Vector3: add move_towards

.tests/Vector3/move_towards.test.lua

@@ -0,0 +1,17 @@
+local Vector3 = require("worldeditadditions.utils.vector3")
+
+-- To find these numbers, in Javascript:
+-- function t(x) { return Math.sqrt((x*x)*3); }
+-- for(let i = 0; i < 1000000000; i++) { let r = t(i); if(Math.floor(r) === r) console.log(`i ${i}, r ${r}`); }
+
+
+describe("Vector3.move_towards", function()
+	it("should work with a positive vector", function()
+		local a = Vector3.new(3, 4, 5)
+		local b = Vector3.new(10, 10, 10)
+		assert.are.same(
+			Vector3.new(5.0022714374157439821, 5.7162326606420661435, 6.4301938838683883048),
+			a:move_towards(b, 3)
+		)
+	end)
+end)

worldeditadditions/utils/vector3.lua

@@ -175,6 +175,14 @@ function Vector3.limit_to(a, length)
 	return a:clone()
 end
 
+--- Return a vector that is amount distance towards b from a.
+-- @param	a		Vector3		The vector to move from.
+-- @param	b		Vector3		The vector to move towards.
+-- @param	amount	number		The amount to move.
+function Vector3.move_towards(a, b, amount)
+	return a + (b - a):limit_to(amount)
+end
+
 
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