射线平面相交怎么办？ [英] How to do ray plane intersection?

问题描述

我如何计算射线与平面之间的交点？

How do I calculate the intersection between a ray and a plane?

这会产生错误的结果。

float denom = normal.dot(ray.direction);

if (denom > 0)
{
    float t = -((center - ray.origin).dot(normal)) / denom;

    if (t >= 0)
    {
        rec.tHit = t;
        rec.anyHit = true;
        computeSurfaceHitFields(ray, rec);
        return true;
    }
}

参数

ray 表示射线对象。

ray.direction 是方向向量。

ray.origin 是原始向量。

rec 代表结果对象。

rec.tHit 是匹配的值。

rec .anyHit 是布尔值。

Parameters

ray represents the ray object.
ray.direction is the direction vector.
ray.origin is the origin vector.
rec represents the result object.
rec.tHit is the value of the hit.
rec.anyHit is a boolean.

我的功能可以使用飞机：

center 和 normal 定义平面

My function has access to the plane:
center and normal defines the plane

推荐答案

正如wince所评论的那样，您还希望允许分母为否定的，否则您将错过与飞机正面的相交。但是，您仍然希望测试避免被零除，这将指示射线与平面平行。您在 t 的计算中也有多余的否定。总的来说，它应该是这样的：

As wonce commented, you want to also allow the denominator to be negative, otherwise you will miss intersections with the front face of your plane. However, you still want a test to avoid a division by zero, which would indicate the ray being parallel to the plane. You also have a superfluous negation in your computation of t. Overall, it should look like this:

float denom = normal.dot(ray.direction);
if (abs(denom) > 0.0001f) // your favorite epsilon
{
    float t = (center - ray.origin).dot(normal) / denom;
    if (t >= 0) return true; // you might want to allow an epsilon here too
}
return false;

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