character",Response=ECR_Overlap)),HelpMessage="Item to pickup")
 +DefaultChannelResponses=(Channel=ECC_GameTraceChannel1,DefaultResponse=ECR_Block,bTraceType=False,bStaticObject=False,Name="Character")
++DefaultChannelResponses=(Channel=ECC_GameTraceChannel2,DefaultResponse=ECR_Ignore,bTraceType=True,bStaticObject=False,Name="Enemy")
 -ProfileRedirects=(OldName="BlockingVolume",NewName="InvisibleWall")
 -ProfileRedirects=(OldName="InterpActor",NewName="IgnoreOnlyPawn")
 -ProfileRedirects=(OldName="StaticMeshComponent",NewName="BlockAllDynamic")

Source/PresidentsBrigade/BasePawn.cpp

@@ -4,9 +4,12 @@
 #include "BasePawn.h"
 #include "Components/StaticMeshComponent.h"
 #include "GameFramework/FloatingPawnMovement.h"
+#include "DrawDebugHelpers.h"
+#include "Kismet/KismetSystemLibrary.h"
 #include "Util.h"
 
 #define LogInfo(Msg) Util::log_info(TEXT("ABasePawn"), Msg)
+#define LogError(Msg) Util::log_error(TEXT("ABasePawn"), Msg)
 
 // Sets default values
 ABasePawn::ABasePawn(const FObjectInitializer &object_initializer): 
@@ -147,12 +150,30 @@ void ABasePawn::shoot()
 {
 	if (current_ammo > 0)
 	{
-		FVector player_location = player_mesh->GetComponentLocation();
-		const float y = yaw.calculate_yaw();
-		const FRotator rotator(0, y, 0);
-		FVector forward = FRotationMatrix(rotator).GetUnitAxis(EAxis::X) * 100;
+		const FVector player_location = get_location();
+		FRotator rotator(0, yaw.calculate_yaw(), 0);
+		if (use_aim_assist)
+		{
+			LogInfo(FString::Printf(TEXT("Yaw %f"), rotator.Yaw));
+			const float y_offset = aim_assist(player_location, rotator);
+			if (y_offset != 0)
+			{
+				rotator.Yaw = y_offset;
+			}
+			LogInfo(FString::Printf(TEXT("Offset %f"), y_offset));
+			FVector line_end = FVector(5000, 0, 0);
+			FVector aim_line_end = rotator.RotateVector(line_end);
+//			DrawDebugLine(
+//				GetWorld(),
+//				player_location, 
+//				aim_line_end + player_location,
+//				FColor::Red,
+//				true
+//			);
+		}
 
-		FVector spawn_location = player_location + forward;
+		FVector forward = FRotationMatrix(rotator).GetUnitAxis(EAxis::X);
+		FVector spawn_location = player_location + (forward * 100);
 		FActorSpawnParameters spawnParameters;
 		spawnParameters.SpawnCollisionHandlingOverride = ESpawnActorCollisionHandlingMethod::AlwaysSpawn;
 		spawnParameters.Owner = this;
@@ -169,6 +190,81 @@ void ABasePawn::shoot()
 	}
 }
 
