From 386eb28f113f2eb7161d561c2f8111a7625ef5a7 Mon Sep 17 00:00:00 2001
From: Sander Schobers <sander@schobers.eu>
Date: Wed, 18 Jul 2018 20:05:06 +0200
Subject: [PATCH] Added Matrix3x3F32 and Vector3F32. Added shorthand for
 creating a PointF32.

---
 matrix3x3f32.go | 67 +++++++++++++++++++++++++++++++++++++++++++++++++
 pointf32.go     |  5 ++++
 vector3f32.go   | 11 ++++++++
 3 files changed, 83 insertions(+)
 create mode 100644 matrix3x3f32.go
 create mode 100644 vector3f32.go

diff --git a/matrix3x3f32.go b/matrix3x3f32.go
new file mode 100644
index 0000000..91fd22e
--- /dev/null
+++ b/matrix3x3f32.go
@@ -0,0 +1,67 @@
+package geom
+
+// Matrix3x3F32 is an matrix with 3 vectors, i, j and k (floating point, 32 bits).
+type Matrix3x3F32 struct {
+	I Vector3F32
+	J Vector3F32
+	K Vector3F32
+}
+
+// Mx3x3F32 is a shorthand function to create a matrix.
+func Mx3x3F32(i, j, k Vector3F32) Matrix3x3F32 {
+	return Matrix3x3F32{i, j, k}
+}
+
+// ScaleV scales the matrix m by vector v.
+func (m Matrix3x3F32) ScaleV(v Vector3F32) Matrix3x3F32 {
+	return Matrix3x3F32{
+		Vec3F32(v.X*m.I.X, v.X*m.I.Y, v.X*m.I.Z),
+		Vec3F32(v.Y*m.I.X, v.Y*m.I.Y, v.Y*m.I.Z),
+		Vec3F32(v.Z*m.I.X, v.Z*m.I.Y, v.Z*m.I.Z),
+	}
+}
+
+// MulV multiplies the matrix m with vector v.
+func (m Matrix3x3F32) MulV(v Vector3F32) Vector3F32 {
+	return Vec3F32(
+		v.X*m.I.X+v.Y*m.J.X+v.Z*m.K.X,
+		v.X*m.I.Y+v.Y*m.J.Y+v.Z*m.K.Y,
+		v.X*m.I.Z+v.Y*m.J.Z+v.Z*m.K.Z)
+}
+
+// MulM multiplies the matrix m with matrix n.
+func (m Matrix3x3F32) MulM(n Matrix3x3F32) Matrix3x3F32 {
+	return Matrix3x3F32{
+		Vec3F32(
+			n.I.X*m.I.X+n.I.Y*m.J.X+n.I.Z*m.K.X,
+			n.I.X*m.I.Y+n.I.Y*m.J.Y+n.I.Z*m.K.Y,
+			n.I.X*m.I.Z+n.I.Y*m.J.Z+n.I.Z*m.K.Z),
+		Vec3F32(
+			n.J.X*m.I.X+n.J.Y*m.J.X+n.J.Z*m.K.X,
+			n.J.X*m.I.Y+n.J.Y*m.J.Y+n.J.Z*m.K.Y,
+			n.J.X*m.I.Z+n.J.Y*m.J.Z+n.J.Z*m.K.Z),
+		Vec3F32(
+			n.K.X*m.I.X+n.K.Y*m.J.X+n.K.Z*m.K.X,
+			n.K.X*m.I.Y+n.K.Y*m.J.Y+n.K.Z*m.K.Y,
+			n.K.X*m.I.Z+n.K.Y*m.J.Z+n.K.Z*m.K.Z),
+	}
+}
+
+// Det calculates the determinant of the matrix m.
+func (m Matrix3x3F32) Det() float32 {
+	return m.I.X*m.J.Y*m.K.Z +
+		m.J.X*m.K.Y*m.I.Z +
+		m.K.X*m.I.Y*m.J.Z -
+		m.K.X*m.J.Y*m.I.Z -
+		m.J.X*m.I.Y*m.K.Z -
+		m.I.X*m.K.Y*m.J.Z
+}
+
+// Adj calculates the adjugate matrix of matrix m.
+func (m Matrix3x3F32) Adj() Matrix3x3F32 {
+	return Mx3x3F32(
+		Vec3F32(m.J.Y*m.K.Z-m.K.Y*m.J.Z, m.K.Y*m.I.Z-m.I.Y*m.K.Z, m.I.Y*m.J.Z-m.J.Y*m.I.Z),
+		Vec3F32(m.K.X*m.J.Z-m.J.X*m.K.Z, m.I.X*m.K.Z-m.K.X*m.I.Z, m.J.X*m.I.Z-m.I.X*m.J.Z),
+		Vec3F32(m.J.X*m.K.Y-m.K.X*m.J.Y, m.K.X*m.I.Y-m.I.X*m.K.Y, m.I.X*m.J.Y-m.J.X*m.I.Y),
+	)
+}
diff --git a/pointf32.go b/pointf32.go
index 5bb2096..3fd0a87 100644
--- a/pointf32.go
+++ b/pointf32.go
@@ -4,3 +4,8 @@ package geom
 type PointF32 struct {
 	X, Y float32
 }
+
+// PtF32 is a shorthand function to create a point.
+func PtF32(x, y float32) PointF32 {
+	return PointF32{x, y}
+}
diff --git a/vector3f32.go b/vector3f32.go
new file mode 100644
index 0000000..cbe8717
--- /dev/null
+++ b/vector3f32.go
@@ -0,0 +1,11 @@
+package geom
+
+// Vector3F32 is a vector of size 3 (floating point, 32 bits).
+type Vector3F32 struct {
+	X, Y, Z float32
+}
+
+// Vec3F32 is a shorthand function to create a vector.
+func Vec3F32(x, y, z float32) Vector3F32 {
+	return Vector3F32{x, y, z}
+}