C++ FPoly::Area方法代码示例

bool FKConvexElem::HullFromPlanes(const TArray<FPlane>& InPlanes, const TArray<FVector>& SnapVerts)
{
	// Start by clearing this convex.
	Reset();

	float TotalPolyArea = 0;

	for(int32 i=0; i<InPlanes.Num(); i++)
	{
		FPoly Polygon;
		Polygon.Normal = InPlanes[i];

		FVector AxisX, AxisY;
		Polygon.Normal.FindBestAxisVectors(AxisX,AxisY);

		const FVector Base = InPlanes[i] * InPlanes[i].W;

		new(Polygon.Vertices) FVector(Base + AxisX * HALF_WORLD_MAX + AxisY * HALF_WORLD_MAX);
		new(Polygon.Vertices) FVector(Base - AxisX * HALF_WORLD_MAX + AxisY * HALF_WORLD_MAX);
		new(Polygon.Vertices) FVector(Base - AxisX * HALF_WORLD_MAX - AxisY * HALF_WORLD_MAX);
		new(Polygon.Vertices) FVector(Base + AxisX * HALF_WORLD_MAX - AxisY * HALF_WORLD_MAX);

		for(int32 j=0; j<InPlanes.Num(); j++)
		{
			if(i != j)
			{
				if(!Polygon.Split(-FVector(InPlanes[j]), InPlanes[j] * InPlanes[j].W))
				{
					Polygon.Vertices.Empty();
					break;
				}
			}
		}

		// Do nothing if poly was completely clipped away.
		if(Polygon.Vertices.Num() > 0)
		{
			TotalPolyArea += Polygon.Area();

			// Add vertices of polygon to convex primitive.
			for(int32 j=0; j<Polygon.Vertices.Num(); j++)
			{
				// We try and snap the vert to on of the ones supplied.
				int32 NearestVert = INDEX_NONE;
				float NearestDistSqr = BIG_NUMBER;

				for(int32 k=0; k<SnapVerts.Num(); k++)
				{
					const float DistSquared = (Polygon.Vertices[j] - SnapVerts[k]).SizeSquared();

					if( DistSquared < NearestDistSqr )
					{
						NearestVert = k;
						NearestDistSqr = DistSquared;
					}
				}

				// If we have found a suitably close vertex, use that
				if( NearestVert != INDEX_NONE && NearestDistSqr < LOCAL_EPS )
				{
					const FVector localVert = SnapVerts[NearestVert];
					AddVertexIfNotPresent(VertexData, localVert);
				}
				else
				{
					const FVector localVert = Polygon.Vertices[j];
					AddVertexIfNotPresent(VertexData, localVert);
				}
			}
		}
	}

	// If the collision volume isn't closed, return an error so the model can be discarded
	if(TotalPolyArea < 0.001f)
	{
		UE_LOG(LogPhysics, Log,  TEXT("Total Polygon Area invalid: %f"), TotalPolyArea );
		return false;
	}

	// We need at least 4 vertices to make a convex hull with non-zero volume.
	// We shouldn't have the same vertex multiple times (using AddVertexIfNotPresent above)
	if(VertexData.Num() < 4)
	{
		return true;
	}

	// Check that not all vertices lie on a line (ie. find plane)
	// Again, this should be a non-zero vector because we shouldn't have duplicate verts.
	bool bFound = false;
	FVector Dir2, Dir1;

	Dir1 = VertexData[1] - VertexData[0];
	Dir1.Normalize();

	for(int32 i=2; i<VertexData.Num() && !bFound; i++)
	{
		Dir2 = VertexData[i] - VertexData[0];
		Dir2.Normalize();

		// If line are non-parallel, this vertex forms our plane
//.........这里部分代码省略.........