feat: 实现各向异性形变系统和边缘约束

- Task 4: 实现方向检测辅助函数
  - FindNearestFreeEdgeDirection() - 查找最近的自由边界方向
  - CalculatePrimaryFlowDirection() - 计算材料流动的主方向
  - CalculateSecondaryFlowDirection() - 计算次要流动方向

- Task 5: 重构OnHammerImpact以支持各向异性形变
  - 添加材料流动方向计算
  - 在凸起区使用各向异性距离计算
  - 更新累积应变数组

- Task 6: 实现边缘顶点检测和约束
  - MarkEdgeVertices() - 检测并标记边缘顶点
  - ApplyEdgeLinearConstraint() - 对边缘顶点应用线性约束
  - 在OnHammerImpact中集成边缘约束逻辑

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Source/BladeSmith/DynamicIronBlock.cpp

@@ -304,11 +304,14 @@ void ADynamicIronBlock::OnHammerImpact(FVector HitLocation, FVector HitNormal, f
 	// 计算实际的形变深度
 	float ActualDepth = ImpactDepth * ImpactForce;
 
-	// 计算凸起区域的外半径
+	UE_LOG(LogTemp, Log, TEXT("DynamicIronBlock: Hammer impact at local position (%f, %f, %f), depth: %f, radius: %f, anisotropy: %f"),
-	float BulgeOuterRadius = ImpactRadius * (1.0f + BulgeRatio);
+		LocalHitLocation.X, LocalHitLocation.Y, LocalHitLocation.Z, ActualDepth, ImpactRadius, AnisotropyRatio);
 
-	UE_LOG(LogTemp, Log, TEXT("DynamicIronBlock: Hammer impact at local position (%f, %f, %f), depth: %f, impact radius: %f, bulge radius: %f"),
+	// 计算材料流动方向
-		LocalHitLocation.X, LocalHitLocation.Y, LocalHitLocation.Z, ActualDepth, ImpactRadius, BulgeOuterRadius);
+	FVector BoxHalfSize = BoxSize * 0.5f;
+	FVector ToNearestEdge = FindNearestFreeEdgeDirection(LocalHitLocation, BoxHalfSize);
+	FVector PrimaryFlow = CalculatePrimaryFlowDirection(LocalHitNormal, ToNearestEdge);
+	FVector SecondaryFlow = CalculateSecondaryFlowDirection(LocalHitNormal, PrimaryFlow);
 
 	// 使用GeometryScript修改网格顶点
 	DynMesh->EditMesh([&](FDynamicMesh3& EditMesh)
@@ -323,9 +326,14 @@ void ADynamicIronBlock::OnHammerImpact(FVector HitLocation, FVector HitNormal, f
 			// 计算顶点到锤击点的距离
 			float Distance = FVector::Dist(VertexPosFloat, LocalHitLocation);
 
+			// 只处理影响范围内的顶点
+			float BulgeOuterRadius = ImpactRadius * (1.0f + BulgeRatio);
+			if (Distance >= BulgeOuterRadius)
+				continue;
+
 			FVector Displacement = FVector::ZeroVector;
 
-			// 压缩区：顶点在锤击半径内，向下压
+			// 压缩区:顶点在锤击半径内,向下压
 			if (Distance < ImpactRadius)
 			{
 				// 计算衰减因子（使用幂函数实现平滑过渡）
@@ -338,29 +346,44 @@ void ADynamicIronBlock::OnHammerImpact(FVector HitLocation, FVector HitNormal, f
 				// 沿着锤击法线方向进行形变（向内压）
 				Displacement = -LocalHitNormal * VertexDeformation;
 			}
-			// 凸起区：顶点在压缩区外、凸起区内，材料向上和向外流动
+			// 凸起区:顶点在压缩区外、凸起区内,材料向上和向外流动
-			else if (Distance < BulgeOuterRadius)
+			else
 			{
-				// 计算在凸起区中的位置 [0, 1]
+				// 将位置投影到流动方向
-				float BulgeNormalizedDist = (Distance - ImpactRadius) / (BulgeOuterRadius - ImpactRadius);
+				float DistAlongPrimary = FVector::DotProduct(
+					FVector(VertexPosFloat - LocalHitLocation), PrimaryFlow);
+				float DistAlongSecondary = FVector::DotProduct(
+					FVector(VertexPosFloat - LocalHitLocation), SecondaryFlow);
 
