From 19124e8c21b86dccb9e9d874c614aacb05c0fd4a Mon Sep 17 00:00:00 2001
From: Martin Lehoux <martin@lehoux.net>
Date: Sat, 4 Apr 2020 15:30:25 -0700
Subject: feat - Display sphere

---
 hitable.go | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 hitable.go

(limited to 'hitable.go')

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
+}
-- 
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