fix: 优化空格播放和截图角色标签对不上

src/editor/canvas/SceneRoot.test.tsx

@@ -1,4 +1,5 @@
 import { fireEvent, render, screen, waitFor } from "@testing-library/react";
+import { readFileSync } from "node:fs";
 import { Box3, DoubleSide, Vector3 } from "three";
 import { afterEach, beforeEach, vi } from "vitest";
 import { VIEWPORT_CAMERA_VISUAL_SCALE } from "../schema/cameraGeometry";
@@ -274,6 +275,16 @@ it("uses the requested dark ground surface color", () => {
   expect(groundMaterial?.outerHTML.toLowerCase()).toContain("polygonoffsetunits=\"1\"");
 });
 
+it("paints the ground with the ground color from the scene settings", () => {
+  useDirectorStore.getState().updateScene({ groundColor: "#204060" });
+
+  const { container } = render(<SceneRoot />);
+
+  // 地面颜色和天空颜色一样是工程设置：面板上改了颜色，视口里的地面材质就得跟着变
+  expect(container.querySelector('meshbasicmaterial[color="#204060"]')).toBeInTheDocument();
+  expect(container.querySelector('meshbasicmaterial[color="#303640"]')).not.toBeInTheDocument();
+});
+
 it("keeps the ground visible when the view drops below the ground plane", () => {
   const { container } = render(<SceneRoot />);
   const groundMaterial = container.querySelector('meshbasicmaterial[color="#303640"]');
@@ -680,6 +691,21 @@ it("renders solid trajectory spheres and a smooth curve through the waypoints",
   expect(container.querySelectorAll('mesh[name^="trajectory-point-"]')).toHaveLength(2);
 });
 
+it("keeps the trajectory marker material writing depth so an opaque ground cannot hide it", () => {
+  // 这条约束落在材质参数上（jsdom 里 <mesh> / <meshBasicMaterial> 只是普通 DOM 节点，
+  // depthWrite 这种 unknown 布尔属性不会落到 DOM 上，跑不出来），所以按源码契约断言。
+  const source = readFileSync("src/editor/canvas/SceneRoot.tsx", "utf8");
+  const markerMaterialLine = source
+    .split("\n")
+    .find((line) => line.includes("<meshBasicMaterial color={selected ? TRAJECTORY_SELECTED_COLOR : color}"));
+
+  expect(markerMaterialLine).toBeDefined();
+  // 地面是 transparent 材质：即使透明度为 1 也走透明通道、排在所有不透明物体之后渲染。
+  // 小球一旦不写深度（depthWrite={false}），地面会整片盖住它 ——
+  // 表现就是「地面透明度为 1 时看不到轨迹点」。
+  expect(markerMaterialLine).not.toContain("depthWrite");
+});
+
 it("puts a walking character at its trajectory sample for the current playhead", () => {
   useDirectorStore.getState().addTrajectoryPoint("char_default_a", [8, 0, 0]);
   // 单点轨迹：0s 在角色起始位置，时间轴末尾（5s）到达该轨迹点