From: Maximilian Friedersdorff <max@friedersdorff.com>
Date: Mon, 11 Mar 2019 10:17:54 +0000 (+0000)
Subject: Initial Commit:  Vec type, Cross, Dot and Sub methods
X-Git-Url: https://git.friedersdorff.com/?a=commitdiff_plain;h=2aa7511dfa09910d809a85fd41023d42301af664;p=max%2Fvector.go.git

Initial Commit:  Vec type, Cross, Dot and Sub methods
---

2aa7511dfa09910d809a85fd41023d42301af664
diff --git a/README.rst b/README.rst
new file mode 100644
index 0000000..e5f0b56
--- /dev/null
+++ b/README.rst
@@ -0,0 +1,3 @@
+vector.go
+=========
+Some utilities for dealing with 3D vectors.
diff --git a/vector.go b/vector.go
new file mode 100644
index 0000000..456b2e2
--- /dev/null
+++ b/vector.go
@@ -0,0 +1,22 @@
+// vector provides a Vec type and methods for performing vector arithmetic
+package vector
+
+// 3 dimensional vector
+type Vec struct {
+  X, Y, Z  float64
+}
+
+// Cross returns the cross product between vectors v and o
+func (v Vec) Cross(o Vec) Vec {
+  return Vec{v.Y*o.Z - v.Z*o.Y, v.Z*o.X - v.X*o.Z, v.X*o.Y - v.Y*o.X}
+}
+
+// Doc returns the dot product between vectors v and o
+func (v Vec) Dot(o Vec) float64 {
+  return v.X*o.X + v.Y*o.Y + v.Z*o.Z
+}
+
+// sub subtracts o from v
+func (v Vec) Sub(o Vec) Vec {
+  return Vec{v.X - o.X, v.Y - o.Y, v.Z - o.Z}
+}