[#9] [#53] Fire Off Gameplay Cue when Damage is Inflicted

This might get reworked later, since I am not sure if a GE exec is
supposed to make changes outside the scope of executing a GE, but this
seems like the best place to do this logic since it has all the context
about the type and amount of each damage type.

Config/Tags/PF2GameplayCues.ini

@@ -0,0 +1,8 @@
+; OpenPF2 for UE Game Logic, Copyright 2023, Guy Elsmore-Paddock. All Rights Reserved.
+;
+; This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0. If a copy of the MPL was not
+; distributed with this file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+; Gameplay Cues that provide special FX and sound FX in response to effect activations.
+[/Script/GameplayTags.GameplayTagsList]
+GameplayTagList=(Tag="GameplayCue.Character.InflictDamage", DevComment="Gameplay cue fired whenever one character inflicts damage on another.")

Source/OpenPF2Core/Private/Calculations/PF2ApplyDamageFromSourceExecution.cpp

@@ -17,6 +17,8 @@
 
 #include "Libraries/PF2AbilitySystemLibrary.h"
 
+#include "Utilities/PF2GameplayAbilityUtilities.h"
+
 UPF2ApplyDamageFromSourceExecution::UPF2ApplyDamageFromSourceExecution()
 {
 	const FPF2AttackAttributeStatics          AttackCaptures = FPF2AttackAttributeStatics::GetInstance();
@@ -28,15 +30,22 @@ UPF2ApplyDamageFromSourceExecution::UPF2ApplyDamageFromSourceExecution()
 	{
 		this->RelevantAttributesToCapture.Add(*Capture);
 	}
+
+	// Cache the tag to avoid lookup overhead.
+	this->InflictDamageCueTag = PF2GameplayAbilityUtilities::GetTag(
+		FName("GameplayCue.Character.InflictDamage")
+	);
 }
 
 void UPF2ApplyDamageFromSourceExecution::Execute_Implementation(
 	const FGameplayEffectCustomExecutionParameters& ExecutionParams,
 	FGameplayEffectCustomExecutionOutput&           OutExecutionOutput) const
 {
+	UAbilitySystemComponent*                  TargetAsc             = ExecutionParams.GetTargetAbilitySystemComponent();
 	const FPF2AttackAttributeStatics          AttackCaptures        = FPF2AttackAttributeStatics::GetInstance();
 	const FPF2TargetCharacterAttributeStatics TargetCaptures        = FPF2TargetCharacterAttributeStatics::GetInstance();
 	float                                     AttackDegreeOfSuccess = 0.0f;
+	bool                                      bHaveAnyDamage        = false;
 
 	const FAggregatorEvaluateParameters EvaluationParameters =
 		UPF2AbilitySystemLibrary::BuildEvaluationParameters(ExecutionParams);
@@ -102,6 +111,8 @@ void UPF2ApplyDamageFromSourceExecution::Execute_Implementation(
 
 		if (EffectiveDamage > 0)
 		{
+			FGameplayCueParameters CueParams = PopulateGameplayCueParameters(ExecutionParams);
+
 			// Apply: Damage, less resistance.
 			OutExecutionOutput.AddOutputModifier(
 				FGameplayModifierEvaluatedData(
@@ -110,6 +121,38 @@ void UPF2ApplyDamageFromSourceExecution::Execute_Implementation(
 					EffectiveDamage
 				)
 			);
+
+			bHaveAnyDamage = true;
+
+			// For now, pass the damage type along as a source tag. These feels like a hack, but saves us from having to
+			// define a custom parameter object and/or context object to pass along inside the parameter object.
+			//
+			// An alternative would be to pass the damage type along in the OriginalTag field, but the intent of that
+			// field appears to be to capture what gameplay tag was emitted by a GE to locate the cue. The
+			// MatchedTagName field, meanwhile, appears to be for holding the name of the tag that the selected cue has.
+			CueParams.AggregatedSourceTags.AddTag(
+				AttackCaptures.GetDamageTypeForDamageAttribute(Capture->AttributeToCapture)
+			);
+
+			CueParams.RawMagnitude = EffectiveDamage;
+
+			TargetAsc->ExecuteGameplayCue(
+				this->InflictDamageCueTag,
+				CueParams
+			);
 		}
 	}
+
+	if (!bHaveAnyDamage)
+	{
+		// Fire off a cue for a miss (no damage), so that the player can see a zero.
+		FGameplayCueParameters CueParams = PopulateGameplayCueParameters(ExecutionParams);
+
+		CueParams.RawMagnitude = 0;
+
+		TargetAsc->ExecuteGameplayCue(
+			this->InflictDamageCueTag,
+			CueParams
+		);
+	}
 }

Source/OpenPF2Core/Public/Calculations/PF2ApplyDamageFromSourceExecution.h

@@ -28,6 +28,11 @@ class OPENPF2CORE_API UPF2ApplyDamageFromSourceExecution : public UGameplayEffec
 {
 	GENERATED_BODY()
 
+	/**
+	 * The gameplay tag for gameplay cues that activate upon damage being inflicted to the target.
+	 */
+	FGameplayTag InflictDamageCueTag;
+
 public:
 	// =================================================================================================================
 	// Constructors
@@ -42,4 +47,32 @@ class OPENPF2CORE_API UPF2ApplyDamageFromSourceExecution : public UGameplayEffec
 	// =================================================================================================================
 	virtual void Execute_Implementation(const FGameplayEffectCustomExecutionParameters& ExecutionParams,
 	                                    OUT FGameplayEffectCustomExecutionOutput& OutExecutionOutput) const override;
+
+protected:
+	/**
+	 * Gets the gameplay tag for gameplay cues that activate upon damage being inflicted to the target.
+	 *
+	 * @return
+	 *	The gameplay tag for the damage cue.
+	 */
+	FORCEINLINE const FGameplayTag& GetInflictDamageCueTag() const
+	{
+		return this->InflictDamageCueTag;
+	}
+
+	/**
+	 * Populates parameters from a gameplay cue from the parameters of the current GE execution.
+	 *
+	 * @param [in] ExecutionParams
+	 *	The parameters passed to the current GE execution.
+	 *
+	 * @return
+	 *	The new Gameplay Cue parameters.
+	 */
+	FORCEINLINE FGameplayCueParameters PopulateGameplayCueParameters(
+		const FGameplayEffectCustomExecutionParameters& ExecutionParams) const
+	{
+		return FGameplayCueParameters(ExecutionParams.GetOwningSpec().GetEffectContext());
+	}
+
 };