hand adjsutments

tests/hand-aim.test.mjs

@@ -0,0 +1,49 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+
+import { computePalmAimRay } from '../vr180player/xr/hand-aim.js';
+
+const wrist = { x: 0, y: 0, z: 0 };
+const middleMetacarpal = { x: 0, y: 0.1, z: 0 };
+const ringMetacarpal = { x: 0.025, y: 0.1, z: 0 };
+
+test('computePalmAimRay points out from a right palm instead of following the index finger', () => {
+	const ray = computePalmAimRay({
+		handedness: 'right',
+		indexMetacarpal: { x: -0.035, y: 0.1, z: 0 },
+		middleMetacarpal,
+		pinkyMetacarpal: { x: 0.055, y: 0.1, z: 0 },
+		ringMetacarpal,
+		wrist
+	});
+
+	assert.ok(ray);
+	assert.equal(Math.round(ray.direction.x * 1000) / 1000, 0);
+	assert.equal(Math.round(ray.direction.y * 1000) / 1000, 0);
+	assert.equal(Math.round(ray.direction.z * 1000) / 1000, -1);
+	assert.equal(Math.round(ray.origin.z * 1000) / 1000, -0.035);
+});
+
+test('computePalmAimRay flips the palm normal for a left hand', () => {
+	const ray = computePalmAimRay({
+		handedness: 'left',
+		indexMetacarpal: { x: 0.035, y: 0.1, z: 0 },
+		middleMetacarpal,
+		pinkyMetacarpal: { x: -0.055, y: 0.1, z: 0 },
+		ringMetacarpal: { x: -0.025, y: 0.1, z: 0 },
+		wrist
+	});
+
+	assert.ok(ray);
+	assert.equal(Math.round(ray.direction.z * 1000) / 1000, -1);
+});
+
+test('computePalmAimRay returns null when palm joints cannot define a stable ray', () => {
+	assert.equal(computePalmAimRay({ handedness: 'right', wrist }), null);
+	assert.equal(computePalmAimRay({
+		handedness: 'right',
+		indexMetacarpal: { x: 0, y: 0.1, z: 0 },
+		pinkyMetacarpal: { x: 0, y: 0.1, z: 0 },
+		wrist
+	}), null);
+});