bool Sphere::intersect(Ray& ray, float& tHit, Intersection* intersect) {
vec3 e = ray.pos;
vec3 d = ray.dir;
float a = d*d;
float b = 2*d*(e - this->center);
float c = (e - this->center)*(e - this->center) - this->radius*this->radius;
if (a == 0) {
std::cout << "Ray is just a point!" << std::endl;
return false;
}
float discriminant = b*b - 4*a*c;
//float tMin = std::numeric_limits<float>::max();
if (discriminant >= 0) {
float tPos = (-b + sqrt(discriminant)) / (2.0f*a);
float tNeg = (-b - sqrt(discriminant)) / (2.0f*a);
tHit = /*(tNeg<0 && tPos>0)? tPos :*/ tNeg;
if (tHit >= ray.tMax || tHit <= ray.tMin) return false;
intersect->point = vec3(transform * vec4(ray.evaluate(tHit),1),VW);
intersect->normal = vec3(transformTI * vec4(intersect->point - this->center, 0),VW).normalize();
//if (tNeg<0 && tPos>0) {
// intersect->normal = -1*intersect->normal;
//}
intersect->shape = this;
return true;
}
return false;
}
bool Triangle::intersect(Ray& ray, float& tHit, Intersection* intersect) {
vec3 eye = ray.pos;
vec3 dir = ray.dir;
float a = v1[VX] - v2[VX], d = v1[VX] - v3[VX], g = dir[VX];
float b = v1[VY] - v2[VY], e = v1[VY] - v3[VY], h = dir[VY];
float c = v1[VZ] - v2[VZ], f = v1[VZ] - v3[VZ], i = dir[VZ];
float j = v1[VX]-eye[VX];
float k = v1[VY]-eye[VY];
float l = v1[VZ]-eye[VZ];
float m = (a*(e*i - h*f) + b*(g*f - d*i) + c*(d*h - e*g));
float t = (f*(a*k - j*b) + e*(j*c - a*l) + d*(b*l - k*c))/-m;
if (t < ray.tMin || t > ray.tMax) return false;
float gamma = (i*(a*k - j*b) + h*(j*c - a*l) + g*(b*l - k*c)) / m;
if (gamma < 0 || gamma > 1) return false;
float beta = (j*(e*i - h*f) + k*(g*f - d*i) + l*(d*h - e*g))/m;
if (beta < 0 || beta > 1-gamma) return false;
tHit = t;
intersect->point = ray.evaluate(t);
intersect->shape = this;
float mag = (v1-intersect->point).length() + (v2-intersect->point).length() + (v3-intersect->point).length();
intersect->normal = (((v1-intersect->point).length()/mag)*n1 + ((v2-intersect->point).length()/mag)*n2 + ((v3-intersect->point).length()/mag)*n3).normalize();
return true;
}
std::unique_ptr<Intersection> Sphere::intersect(const Ray& ray) {
auto p = ray.p - center;
auto d = ray.d;
float dp = d.dot(p);
float dd = d.dot(d);
float pp = p.dot(p);
float discr = (dp*dp) - (dd*(pp-(radius*radius)));
if (discr < 0) {
return nullptr;
} else {
// Find both intersections
float t0 = (-dp - sqrt(discr)) / dd;
float t1 = (-dp + sqrt(discr)) / dd;
// Entire sphere is behind camera
if (t1 < 0)
return nullptr;
// Front of sphere is behind camera
float t = t0 < 0 ? t1 : t0;
// Calculate surface normal
auto n = (ray.evaluate(t) - center).normalized();
return std::unique_ptr<Intersection>(new Intersection(this, n, t));
}
}
glm::vec3 Sphere::collisionNormal( const Ray& ray ) const
{
float time = intersect( ray );
if( time == inf )
return glm::vec3();
return glm::normalize( ray.evaluate( time ) - center );
}
Color Scene::shade(const Ray& ray, const Intersection& hit, int depth, bool shadows, bool kd) const {
auto p = ray.evaluate(hit.t);
auto n = hit.normal;
return (hit.hit)->shade(ray, p, n, light, *this, depth, shadows, kd);
}
