More centering fixes (#200)

* More centering fixes

* Fix types

* Break out functions and add tests

* Clean up and lint

* Add missing import

* Add added/removed boundingsphere defaults

* Update darwin e2e snapshots

* Update linux e2e snapshots

* Update names

* Better error message

* Update e2e darwin

* Update e2e linux

* Consistency tweak

* Consistency tweak

src/utils/three.test.ts

@@ -0,0 +1,84 @@
+import { BoxGeometry } from 'three'
+import { getCommonSphere, loadGeometry } from './three'
+
+describe('Function loadGeometry', () => {
+    it('loads a three geometry from a 10x10mm box', () => {
+        const box_10 = Buffer.from(
+            `
+v 0.000000 0.000000 0.000000
+v 10.000000 0.000000 0.000000
+v 0.000000 0.000000 10.000000
+v 10.000000 0.000000 10.000000
+v 10.000000 10.000000 0.000000
+v 10.000000 10.000000 10.000000
+v 0.000000 10.000000 0.000000
+v 0.000000 10.000000 10.000000
+vn 0.000000 -1.000000 0.000000
+vn 0.000000 -1.000000 0.000000
+vn 1.000000 0.000000 0.000000
+vn 1.000000 -0.000000 0.000000
+vn 0.000000 1.000000 -0.000000
+vn 0.000000 1.000000 0.000000
+vn -1.000000 0.000000 0.000000
+vn -1.000000 -0.000000 0.000000
+vn 0.000000 0.000000 -1.000000
+vn 0.000000 0.000000 -1.000000
+vn 0.000000 0.000000 1.000000
+vn 0.000000 0.000000 1.000000
+f 1//1 2//1 3//1
+f 3//2 2//2 4//2
+f 2//3 5//3 4//3
+f 4//4 5//4 6//4
+f 5//5 7//5 6//5
+f 6//6 7//6 8//6
+f 7//7 1//7 8//7
+f 8//8 1//8 3//8
+f 1//9 5//9 2//9
+f 7//10 5//10 1//10
+f 6//11 3//11 4//11
+f 6//12 8//12 3//12
+`
+        ).toString('base64')
+        const geometry = loadGeometry(box_10)
+        expect(geometry?.attributes.position.count).toEqual(6 * 2 * 3)
+        expect(geometry?.attributes.normal.count).toEqual(6 * 2 * 3)
+        expect(geometry?.attributes.uv).toBeDefined()
+        expect(geometry?.boundingSphere?.center.x).toEqual(5)
+        expect(geometry?.boundingSphere?.center.y).toEqual(5)
+        expect(geometry?.boundingSphere?.center.z).toEqual(5)
+        const diagonal = 10 * Math.sqrt(3)
+        expect(geometry?.boundingSphere?.radius).toBeCloseTo(diagonal / 2)
+    })
+
+    it('fails with an empty or invalid input', () => {
+        expect(loadGeometry('invalid')).toBeUndefined()
+    })
+})
+
+describe('Function getCommonSphere', () => {
+    // 1mm cube with "top-right" corner at origin
+    const box_1_geom = new BoxGeometry(1, 1, 1)
+    box_1_geom.translate(-1 / 2, -1 / 2, -1 / 2)
+    // 2mm cube with "bottom left" corner at origin
+    const box_2_geom = new BoxGeometry(2, 2, 2)
+    box_2_geom.translate(2 / 2, 2 / 2, 2 / 2)
+
+    it('gets the common bounding sphere between two geometries', () => {
+        const sphere = getCommonSphere(box_1_geom, box_2_geom)
+        expect(sphere.center.x).toEqual((2 - 1) / 2)
+        expect(sphere.center.y).toEqual((2 - 1) / 2)
+        expect(sphere.center.z).toEqual((2 - 1) / 2)
+        const bothDiagonals = (1 + 2) * Math.sqrt(3)
+        expect(sphere.radius).toBeCloseTo(bothDiagonals / 2)
+    })
+
+    it('gets the same bounding sphere from two identical geometries', () => {
+        box_1_geom.computeBoundingSphere()
+        const sphere_1 = getCommonSphere(box_1_geom, box_1_geom)
+        expect(sphere_1.equals(box_1_geom.boundingSphere!)).toBeTruthy()
+
+        box_2_geom.computeBoundingSphere()
+        const sphere_2 = getCommonSphere(box_2_geom, box_2_geom)
+        expect(sphere_2.equals(box_2_geom.boundingSphere!)).toBeTruthy()
+    })
+})