在过去的几天里，我第一次破解了光线追踪器。但是，有一些怪癖困扰着我，我真的不知道如何解决。从一开始就存在的一个是场景中的球体形状——渲染时，它们实际上看起来像椭圆形。当然，场景中有透视，但最终的形状仍然看起来很奇怪。我附上了一个示例渲染，我遇到的问题在图像左下角的反射球上特别明显。
我真的不知道是什么原因造成的。它可能是射线-球体相交代码，如下所示：
bool Sphere::intersect(Ray ray, glm::vec3& hitPoint) {
//Compute A, B and C coefficients
float a = glm::dot(ray.dir, ray.dir);
float b = 2.0 * glm::dot(ray.dir, ray.org-pos);
float c = glm::dot(ray.org-pos, ray.org-pos) - (rad * rad);
// Find discriminant
float disc = b * b - 4 * a * c;
// if discriminant is negative there are no real roots, so return
// false as ray misses sphere
if (disc < 0)
return false;
// compute q
float distSqrt = sqrt(disc);
float q;
if (b < 0)
q = (-b - distSqrt)/2.0;
else
q = (-b + distSqrt)/2.0;
// compute t0 and t1
float t0 = q / a;
float t1 = c / q;
// make sure t0 is smaller than t1
if (t0 > t1) {
// if t0 is bigger than t1 swap them around
float temp = t0;
t0 = t1;
t1 = temp;
}
// if t1 is less than zero, the object is in the ray's negative direction
// and consequently the ray misses the sphere
if (t1 < 0)
return false;
// if t0 is less than zero, the intersection point is at t1
if (t0 < 0) {
hitPoint = ray.org + t1 * ray.dir;
return true;
} else { // else the intersection point is at t0
hitPoint = ray.org + t0 * ray.dir;
return true;
}
}
或者它可能是另一回事。有人有想法吗？非常感谢！