Refine Gwanaksan summit marker proportions and inscription

tests/summit-marker.test.ts

@@ -0,0 +1,32 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { BoxGeometry, Group, Mesh, MeshStandardMaterial, Vector3 } from 'three';
+import { createSummitMarker } from '../src/scene/summitMarker.ts';
+
+test('marker seats its foot on sloping bedrock without deforming the stone', () => {
+  const asset = new Group();
+  const mesh = new Mesh(new BoxGeometry(4, 4, 2), new MeshStandardMaterial());
+  mesh.position.y = 2;
+  asset.add(mesh);
+  const groundAt = (x: number, z: number) => 12 + .3*x - .2*z;
+  const rock = new MeshStandardMaterial();
+  const marker = createSummitMarker(asset, {x:0,z:0}, groundAt, rock);
+  marker.group.updateMatrixWorld(true);
+  const position = mesh.geometry.getAttribute('position');
+  const point = new Vector3();
+  let nearestContact = Infinity;
+  for (let i=0; i<position.count; i++) {
+    point.fromBufferAttribute(position,i).applyMatrix4(mesh.matrixWorld);
+    if (position.getY(i)<0) {
+      const burial = groundAt(point.x,point.z)-point.y;
+      assert.ok(burial > .05, `base must stay below terrain: ${burial}`);
+      assert.equal(position.getY(i),-2,'base geometry remains unchanged');
+      nearestContact = Math.min(nearestContact,burial);
+    } else {
+      assert.equal(position.getY(i),2,'upper geometry remains unchanged');
+    }
+  }
+  assert.ok(nearestContact < .3,'the stone is seated close to its lowest contact');
+  marker.dispose();
+  rock.dispose();
+});