Create functions for detecting each shape

src/detectShape.lua

@@ -1,26 +1,14 @@
 local sortCounterClockwise = require(script.Parent.sortCounterClockwise)
 local getConvexHull = require(script.Parent.getConvexHull)
-local getPerimeter = require(script.Parent.getPerimeter)
 local getPolygonArea = require(script.Parent.getPolygonArea)
-local getBoundingBox = require(script.Parent.getBoundingBox)
-local getLargestTriangle = require(script.Parent.getLargestTriangle)
-local getSideLengths = require(script.Parent.getSideLengths)
-local getTriangleArea = require(script.Parent.getTriangleArea)
 local isLine = require(script.Parent.isLine)
 local isChevron = require(script.Parent.isChevron)
+local isCircle = require(script.Parent.isCircle)
+local isRectangle = require(script.Parent.isRectangle)
+local isSquare = require(script.Parent.isSquare)
+local isTriangle = require(script.Parent.isTriangle)
 local Shape = require(script.Parent.Shape)
 
-local LINE_THRESHHOLD = 30
-local SQUARE_PERCENT = 0.60
-local RECTANGLE_PERCENT = 0.75
-local TRIANGLE_PERCENT = 0.75
-
-local CIRCLE = 4 * math.pi
-
-local function fuzzyeq(a, b, epsilon)
-	return math.abs(a - b) <= epsilon
-end
-
 local function detectShape(points: {[number]: Vector2})
 	if isLine(points) then
 		return Shape.Line
@@ -30,43 +18,15 @@ local function detectShape(points: {[number]: Vector2})
 
 	local sorted = sortCounterClockwise(points)
 	local hull = getConvexHull(sorted)
-
 	local hullArea = getPolygonArea(hull)
-	local perimeter = getPerimeter(hull)
 
-	local rectangle = getBoundingBox(hull)
-	local sides = getSideLengths(rectangle)
-	local rectangleArea = sides.X * sides.Y
-	local maxSide = math.max(sides.X, sides.Y)
-
-	local triangle = getLargestTriangle(hull)
-	local triangleArea = getTriangleArea(unpack(triangle))
-
-	-- Goes to infinity for lines and approaches 4pi for circles.
-	local thinnessRatio = perimeter^2 / hullArea
-	-- Approaches unity
-	local squareRatio = hullArea / maxSide^2
-	-- Approaches unity
-	local rectangleRatio = hullArea / rectangleArea
-	-- Approaches unity
-	local triangleRatio = triangleArea / hullArea
-
-	-- print("thinnessRatio", thinnessRatio)
-	-- print("squareRatio", squareRatio)
-	-- print("rectangleRatio", rectangleRatio)
-	-- print("triangleRatio", triangleRatio)
-
-	-- Triangles tend to have a thinnessRatio that approaches 4pi, so we also
-	-- compare with the triangleRatio to ensure we detect the correct shape/
-	if fuzzyeq(CIRCLE, thinnessRatio, 1) and triangleRatio < TRIANGLE_PERCENT then
+	if isCircle(hull, hullArea) then
 		return Shape.Circle
-	elseif squareRatio >= SQUARE_PERCENT then
+	elseif isSquare(hull, hullArea) then
 		return Shape.Square
-	elseif rectangleRatio >= RECTANGLE_PERCENT then
+	elseif isRectangle(hull, hullArea) then
 		return Shape.Rectangle
-	elseif thinnessRatio >= LINE_THRESHHOLD then
-		return Shape.Line
-	elseif triangleRatio >= TRIANGLE_PERCENT then
+	elseif isTriangle(hull, hullArea) then
 		return Shape.Triangle
 	end
 end

src/isCircle.lua

@@ -0,0 +1,17 @@
+local getPerimeter = require(script.Parent.getPerimeter)
+
+local function fuzzyeq(a, b, epsilon)
+	return math.abs(a - b) <= epsilon
+end
+
+local function isCircle(hull: { Vector2 }, hullArea: number)
+	local perimeter = getPerimeter(hull)
+
+	-- This ratio approaches 4pi for circles, so we will then compare that the
+	-- ratio is roughly close to that value for circle detection.
+	local thinnessRatio = perimeter^2 / hullArea
+
+	return fuzzyeq(4 * math.pi, thinnessRatio, 1)
+end
+
+return isCircle

src/isRectangle.lua

@@ -0,0 +1,14 @@
+local getBoundingBox = require(script.Parent.getBoundingBox)
+local getSideLengths = require(script.Parent.getSideLengths)
+
+local RECTANGLE_PERCENT = 0.75
+
+local function isRectangle(hull: { Vector2 }, hullArea: number)
+	local rectangle = getBoundingBox(hull)
+	local sides = getSideLengths(rectangle)
+	local rectangleArea = sides.X * sides.Y
+
+	return hullArea / rectangleArea >= RECTANGLE_PERCENT
+end
+
+return isRectangle

src/isSquare.lua

@@ -0,0 +1,14 @@
+local getBoundingBox = require(script.Parent.getBoundingBox)
+local getSideLengths = require(script.Parent.getSideLengths)
+
+local SQUARE_PERCENT = 0.60
+
+local function isSquare(hull: { Vector2 }, hullArea: number)
+	local rectangle = getBoundingBox(hull)
+	local sides = getSideLengths(rectangle)
+	local maxSide = math.max(sides.X, sides.Y)
+
+	return hullArea / maxSide^2 >= SQUARE_PERCENT
+end
+
+return isSquare

src/isTriangle.lua

@@ -0,0 +1,13 @@
+local getLargestTriangle = require(script.Parent.getLargestTriangle)
+local getTriangleArea = require(script.Parent.getTriangleArea)
+
+local TRIANGLE_PERCENT = 0.75
+
+local function isTriangle(hull: { Vector2 }, hullArea: number)
+	local triangle = getLargestTriangle(hull)
+	local triangleArea = getTriangleArea(unpack(triangle))
+
+	return triangleArea / hullArea >= TRIANGLE_PERCENT
+end
+
+return isTriangle