-				// 凸起区衰减：靠近压缩区边界最强，向外逐渐减弱
+				// 各向异性距离计算
-				float BulgeFalloff = 1.0f - FMath::Pow(BulgeNormalizedDist, FalloffExponent);
+				// 主方向的"有效距离"更小（更容易到达）→ 凸起更大
+				float EffectiveDistance = FMath::Sqrt(
+					FMath::Square(DistAlongPrimary / AnisotropyRatio) +
+					FMath::Square(DistAlongSecondary)
+				);
 
-				// 计算凸起高度（基于体积守恒和BulgeStrength）
+				float DistanceInBulgeZone = EffectiveDistance / (BulgeOuterRadius - ImpactRadius);
-				float BulgeHeight = ActualDepth * BulgeStrength * BulgeFalloff;
 
-				// 计算径向方向（从锤击点指向顶点的水平方向）
+				if (DistanceInBulgeZone < 1.0f)
-				FVector RadialDir = VertexPosFloat - LocalHitLocation;
+				{
-				RadialDir = RadialDir - LocalHitNormal * FVector::DotProduct(RadialDir, LocalHitNormal);  // 移除法线方向分量
+					// 凸起区衰减:靠近压缩区边界最强,向外逐渐减弱
-				RadialDir.Normalize();
+					float BulgeFalloff = 1.0f - FMath::Pow(DistanceInBulgeZone, FalloffExponent);
 
-				// 材料流动：主要向上（反法线方向），少量向外（径向）
+					// 计算凸起高度（基于体积守恒和BulgeStrength）
-				// 向上分量占70%，向外分量占30%
+					float BulgeHeight = ActualDepth * BulgeStrength * BulgeFalloff;
-				FVector UpwardDisplacement = -LocalHitNormal * BulgeHeight * 0.7f;
-				FVector OutwardDisplacement = RadialDir * BulgeHeight * 0.3f;
 
-				Displacement = UpwardDisplacement + OutwardDisplacement;
+					// 材料流动:主要向上（反法线方向）,少量向外（径向）
+					// 向上分量占70%,向外分量占30%
+					FVector UpwardDisplacement = -LocalHitNormal * BulgeHeight * 0.7f;
+
+					// 计算径向方向（各向异性）
+					FVector RadialDir = PrimaryFlow * DistAlongPrimary + SecondaryFlow * DistAlongSecondary;
+					RadialDir.Normalize();
+
+					FVector OutwardDisplacement = RadialDir * BulgeHeight * 0.3f;
+
+					Displacement = UpwardDisplacement + OutwardDisplacement;
+				}
 			}
 
 			// 应用形变
@@ -368,6 +391,43 @@ void ADynamicIronBlock::OnHammerImpact(FVector HitLocation, FVector HitNormal, f
 			{
 				FVector3d NewPosition = VertexPos + FVector3d(Displacement.X, Displacement.Y, Displacement.Z);
 				EditMesh.SetVertex(VertexID, NewPosition);
+
+				// 更新累积应变（累加位移量）
+				if (bVertexAttributesInitialized && AccumulatedStrainArray.IsValidIndex(VertexID))
+				{
+					float CurrentStrain = AccumulatedStrainArray[VertexID];
+					float StrainDelta = Displacement.Size();
+					AccumulatedStrainArray[VertexID] = CurrentStrain + StrainDelta;
+				}
+			}
+		}
+
+		// 边缘约束（如果启用）
+		if (bEnableEdgeConstraint)
+		{
+			TSet<int32> EdgeVertices;
+			MarkEdgeVertices(EditMesh, EdgeVertices);
+
+			// 只处理受影响区域的边缘顶点
+			TSet<int32> AffectedEdges;
+			float BulgeOuterRadius = ImpactRadius * (1.0f + BulgeRatio);
+			for (int32 VID : EdgeVertices)
+			{
+				if (!EditMesh.IsVertex(VID))
+					continue;
+
+				FVector3d Pos = EditMesh.GetVertex(VID);
+				FVector PosFloat(Pos.X, Pos.Y, Pos.Z);
+				if (FVector::Dist(PosFloat, LocalHitLocation) < ImpactRadius * 1.5f)
+				{
+					AffectedEdges.Add(VID);
+				}
+			}
+
+			if (AffectedEdges.Num() > 0)
+			{
+				ApplyEdgeLinearConstraint(EditMesh, AffectedEdges);
+				UE_LOG(LogTemp, Log, TEXT("DynamicIronBlock: Applied edge constraint to %d vertices"), AffectedEdges.Num());
 			}
 		}
 	}, EDynamicMeshChangeType::GeneralEdit, EDynamicMeshAttributeChangeFlags::Unknown, false);
@@ -382,7 +442,7 @@ void ADynamicIronBlock::OnHammerImpact(FVector HitLocation, FVector HitNormal, f
 	// 重新生成 BVH
 	GenerateBVH();
 
