UE4 C++ 记录UE4查找点距离直线最近的点_ue4 点到向量的距离

 1. 计算点距离线段上最近的点坐标

FVector FMath::ClosestPointOnLine(const FVector& LineStart, const FVector& LineEnd, const FVector& Point)
{
	// Solve to find alpha along line that is closest point
	// Weisstein, Eric W. "Point-Line Distance--3-Dimensional." From MathWorld--A Switchram Web Resource. http://mathworld.wolfram.com/Point-LineDistance3-Dimensional.html 
	const float A = (LineStart - Point) | (LineEnd - LineStart);
	const float B = (LineEnd - LineStart).SizeSquared();
	// This should be robust to B == 0 (resulting in NaN) because clamp should return 1.
	const float T = FMath::Clamp(-A/B, 0.f, 1.f);
 
	// Generate closest point
	FVector ClosestPoint = LineStart + (T * (LineEnd - LineStart));
 
	return ClosestPoint;
}

 2. 计算点距离直线上最近的点坐标

FVector FMath::ClosestPointOnInfiniteLine(const FVector& LineStart, const FVector& LineEnd, const FVector& Point)
{
	const float A = (LineStart - Point) | (LineEnd - LineStart);
	const float B = (LineEnd - LineStart).SizeSquared();
	if (B < SMALL_NUMBER)
	{
		return LineStart;
	}
	const float T = -A/B;
 
	// Generate closest point
	const FVector ClosestPoint = LineStart + (T * (LineEnd - LineStart));
	return ClosestPoint;
}

函数头文件  UE_4.27\Engine\Source\Runtime\Core\Public\Math\UnrealMath.h