c++求两条直线的交点

一、已知每条直线的两个点：

cv::Point2d get2lineIPoint(cv::Point2d lineOnePt1, cv::Point2d lineOnePt2, cv::Point2d lineTwoPt1, cv::Point2d lineTwoPt2)
{
    
    
	double x;
	double y;

	cv::Point2d result(-1,-1);
	double k = (lineOnePt1.y - lineOnePt2.y) / (lineOnePt1.x- lineOnePt2.x);
	double b = lineOnePt1.y - k * lineOnePt1.x;

	double k1 = (lineTwoPt1.y - lineTwoPt2.y) / (lineTwoPt1.x - lineTwoPt2.x);
	double b1 = lineTwoPt1.y - k1 * lineTwoPt1.x;

	x = (b1 - b) / (k - k1);
	y = k * x + b;
	result.x = x;
	result.y = y;

	return result;
}

测试如下：

二、已知每条直线的一个点和方向(点斜式直线)

cv::Point2d get2lineIPoint(cv::Vec4f lineParam1, cv::Vec4f lineParam2)
{
    
    
	//Vec4f :参数的前半部分给出的是直线的方向，而后半部分给出的是直线上的一点
	cv::Point2d result(-1, -1);

	double cos_theta = lineParam1[0];
	double sin_theta = lineParam1[1];
	double x = lineParam1[2];
	double y = lineParam1[3];
	double k = sin_theta / cos_theta;
	double b = y - k * x;

	cos_theta = lineParam2[0];
	sin_theta = lineParam2[1];
	x = lineParam2[2];
    y = lineParam2[3];
	double k1 = sin_theta / cos_theta;
	double b1 = y - k1 * x;

	result.x = (b1 - b) / (k - k1);
	result.y = k * x + b;

	return result;
}