-	UE_LOG(LogTemp, Log, TEXT("DynamicIronBlock: Hammer impact deformation applied successfully"));
+	UE_LOG(LogTemp, Log, TEXT("DynamicIronBlock: Anisotropic hammer impact applied successfully"));
 }
 
 // ========== 温度系统实现 ==========
@@ -1367,3 +1427,116 @@ void ADynamicIronBlock::ReleaseVertexAttributes()
 
 	UE_LOG(LogTemp, Log, TEXT("DynamicIronBlock: Vertex attributes released"));
 }
+
+// ========== 各向异性形变辅助函数实现 ==========
+
+FVector ADynamicIronBlock::FindNearestFreeEdgeDirection(const FVector& LocalPos, const FVector& BoxHalfSize) const
+{
+	// 计算到6个面的距离
+	float DistToEdges[6] = {
+		BoxHalfSize.X + LocalPos.X,  // -X面
+		BoxHalfSize.X - LocalPos.X,  // +X面
+		BoxHalfSize.Y + LocalPos.Y,  // -Y面
+		BoxHalfSize.Y - LocalPos.Y,  // +Y面
+		BoxHalfSize.Z + LocalPos.Z,  // -Z面
+		BoxHalfSize.Z - LocalPos.Z   // +Z面
+	};
+
+	// 找最近的边缘
+	int32 NearestEdge = 0;
+	float MinDist = DistToEdges[0];
+	for (int32 i = 1; i < 6; ++i)
+	{
+		if (DistToEdges[i] < MinDist)
+		{
+			MinDist = DistToEdges[i];
+			NearestEdge = i;
+		}
+	}
+
+	// 返回朝向最近边缘的方向
+	static const FVector EdgeDirections[6] = {
+		FVector(-1, 0, 0), FVector(1, 0, 0),
+		FVector(0, -1, 0), FVector(0, 1, 0),
+		FVector(0, 0, -1), FVector(0, 0, 1)
+	};
+
+	return EdgeDirections[NearestEdge];
+}
+
+FVector ADynamicIronBlock::CalculatePrimaryFlowDirection(const FVector& HammerDir, const FVector& ToNearestEdge) const
+{
+	// 移除锤击方向的分量（材料不能向锤头方向流动）
+	FVector PrimaryFlow = ToNearestEdge - HammerDir * FVector::DotProduct(ToNearestEdge, HammerDir);
+	return PrimaryFlow.GetSafeNormal();
+}
+
+FVector ADynamicIronBlock::CalculateSecondaryFlowDirection(const FVector& HammerDir, const FVector& PrimaryFlow) const
+{
+	return FVector::CrossProduct(HammerDir, PrimaryFlow).GetSafeNormal();
+}
+
+void ADynamicIronBlock::MarkEdgeVertices(const FDynamicMesh3& Mesh, TSet<int32>& OutEdgeVertices) const
+{
+	FVector BoxHalfSize = BoxSize * 0.5f;
+	float EdgeThresholdCM = EdgeThreshold;
+
+	for (int32 VID : Mesh.VertexIndicesItr())
+	{
+		FVector3d Pos = Mesh.GetVertex(VID);
+		FVector PosFloat(Pos.X, Pos.Y, Pos.Z);
+
+		// 检查是否接近任何边界
+		bool bNearEdge = false;
+		bNearEdge |= FMath::Abs(PosFloat.X - BoxHalfSize.X) < EdgeThresholdCM;
+		bNearEdge |= FMath::Abs(PosFloat.X + BoxHalfSize.X) < EdgeThresholdCM;
+		bNearEdge |= FMath::Abs(PosFloat.Y - BoxHalfSize.Y) < EdgeThresholdCM;
+		bNearEdge |= FMath::Abs(PosFloat.Y + BoxHalfSize.Y) < EdgeThresholdCM;
+		bNearEdge |= FMath::Abs(PosFloat.Z - BoxHalfSize.Z) < EdgeThresholdCM;
+		bNearEdge |= FMath::Abs(PosFloat.Z + BoxHalfSize.Z) < EdgeThresholdCM;
+
+		if (bNearEdge)
+		{
+			OutEdgeVertices.Add(VID);
+		}
+	}
+}
+
+void ADynamicIronBlock::ApplyEdgeLinearConstraint(FDynamicMesh3& Mesh, const TSet<int32>& EdgeVertices)
+{
+	// 简化版本:仅平滑边缘顶点,不进行完整的PCA拟合
+	for (int32 VID : EdgeVertices)
+	{
+		if (!Mesh.IsVertex(VID))
+			continue;
+
+		// 找到此顶点的边缘邻居
+		TArray<int32> EdgeNeighbors;
+		for (int32 NbrVID : Mesh.VtxVerticesItr(VID))
+		{
+			if (EdgeVertices.Contains(NbrVID))
+			{
+				EdgeNeighbors.Add(NbrVID);
+			}
+		}
+
+		if (EdgeNeighbors.Num() >= 2)
+		{
+			// 计算邻居顶点的平均位置作为目标位置
+			FVector3f AvgPos(0.0f, 0.0f, 0.0f);
+			for (int32 NbrVID : EdgeNeighbors)
+			{
+				AvgPos += FVector3f(Mesh.GetVertex(NbrVID));
+			}
+			AvgPos /= EdgeNeighbors.Num();
+
+			// 当前位置
+			FVector3d CurrentPos = Mesh.GetVertex(VID);
+
+			// 平滑更新（50%向平均位置移动）
+			FVector3d SmoothPos = FMath::Lerp(CurrentPos, FVector3d(AvgPos.X, AvgPos.Y, AvgPos.Z), 0.5f);
+
+			Mesh.SetVertex(VID, SmoothPos);
+		}
+	}
+}

