BallisticsDocs/Source/EasyBallistics/Private/EBBallisticImpactComponent.cpp

// Copyright 2016 Mookie. All Rights Reserved.

#include "EBBallisticImpactComponent.h"
#include "EBMathematicalBallistics.h"
#include "Engine/Engine.h"
#include "Kismet/KismetMathLibrary.h"

UEBBallisticImpactComponent::UEBBallisticImpactComponent()
{
	PrimaryComponentTick.bCanEverTick = false;
	bEnableBallisticCalculations = true;
	bUseMathematicalPenetration = false;
}

void UEBBallisticImpactComponent::BeginPlay()
{
	Super::BeginPlay();
}

FVector UEBBallisticImpactComponent::CalculateBallisticImpact(
	const FVector& ImpactLocation,
	const FVector& ProjectileVelocity,
	const FMathematicalBulletProperties& BulletProperties,
	UPhysicalMaterial* HitMaterial,
	float& OutPenetrationDepth,
	bool& bOutDidPenetrate,
	FVector& OutExitLocation)
{
	OutPenetrationDepth = 0.0f;
	bOutDidPenetrate = false;
	OutExitLocation = ImpactLocation;

	if (!bEnableBallisticCalculations || !HitMaterial)
	{
		return ImpactLocation;
	}

	// Get material response
	FEBMaterialResponseMapEntry MaterialResponse = GetMaterialResponse(HitMaterial);
	
	if (MaterialResponse.NeverPenetrate)
	{
		return ImpactLocation;
	}

	// Calculate penetration depth
	if (bUseMathematicalPenetration)
	{
		UEBMaterialPropertiesAsset* MaterialProps = GetMaterialProperties(HitMaterial);
		if (MaterialProps)
		{
			float VelocityMPS = ProjectileVelocity.Size() * 0.3048f; // feet to meters
			float ImpactAngle = CalculateImpactAngle(ProjectileVelocity, FVector::UpVector); // Simplified
			
			OutPenetrationDepth = UEBMathematicalBallistics::CalculatePenetrationDepth(
				BulletProperties,
				MaterialProps->MaterialProperties,
				VelocityMPS,
				ImpactAngle
			);
		}
	}
	else
	{
		// Use artistic approach
		float BaseDepth = ProjectileVelocity.Size() * 0.01f; // Simple velocity-based calculation
		OutPenetrationDepth = BaseDepth * MaterialResponse.PenetrationDepthMultiplier;
	}

	// Check if penetration occurred
	float MinPenetrationThreshold = 1.0f; // 1cm minimum
	bOutDidPenetrate = OutPenetrationDepth > MinPenetrationThreshold;

	if (bOutDidPenetrate)
	{
		// Calculate exit location
		FVector PenetrationDirection = ProjectileVelocity.GetSafeNormal();
		OutExitLocation = ImpactLocation + (PenetrationDirection * OutPenetrationDepth);
	}

	// Fire event
	OnBallisticImpact.Broadcast(ImpactLocation, FVector::UpVector, HitMaterial, OutPenetrationDepth, bOutDidPenetrate);

	return OutExitLocation;
}

FVector UEBBallisticImpactComponent::CalculateRicochet(
	const FVector& ImpactLocation,
	const FVector& ImpactNormal,
	const FVector& ProjectileVelocity,
	const FMathematicalBulletProperties& BulletProperties,
	UPhysicalMaterial* HitMaterial,
	float& OutEnergyRetained,
	bool& bOutDidRicochet)
{
	OutEnergyRetained = 0.0f;
	bOutDidRicochet = false;

	if (!bEnableBallisticCalculations || !HitMaterial)
	{
		return ProjectileVelocity;
	}

	// Get material response
	FEBMaterialResponseMapEntry MaterialResponse = GetMaterialResponse(HitMaterial);
	
	if (MaterialResponse.NeverRicochet)
	{
		return ProjectileVelocity;
	}

	// Calculate impact angle
	float ImpactAngle = CalculateImpactAngle(ProjectileVelocity, ImpactNormal);
	
	// Simple ricochet probability based on angle
	float RicochetProbability = FMath::Clamp((90.0f - ImpactAngle) / 90.0f, 0.0f, 1.0f);
	RicochetProbability *= MaterialResponse.RicochetProbabilityMultiplier;
	
	// Random chance for ricochet
	if (FMath::RandRange(0.0f, 1.0f) < RicochetProbability)
	{
		bOutDidRicochet = true;
		
		// Calculate ricochet direction using reflection
		FVector RicochetDirection = UKismetMathLibrary::GetReflectionVector(ProjectileVelocity, ImpactNormal);
		
		// Apply some randomness based on material response
		if (MaterialResponse.RicochetSpread > 0.0f)
		{
			FVector RandomOffset = FMath::VRand() * MaterialResponse.RicochetSpread;
			RicochetDirection = (RicochetDirection + RandomOffset).GetSafeNormal();
		}
		
		// Calculate energy retention
		OutEnergyRetained = MaterialResponse.RicochetRestitution;
		
		// Apply velocity reduction
		FVector NewVelocity = RicochetDirection * (ProjectileVelocity.Size() * OutEnergyRetained);
		
		// Fire event
		OnBallisticRicochet.Broadcast(ImpactLocation, RicochetDirection, HitMaterial, OutEnergyRetained);
		
		return NewVelocity;
	}

	return ProjectileVelocity;
}

UEBMaterialPropertiesAsset* UEBBallisticImpactComponent::GetMaterialProperties(UPhysicalMaterial* PhysicalMaterial)
{
	if (!PhysicalMaterial)
	{
		return nullptr;
	}

	// For now, use naming convention to find associated material properties
	// In production, you'd want a more robust system
	FString AssetName = PhysicalMaterial->GetName() + TEXT("_BallisticProps");
	FString PackageName = PhysicalMaterial->GetPackage()->GetName() + TEXT("_BallisticProps");
	
	return LoadObject<UEBMaterialPropertiesAsset>(nullptr, *PackageName, nullptr, LOAD_NoWarn | LOAD_Quiet);
}

FEBMaterialResponseMapEntry UEBBallisticImpactComponent::GetMaterialResponse(UPhysicalMaterial* PhysicalMaterial)
{
	FEBMaterialResponseMapEntry DefaultResponse;
	
	if (!MaterialResponseMap || !PhysicalMaterial)
	{
		return DefaultResponse;
	}

	if (FEBMaterialResponseMapEntry* Found = MaterialResponseMap->Map.Find(PhysicalMaterial))
	{
		return *Found;
	}

	return DefaultResponse;
}

FVector UEBBallisticImpactComponent::CalculatePenetrationVector(
	const FVector& ImpactLocation,
	const FVector& ImpactNormal,
	const FVector& ProjectileVelocity,
	float PenetrationDepth)
{
	FVector PenetrationDirection = ProjectileVelocity.GetSafeNormal();
	return ImpactLocation + (PenetrationDirection * PenetrationDepth);
}

float UEBBallisticImpactComponent::CalculateImpactAngle(const FVector& ProjectileVelocity, const FVector& SurfaceNormal)
{
	FVector NormalizedVelocity = ProjectileVelocity.GetSafeNormal();
	FVector NormalizedSurfaceNormal = SurfaceNormal.GetSafeNormal();
	
	float DotProduct = FVector::DotProduct(-NormalizedVelocity, NormalizedSurfaceNormal);
	float AngleRadians = FMath::Acos(FMath::Clamp(DotProduct, -1.0f, 1.0f));
	
	return FMath::RadiansToDegrees(AngleRadians);
}