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Add simple sphere.

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Faerbit 2020-06-03 23:14:18 +02:00
parent 6cbaaabd6a
commit 9f4868917d
1 changed files with 11 additions and 0 deletions
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wtracer.cpp
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@ -4,7 +4,18 @@
#include "vec3.h"
#include "ray.h"
bool hit_sphere(const Point3& center, double radius, const Ray& r) {
Vec3 oc = r.origin() - center;
auto a = dot(r.direction(), r.direction());
auto b = 2.0 * dot(oc, r.direction());
auto c = dot(oc, oc) - radius * radius;
auto disciminant = b*b - 4*a*c;
return disciminant > 0;
}
Color ray_color(const Ray& r) {
if (hit_sphere(Point3(0, 0, -1), 0.5, r))
return Color(1, 0, 0);
Vec3 unit_direction = unit_vector(r.direction());
auto t = 0.5 * (unit_direction.y() + 1.0);
return (1.0 - t) * Color(1.0, 1.0, 1.0) + t * Color(0.5, 0.7, 1.0);