c++ - 返回值 1.#INF000

Question

交集算法不起作用；其中一个值 tmin 的计算结果为 1.#INF000 - 这是什么意思，为什么会这样？ tmax 似乎没问题。

float Ray::Intersects(BoundingBox boundingBox)
{
// direction is unit direction vector of the ray
D3DXVECTOR3 dirfrac(
    1.0f / direction.x,
    1.0f / direction.y,
    1.0f / direction.z);

D3DXVECTOR3 min = boundingBox.Min();
D3DXVECTOR3 max = boundingBox.Max();

//min and max are the negative and positive corners of the bounding box
float t1 = (min.x - origin.x) * dirfrac.x;
float t2 = (max.x - origin.x) * dirfrac.x;
float t3 = (min.y - origin.y) * dirfrac.y;
float t4 = (max.y - origin.y) * dirfrac.y;
float t5 = (min.z - origin.z) * dirfrac.z;
float t6 = (max.z - origin.z) * dirfrac.z;

float tmin = max(max(min(t1, t2), min(t3, t4)), min(t5, t6));
float tmax = min(min(max(t1, t2), max(t3, t4)), max(t5, t6));

// if tmax < 0, ray (line) is intersecting AABB, but whole AABB is behind us
if (tmax < 0) { return -1; }

// if tmin > tmax, ray doesn't intersect AABB
if (tmin > tmax) { return -1; } //HERE TMIN IS 1.#INFOOO

return tmin; //THIS IS NEVER REACHED
}

Answer 1

1.#INF000 很可能是正无穷大。如果你得到这个，这意味着你的代码出现以下情况之一:

• t1 和t2 都是无限的
• t3 和t4 都是无限的
• t5 和t6 都是无限的

我的猜测是您可能在某处除以零，最有可能是在计算 dirfrac 的值时。