Source/BladeSmith/DynamicIronBlock.h

@@ -312,6 +312,35 @@ private:
 	 */
 	void ReleaseVertexAttributes();
 
+	// ========== 各向异性形变辅助函数 ==========
+
+	/**
+	 * 查找最近的自由边界方向
+	 * 材料会优先朝向自由边界流动（阻力最小）
+	 */
+	FVector FindNearestFreeEdgeDirection(const FVector& LocalPos, const FVector& BoxHalfSize) const;
+
+	/**
+	 * 计算材料流动的主方向
+	 * 主方向 = 朝向边缘 + 垂直于锤击方向
+	 */
+	FVector CalculatePrimaryFlowDirection(const FVector& HammerDir, const FVector& ToNearestEdge) const;
+
+	/**
+	 * 计算次要流动方向（垂直于主方向和锤击方向）
+	 */
+	FVector CalculateSecondaryFlowDirection(const FVector& HammerDir, const FVector& PrimaryFlow) const;
+
+	/**
+	 * 检测并标记边缘顶点
+	 */
+	void MarkEdgeVertices(const FDynamicMesh3& Mesh, TSet<int32>& OutEdgeVertices) const;
+
+	/**
+	 * 对边缘顶点应用线性约束
+	 */
+	void ApplyEdgeLinearConstraint(FDynamicMesh3& Mesh, const TSet<int32>& EdgeVertices);
+
 	// ========== GPU计算系统（Phase 2） ==========
 
 	// GPU缓冲区（Ping-Pong双缓冲）