1 files changed, 19 insertions, 0 deletions
diff --git a/hitable.go b/hitable.go
new file mode 100644
index 0000000..a44026d
--- /dev/null
+++ b/hitable.go
@@ -0,0 +1,19 @@
+package main
+
+type Hitable interface {
+	Hit(ray Ray) bool
+}
+
+type Sphere struct {
+	center Vec3D
+	radius float64
+}
+
+func (sphere Sphere) Hit(ray Ray) bool {
+	oc := SubVec3D(ray.origin, sphere.center)
+	a := DotProduct(ray.direction, ray.direction)
+	b := 2.0 * DotProduct(oc, ray.direction)
+	c := DotProduct(oc, oc) - sphere.radius*sphere.radius
+	discriminant := b*b - 4*a*c
+	return discriminant > 0
+}