From cfa086ce467f02489a0243209fae3b3eed6f1020 Mon Sep 17 00:00:00 2001
From: Starbeamrainbowlabs <sbrl@starbeamrainbowlabs.com>
Date: Sat, 26 Jun 2021 15:47:53 +0100
Subject: [PATCH] Vector3: add dot product

---
 .tests/Vector3/dot.test.lua          | 36 ++++++++++++++++++++++++++++
 worldeditadditions/utils/vector3.lua | 12 ++++++++++
 2 files changed, 48 insertions(+)
 create mode 100644 .tests/Vector3/dot.test.lua

diff --git a/.tests/Vector3/dot.test.lua b/.tests/Vector3/dot.test.lua
new file mode 100644
index 0000000..3f6f6b3
--- /dev/null
+++ b/.tests/Vector3/dot.test.lua
@@ -0,0 +1,36 @@
+local Vector3 = require("worldeditadditions.utils.vector3")
+
+describe("Vector3.dot", function()
+	it("should work with a positive vector", function()
+		local a = Vector3.new(3, 3, 3)
+		local b = Vector3.new(4, 5, 6)
+		assert.are.equal(
+			45,
+			a:dot(b)
+		)
+	end)
+	it("should work with a negative vector", function()
+		local a = Vector3.new(-4, -4, -4)
+		local b = Vector3.new(4, 5, 6)
+		assert.are.equal(
+			-60,
+			a:dot(b)
+		)
+	end)
+	it("should work with a mixed vector", function()
+		local a = Vector3.new(-3, 3, -3)
+		local b = Vector3.new(7, 8, 9)
+		assert.are.equal(
+			-24,
+			a:dot(b)
+		)
+	end)
+	it("should work with the dot_product alias", function()
+		local a = Vector3.new(-3, 3, -3)
+		local b = Vector3.new(7, 8, 9)
+		assert.are.equal(
+			-24,
+			a:dot_product(b)
+		)
+	end)
+end)
diff --git a/worldeditadditions/utils/vector3.lua b/worldeditadditions/utils/vector3.lua
index 7fa33df..a81464c 100644
--- a/worldeditadditions/utils/vector3.lua
+++ b/worldeditadditions/utils/vector3.lua
@@ -162,6 +162,18 @@ function Vector3.length(a)
 	return math.sqrt(a:length_squared())
 end
 
+--- Calculates the dot product of this vector and another vector.
+-- @param	a		Vector3		The first vector to operate on.
+-- @param	a		Vector3		The second vector to operate on.
+-- @returns	number	The dot product of this vector as a scalar value.
+function Vector3.dot(a, b)
+	return a.x * b.x + a.y * b.y + a.z * b.z;
+end
+--- Alias of Vector3.dot.
+function Vector3.dot_product(a, b)
+	return Vector3.dot(a, b)
+end
+
 --- Returns a new vector whose length clamped to the given length.
 -- The direction in which the vector is pointing is not changed.
 -- @param	a		Vector3		The vector to operate on.