分离轴算法判断两凸多边形是否相交

//两多边形是否相交
public static bool IsPolygonIntersect(Vector2[] polygon1, Vector2[] polygon2)
{
    //多边形1的所有边的法向量作为分离轴
    int edgeCount1 = polygon1.Length;
    for (int i = 0; i < edgeCount1; ++i)
    {
        var edge = polygon1[(i + 1) % edgeCount1] - polygon1[i];
        var sepAxis = new Vector2(-edge.y, edge.x); //将边的法向量(左)作为分离轴
        ProjOnSeparatingAxis(polygon1, sepAxis, out var minA, out var maxA);
        ProjOnSeparatingAxis(polygon2, sepAxis, out var minB, out var maxB);
        if (!IsProjIntersect(minA, maxA, minB, maxB))
            return false;
    }

    //多边形2的所有边的法向量作为分离轴
    int edgeCount2 = polygon2.Length;
    for (int i = 0; i < edgeCount2; ++i)
    {
        var edge = polygon2[(i + 1) % edgeCount2] - polygon2[i];
        var sepAxis = new Vector2(-edge.y, edge.x); //将边的法向量(左)作为分离轴
        ProjOnSeparatingAxis(polygon1, sepAxis, out var minA, out var maxA);
        ProjOnSeparatingAxis(polygon2, sepAxis, out var minB, out var maxB);
        if (!IsProjIntersect(minA, maxA, minB, maxB))
            return false;
    }

    return true;
}

//多边形的所有点在分离轴上投影, 找出最小和最大投影距离
public static void ProjOnSeparatingAxis(Vector2[] polygon, Vector2 sepAxis, out float min, out float max)
{
    min = float.MaxValue;
    max = float.MinValue;
    for (int i = 0; i < polygon.Length; ++i)
    {
        var vert = polygon[i];
        float dot = Vector2.Dot(sepAxis, vert);
        min = Mathf.Min(min, dot);
        max = Mathf.Max(max, dot);
    }
}

//在分离轴的投影是否相交
public static bool IsProjIntersect(float minA, float maxA, float minB, float maxB)
{
    if (minA < minB)
        return maxA > minB;
    return maxB > minA;
}