有没有一种简单的方法来确定一个三角形内一个点？这是2D不是3D。

Is there an easy way to determine if a point inside a triangle? It's 2D not 3D.

推荐答案

在一般情况下，最简单的（和相当最佳）算法检查在其上的边缘点是

In general, the simplest (and quite optimal) algorithm is checking on which side of the half-plane created by the edges the point is.

下面是在GameDev 这话题，包括性能问题，一些高品质的信息。

Here's some high quality info in this topic on GameDev, including performance issues.

和这里的一些code，让你开始：

And here's some code to get you started:

float sign (fPoint p1, fPoint p2, fPoint p3)
{
    return (p1.x - p3.x) * (p2.y - p3.y) - (p2.x - p3.x) * (p1.y - p3.y);
}

bool PointInTriangle (fPoint pt, fPoint v1, fPoint v2, fPoint v3)
{
    bool b1, b2, b3;

    b1 = sign(pt, v1, v2) < 0.0f;
    b2 = sign(pt, v2, v3) < 0.0f;
    b3 = sign(pt, v3, v1) < 0.0f;

    return ((b1 == b2) && (b2 == b3));
}