做两线段相交于C＃或vb.net使用XNA？ [英] Do two line segments intersect in c# or vb.net using xna?

问题描述

我一直在寻找的年龄，如果发现两条线段（2套X，Y共同ords每个）拦截的一个合适的方法。我见过许多人（包括：<一href="http://stackoverflow.com/questions/563198/how-do-you-detect-where-two-line-segments-intersect">How你发现，其中两条线段相交？），但所有的一个我见过有瑕疵。主要是它们没有检测到碰撞，如果线是平行的，但彼此重叠。

I have been looking for ages for a suitable method of finding if two line segments (2 sets of x,y co-ords each) intercept. I have seen many (including: How do you detect where two line segments intersect?), but all the one I have seen have flaws. Mainly that they do not detect a collision if the lines are parallel but overlap each other.

我也不需要交点退换，只是一个布尔值就可以了。

I also do not need the point of intersection to be returned, just a boolean would be fine.

我会很感激，如果有人可以点我在正确的方向余弦显然我吸的几何形状。 ：（

I would be really grateful if someone could point me in the right direction cos apparently I suck at geometry. :(

推荐答案

当然，还有数学上优雅的方式来做到这一点，但如果你正在寻找一个易于理解的使用基本代数算法，试试这个（这不是code）：

There are certainly mathematically elegant ways to do it, but if you are looking for an easy-to-understand algorithm using basic algebra, try this (this is NOT code):

让我们通过自己的终端定义两个线段：

Let's define two line segments by their endpoints:

l0 : { (x0, y0), (x1, y1) }
l1 : { (x2, y2), {x3, y3) }

首先，获得每条线的斜率截距形式。你可以看一下公式M，B或自己获得他们：

First, obtain the slope-intercept form of each line. You can look up the formulae for m, b or derive them yourself:

l0 : m0 * x + b0
l1 : m1 * x + b1

如果（M0！= M1）的线不平行。要找到潜在的交叉点解决 10 = L1 ：

if (m0 != m1) the lines are not parallel. To find the potential intersection point solve l0 = l1:

x = (b1 - b0) / (m0 - m1)
y = m0 * x + b0

该段相交，当且仅当（X，Y）位于两个部分。请注意，这足以只检查的x坐标，因为我们已经建立了（X，Y）是两条线：

The segments will intersect if and only if (x, y) lies on both segments. Note that it is sufficient to check only the x-coordinate since we have already established that (x, y) is on both lines:

<打击>

(x0 <= x <= x1) AND (x2 <= x <= x3) AND (y0 <= y <= y1) AND (y2 <= y <= y3)

min(x0, x1) <= x <= max(x0, x1) AND min(x2, x3) <= x <= max(x2, x3)

如果线是平行的，你想知道他们是否重叠，替换一条线的端点对于x以上（您只需要在对面线测试，虽然）

If the lines are parallel and you want to know if they overlap, substitute the endpoints of one line for x above (you only need test against the opposite line, though)

希望这有助于。祝你好运！

Hope this helps. Good luck!

这篇关于做两线段相交于C＃或vb.net使用XNA？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！