Fail fast on missing terrain assets and recover empty renders

scripts/test-renderer.mjs

@@ -0,0 +1,140 @@
+import assert from "node:assert/strict";
+import { mkdir, readFile, writeFile } from "node:fs/promises";
+import { gunzipSync } from "node:zlib";
+import sharp from "sharp";
+import { renderSnapshot } from "../renderer/render.mjs";
+import { assertTerrainImage } from "../renderer/image-validation.mjs";
+
+// Exercise the product's rendering worker without launching a Minecraft server
+// or driving the website. A cached real export can also be supplied as argv[2].
+const output = ".cache/renderer-regression";
+const snapshot = {
+  bounds: { minX: -24, minZ: -24, maxX: 24, maxZ: 24 },
+  coverage: [],
+  blocks: [],
+};
+for (let x = -24; x < 24; x++) {
+  for (let z = -24; z < 24; z++) {
+    snapshot.blocks.push([x, 63, z, "minecraft:dirt"]);
+    snapshot.blocks.push([
+      x,
+      64,
+      z,
+      x > 12 && z < -12
+        ? "minecraft:water[level=0]"
+        : "minecraft:grass_block[snowy=false]",
+    ]);
+  }
+}
+for (let x = -4; x <= 4; x++) {
+  for (let z = -4; z <= 4; z++) {
+    for (let y = 65; y <= 71; y++) {
+      if (Math.abs(x) === 4 || Math.abs(z) === 4 || y === 71) {
+        snapshot.blocks.push([
+          x,
+          y,
+          z,
+          y === 71 ? "minecraft:oak_planks" : "minecraft:stone_bricks",
+        ]);
+      }
+    }
+  }
+}
+for (let y = 65; y <= 70; y++)
+  snapshot.blocks.push([-16, y, 0, "minecraft:oak_log[axis=y]"]);
+for (let x = -18; x <= -14; x++) {
+  for (let z = -2; z <= 2; z++) {
+    snapshot.blocks.push([
+      x,
+      71,
+      z,
+      "minecraft:oak_leaves[distance=1,persistent=true,waterlogged=false]",
+    ]);
+  }
+}
+snapshot.blocks.push([
+  5,
+  65,
+  0,
+  "minecraft:oak_stairs[facing=east,half=bottom,shape=straight,waterlogged=false]",
+]);
+let terrain = snapshot;
+let points = [
+  [-12.5, 12.5],
+  [12.5, 12.5],
+  [12.5, -12.5],
+  [-12.5, -12.5],
+  [0.5, 18.5],
+].map(([x, z], i) => ({ id: `p${i}`, x, y: 66.62, z }));
+let source = "grass, dirt, water, tree and building regression fixture";
+if (process.argv[2]) {
+  const directory = process.argv[2];
+  const manifest = JSON.parse(
+    await readFile(`${directory}/manifest.json`, "utf8"),
+  );
+  terrain = JSON.parse(
+    gunzipSync(await readFile(`${directory}/terrain.json.gz`)).toString(),
+  );
+  points = manifest.viewpoints;
+  source = "cached Paper export (no server started)";
+}
+await mkdir(output, { recursive: true });
+const report = await renderSnapshot(terrain, points, output, { size: 256 });
+assert.ok(report.meshes > 0, "terrain must produce meshes");
+assert.ok(report.emittedFaces > 0, "terrain must produce faces");
+assert.ok(report.hiddenFaces > 0, "interior terrain faces must be culled");
+assert.ok(report.geometryBytes > 0, "geometry must reach the renderer");
+assert.equal(
+  report.unsupported.some((s) =>
+    /minecraft:(stone|dirt|grass_block|water)(\[|$)/.test(s),
+  ),
+  false,
+);
+await assertTerrainImage(await readFile(`${output}/map.webp`), "Surface map");
+for (const point of points) {
+  for (const face of ["px", "nx", "py", "ny", "pz", "nz"]) {
+    const metadata = await sharp(
+      await readFile(`${output}/${point.id}/${face}.webp`),
+    ).metadata();
+    assert.equal(metadata.format, "webp");
+    assert.equal(metadata.width, 256);
+    assert.equal(metadata.height, 256);
+  }
+  await assertTerrainImage(
+    await readFile(`${output}/${point.id}/ny.webp`),
+    `Panorama ${point.id}, downward face`,
+  );
+}
+
+// The earlier renderer silently accepted this case with zero meshes and faces.
+const missingModel = {
+  ...snapshot,
+  blocks: [[0, 64, 0, "minecraft:minegeo_missing_model"]],
+};
+await assert.rejects(
+  renderSnapshot(missingModel, [points[0]], `${output}/missing-model`, {
+    size: 256,
+  }),
+  /No terrain models could be rendered/,
+);
+await writeFile(
+  `${output}/verification.json`,
+  JSON.stringify(
+    {
+      source,
+      ...report,
+      checks: [
+        "nonempty terrain",
+        "valid WebP cubemap faces",
+        "surface visible below every viewpoint",
+        "missing model rejected",
+      ],
+    },
+    null,
+    2,
+  ),
+);
+console.log(
+  "Renderer regression passed:",
+  JSON.stringify({ source, ...report }),
+);