c++ - 生成三角形边的代码

Question

我正在使用我发现的一些代码来测试两个三角形的交集。我遇到问题的代码部分是:

/*tr_tri_intersect3D - C1 is a vertex of triangle A. P1,P2 are the two edges originating from this vertex.
D1 is a vertex of triangle B. P1,P2 are the two edges originating from this vertex.
Returns zero for disjoint triangles and non-zero for intersection.*/

int tr_tri_intersect3D (double *C1, double *P1, double *P2,
double *D1, double *Q1, double *Q2);

我不明白的是，如果我有 2 个三角形的三个顶点，我需要做什么才能生成此函数的输入？

可以在以下位置找到完整的源代码:

Triangle Triangle Code

The source code had a test function, it was:

for (i = 0; i<10000; i++){
        for (j = 0; j<3; j++){
            for (k = 0; k<3; k++){
                PS[i][j][k] = drand48();
                QS[i][j][k] = drand48();
            }
        }
        for (j = 0; j<2; j++){
            for (k = 0; k<3; k++){
                EPS[i][j][k] = PS[i][j + 1][k] - PS[i][0][k];
                EQS[i][j][k] = QS[i][j + 1][k] - PS[i][0][k];
            }
        }
    }
    double sum = 0;
    int t0 = clock();
    int sums[100] = { 0 };
    for (j = 0; j<1000; j++)
        for (i = 0; i<10000; i++){
        int res = tr_tri_intersect3D(PS[i][0], EPS[i][0], EPS[i][1],
            QS[j][0], EQS[j][0], EQS[j][1]);
        sums[res]++;
        }

如果有帮助。

Answer 1

从示例代码看来，边的意思似乎是从起始顶点到结束顶点的 vector 。对于具有三个顶点 C1、C2、C3 的三角形，两个输入边将为 P1 = C2-C1，P2=C3-C1