+/**
+ * Calculate the yaw angle needed to hit the nearest enemy target.
+ * 
+ * @return Yaw angle offset.
+ */
+float ABasePawn::aim_assist(const FVector start, const FRotator rotator)
+{
+	/*
+	 * Create trace end based on start location and given rotator.
+	 */
+	FVector trace = start + FVector(10000, 0, 0);
+	trace = rotator.RotateVector(trace);
+
+	/*
+	 * Run box trace for enemy targets.
+	 */
+	FHitResult out_hit;
+	const bool succeeded = UKismetSystemLibrary::SphereTraceSingle(
+		GetWorld(),
+		start,
+		trace,
+		aim_assist_distance,
+		ETraceTypeQuery::TraceTypeQuery3, // "Enemy" trace channel
+		false,
+		TArray<AActor*>(),
+		EDrawDebugTrace::Type::None,
+		out_hit,
+		true,
+		FLinearColor::Green,
+		FLinearColor::Green,
+		0
+	);
+
+	/*
+	 * No enemies were within range.
+	 */
+	if (!succeeded)
+	{
+		return 0;
+	}
+
+	ABasePawn* enemy_pawn = Cast<ABasePawn>(out_hit.Actor);
+	/*
+	 * Bad setup. We should only be hitting pawns.
+	 */
+	if (!enemy_pawn)
+	{
+		LogError("Aim assist trace hit non-pawn");
+		return 0;
+	}
+
+	const FVector enemy_vector = enemy_pawn->get_location() - start;
+	const FRotator new_rotator = enemy_vector.Rotation();
+
+	//FVector target_vector = FVector(enemy_vector.X, enemy_vector.Y, 0);
+	//target_vector.Normalize();
+
+	//FVector actual_vector = FVector(trace.X, trace.Y, 0) - start;
+	//actual_vector.Normalize();
+
+	//const float angle_between = UKismetMathLibrary::DegAcos(FVector::DotProduct(actual_vector, target_vector));
+	//const FVector cross = FVector::CrossProduct(actual_vector, target_vector);
+	//if (cross.Z > 0)
+	//{
+	//	return angle_between;
+	//}
+	//else if (cross.Z < 0)
+	//{
+	//	return angle_between * -1;
+	//}
+
+	//return 0;
+	return new_rotator.Yaw;
+}
+
 void ABasePawn::handle_death()
 {
 	/*

Source/PresidentsBrigade/BasePawn.h

@@ -112,11 +112,20 @@ protected:
 	float fire_rate_s;
 
 	/**
-	 * Max ammor.
+	 * Max ammo.
 	 */
 	UPROPERTY(EditAnywhere, Category = "Attack")
 	int32 max_ammo;
 
+	/**
+	 *
+	 */
+	UPROPERTY(EditAnywhere, Category = "Attack")
+	float aim_assist_distance;
+
+	UPROPERTY(EditAnywhere, Category = "Attack")
+	bool use_aim_assist;
+
 	/**
 	 * Shooting enabled;
 	 */
@@ -146,4 +155,7 @@ protected:
 	 * Spawned death effect actor.
 	 */
 	AActor* death_effect;
+
+private:
+	float aim_assist(const FVector start, const FRotator rotator);
 };

Source/PresidentsBrigade/EnemyAIController.cpp

@@ -38,14 +38,24 @@ void AEnemyAIController::Tick(float delta_time)
 		else
 		{
 			FVector target_location = president->get_location();
-			FVector current_location = Cast<ABasePawn>(GetPawn())->get_location();
-			FVector between = target_location - current_location;
-			between = FVector(between.X, between.Y, 0);
-			between.Normalize();
-			FVector extended = (between * overshoot_multiplier) + target_location;
+			const ABasePawn* local_pawn = Cast<ABasePawn>(GetPawn());
+			if (local_pawn)
+			{
+				FVector current_location = local_pawn->get_location();
+				FVector between = target_location - current_location;
+				between = FVector(between.X, between.Y, 0);
+				between.Normalize();
+				FVector extended = (between * overshoot_multiplier) + target_location;
+
+				MoveToLocation(extended);
+				current_state = state_t::moving;
+			}
+			else
+			{
+				// This will be cleaned up shortly.
+				current_state = state_t::dead;
+			}
 
-			MoveToLocation(extended);
-			current_state = state_t::moving;
 		}
 		break;
 	case state_t::moving:
@@ -95,7 +105,7 @@ ABasePawn* AEnemyAIController::get_president() const
 
 	if (!found)
 	{
-		LogError("No president found!");
+	//	LogError("No president found!");
 	}
 
 	return found;

Source/PresidentsBrigade/EnemyAIController.h

@@ -43,6 +43,7 @@ private:
 		wait,
 		target,
 		moving,
+		dead
 	};
 
 	ABasePawn* get_president() const;

todo.txt

@@ -14,6 +14,10 @@ xShoot from any direction
 xShoot at continuous rate when holding shoot button
 xAdd player damage
 xAdd player ammo
+xAdd auto aim
+Add art
+  - Car models
+  - Street shader
 Add win condition
   - Time based. Keep president alive until he reaches destination.
 Add HUD UI
@@ -21,9 +25,6 @@ Add menu
 Add local multiplayer
   x Blueprint
   - C++
-Add art
-  - Car models
-  - Street shader
 Add sounds
 Add juice
   Add muzzle on shoot