yourpart3/frontend/scripts/test-character-appearance.mjs

import assert from 'node:assert/strict';
import test from 'node:test';
import { BufferAttribute, BufferGeometry, Group, Mesh, MeshStandardMaterial, PlaneGeometry, Vector2, Vector3 } from 'three';
import {
  applyCharacterAppearance, captureAppearanceEditor, clearAppearanceMarks, finishAppearanceStroke,
  getAppearanceStats, paintAppearanceRegion, prepareAppearanceEditor, restoreAppearanceEditor,
} from '../src/utils/characterAppearance.js';

function fixture(material = new MeshStandardMaterial(), geometry = new PlaneGeometry(2, 2)) {
  const model = new Group();
  const mesh = new Mesh(geometry, material);
  model.add(mesh);
  model.updateMatrixWorld(true);
  return { model, mesh };
}
function shaderFor(material) {
  const shader = { uniforms: {}, vertexShader: '#include <uv_vertex>', fragmentShader: '#include <map_fragment>\n#include <emissivemap_fragment>' };
  material.onBeforeCompile(shader);
  return shader;
}
function sampleMask(material, u, v) {
  const { data, width, height } = shaderFor(material).uniforms.falukantRegionMask.value.image;
  const index = (Math.floor(v * height) * width + Math.floor(u * width)) * 4;
  return Array.from(data.subarray(index, index + 2));
}
function paint(mesh, point, radius = .16, region = 'iris') {
  return paintAppearanceRegion({ object: mesh, faceIndex: 0, point, uv: new Vector2(point.x / 2 + .5, point.y / 2 + .5) }, radius, region, new Vector3(0, 0, -1));
}

test('a small iris brush paints pixels within a large triangle without changing any geometry', async () => {
  const { model, mesh } = fixture();
  const original = mesh.geometry;
  const originalIndex = original.index.array.slice();
  const originalUV = original.getAttribute('uv').array.slice();
  await prepareAppearanceEditor(model, { maskSize: 128 });
  const snapshot = captureAppearanceEditor(model);
  assert.equal(paint(mesh, new Vector3(.35, .1, 0)), true);
  const stats = getAppearanceStats(model);
  assert.ok(stats.iris > 10 && stats.iris < 500, 'The brush must not color the whole triangle');
  assert.ok(sampleMask(mesh.material, .675, .55)[1] > 200);
  assert.deepEqual(sampleMask(mesh.material, .85, .75), [0, 0], 'Skin outside the brush stays unmarked');
  assert.equal(mesh.geometry, original);
  assert.deepEqual(mesh.geometry.index.array, originalIndex);
  assert.deepEqual(mesh.geometry.getAttribute('uv').array, originalUV);
  finishAppearanceStroke(model);
  restoreAppearanceEditor(snapshot);
  assert.deepEqual(getAppearanceStats(model), { body: 128 * 128, hair: 0, iris: 0 });
});

test('hair and iris colors are independent across instances and can be disabled', async () => {
  const originalMaterial = new MeshStandardMaterial();
  const first = fixture(originalMaterial), second = fixture(originalMaterial);
  await prepareAppearanceEditor(first.model, { maskSize: 32 });
  await prepareAppearanceEditor(second.model, { maskSize: 32 });
  applyCharacterAppearance(first.model, { hairColor: '#ff0000', eyeColor: '#0000ff' });
  applyCharacterAppearance(second.model, { hairColor: '#00ff00' });
  const firstShader = shaderFor(first.mesh.material), secondShader = shaderFor(second.mesh.material);
  assert.equal(firstShader.uniforms.falukantHairColor.value.getHexString(), 'ff0000');
  assert.equal(firstShader.uniforms.falukantIrisColor.value.getHexString(), '0000ff');
  assert.equal(secondShader.uniforms.falukantHairColor.value.getHexString(), '00ff00');
  assert.notEqual(firstShader.uniforms.falukantRegionMask.value, secondShader.uniforms.falukantRegionMask.value);
  paint(first.mesh, new Vector3(), .2, 'hair');
  assert.equal(getAppearanceStats(second.model).hair, 0);
  applyCharacterAppearance(first.model, { hairColor: '#cccccc', eyeColor: null });
  assert.equal(firstShader.uniforms.falukantHairColor.value.getHexString(), 'cccccc');
  assert.equal(firstShader.uniforms.falukantIrisEnabled.value, 0);
  assert.equal(secondShader.uniforms.falukantHairColor.value.getHexString(), '00ff00');
});

test('an iris brush spans separate UV islands along a shared surface edge', async () => {
  const geometry = new BufferGeometry();
  geometry.setAttribute('position', new BufferAttribute(new Float32Array([
    -1, -1, 0, 1, -1, 0, -1, 1, 0,
    1, -1, 0, 1, 1, 0, -1, 1, 0,
  ]), 3));
  geometry.setAttribute('uv', new BufferAttribute(new Float32Array([
    0, 0, .4, 0, 0, 1,
    .6, 0, 1, 1, .6, 1,
  ]), 2));
  const { model, mesh } = fixture(undefined, geometry);
  await prepareAppearanceEditor(model, { maskSize: 128 });
  assert.equal(paint(mesh, new Vector3(), .3), true);
  const { data, width } = shaderFor(mesh.material).uniforms.falukantRegionMask.value.image;
  const columns = [];
  for (let i = 0; i < data.length; i += 4) if (data[i + 1]) columns.push((i / 4) % width);
  assert.ok(columns.some(x => x < width * .4));
  assert.ok(columns.some(x => x > width * .6));
});

test('erasing is pixel-precise, undo restores it and legacy material labels remain editable', async () => {
  const material = new MeshStandardMaterial();
  material.userData.falukantAppearance = { version: 1, region: 'iris', source: 'material-0' };
  const { model, mesh } = fixture(material);
  await prepareAppearanceEditor(model, { maskSize: 64 });
  assert.equal(getAppearanceStats(model).iris, 64 * 64);
  const before = captureAppearanceEditor(model);
  assert.equal(paint(mesh, new Vector3(), .2, 'body'), true);
  finishAppearanceStroke(model);
  assert.deepEqual(sampleMask(mesh.material, .5, .5), [0, 0]);
  assert.equal(sampleMask(mesh.material, .9, .9)[1], 255);
  restoreAppearanceEditor(before);
  assert.equal(getAppearanceStats(model).iris, 64 * 64);
  const clearSnapshot = captureAppearanceEditor(model);
  clearAppearanceMarks(model);
  finishAppearanceStroke(model);
  assert.equal(getAppearanceStats(model).iris, 0);
  restoreAppearanceEditor(clearSnapshot);
  assert.equal(getAppearanceStats(model).iris, 64 * 64);
  await prepareAppearanceEditor(model);
  assert.equal(getAppearanceStats(model).iris, 64 * 64);
});