Tree generation

tests/worldgen_test.ts

@@ -38,3 +38,38 @@ Deno.test("new players spawn on dry land, all in the same place", async () => {
 	// the same place for the next new player
 	assertEquals(join(2, "bob").spawn, joined.spawn);
 });
+
+Deno.test("trees grow on the ground, never closer than 4 blocks, even across chunk borders", async () => {
+	const { game } = await test_game("mods");
+	const ids = game.world.block_ids;
+	const log = ids["bworld:log"];
+	const ground = new Set([ids["bworld:grass"], ids["bworld:dirt"], ids["bworld:snow"]]);
+
+	// the bottom log of every trunk, in world coordinates
+	const trunks: [number, number][] = [];
+	let spilled_leaves = 0;
+	for (let cx = -6; cx < 6; cx++) {
+		for (let cz = -6; cz < 6; cz++) {
+			const { blocks, spills } = generate_raw_chunk(cx, cz, "trees-test", ids);
+			blocks.forEach((block, i) => {
+				if (block === log && ground.has(blocks[i - CHUNK_AREA])) {
+					const x = cx * 16 + (i % 16);
+					const z = cz * 16 + Math.floor(i / 16) % 16;
+					trunks.push([x, z]);
+				}
+			});
+			for (let i = 3; i < spills.length; i += 4) {
+				if (spills[i] === ids["bworld:leaves"]) spilled_leaves++;
+			}
+		}
+	}
+
+	assert(trunks.length > 50, `only ${trunks.length} trees`);
+	assert(spilled_leaves > 0, "leaves reach into neighboring chunks");
+	for (let a = 0; a < trunks.length; a++) {
+		for (let b = a + 1; b < trunks.length; b++) {
+			const distance = Math.hypot(trunks[a][0] - trunks[b][0], trunks[a][1] - trunks[b][1]);
+			assert(distance >= 4, `trees at ${trunks[a]} and ${trunks[b]} are ${distance.toFixed(1)} apart`);
+		}
+	}
+});