Remove collision from water

client/entity/entity.ts

@@ -1,4 +1,3 @@
-import { AIR } from "$/common/constants.ts";
 import { move_body } from "$/common/physics.ts";
 import type { ClientLevel } from "../level/client_level.ts";
 
@@ -73,7 +72,7 @@ export abstract class Entity {
 
 	// falls and moves by its velocity for one tick, see move_body
 	move() {
-		const collisions = move_body(this, this.gravity, (x, y, z) => this.level.get_block(x, y, z) !== AIR);
+		const collisions = move_body(this, this.gravity, (x, y, z) => this.level.has_collision(x, y, z));
 		this.colliding_x = collisions.x;
 		this.colliding_y = collisions.y;
 		this.colliding_z = collisions.z;

client/level/client_level.ts

@@ -254,6 +254,12 @@ export class ClientLevel {
 		return chunk.blocks[index] & ID_MASK;
 	}
 
+	// whether entities bump into the block there. unloaded chunks count as solid, so nothing falls out of the world
+	has_collision(x: number, y: number, z: number) {
+		const block = this.get_block(x, y, z);
+		return block === VOID || (block !== AIR && (this.#blocks[block]?.has_collision ?? true));
+	}
+
 	// only changes what this client shows, drops and everything else happen on the server
 	break_block(x: number, y: number, z: number) {
 		const block_chunk_x = Math.floor(x / CHUNK_SIZE);

mods/bworld/blocks/chest.json

@@ -3,7 +3,6 @@
 	"block": {
 		"id": "bworld:chest",
 		"textures": "bworld:planks",
-		"collision": false,
 		"mining": {
 			"toughness": 8,
 			"tool": "axe"

mods/bworld/blocks/dirt.json

@@ -3,7 +3,6 @@
 	"block": {
 		"id": "bworld:dirt",
 		"textures": "bworld:dirt",
-		"collision": false,
 		"mining": {
 			"toughness": 2,
 			"tool": "shovel"

mods/bworld/blocks/grass.json

@@ -7,7 +7,6 @@
 			"bottom": "bworld:dirt",
 			"side": "bworld:grass_side"
 		},
-		"collision": false,
 		"mining": {
 			"toughness": 2,
 			"tool": "shovel"

mods/bworld/blocks/hoed_dirt.json

@@ -7,7 +7,6 @@
 			"top": "bworld:hoed_dirt",
 			"bottom": "bworld:dirt"
 		},
-		"collision": false,
 		"mining": {
 			"toughness": 5,
 			"tool": "shovel"

server/game/game_server.ts

@@ -829,7 +829,7 @@ export class GameServer {
 		if (this.#entities.size === 0) {
 			return;
 		}
-		const is_solid = (x: number, y: number, z: number) => this.world.get_block_nid(x, y, z) !== AIR;
+		const is_solid = (x: number, y: number, z: number) => this.world.has_collision(x, y, z);
 
 		const active = [...this.#entities.values()].filter((entity) => this.#near_any_player(entity.x, entity.z));
 		for (const entity of active) {

server/game/world.ts

@@ -113,6 +113,11 @@ export class ServerWorld {
 		return this.#get_chunk(chunk_x, chunk_z)[index_in_chunk(x, y, z, chunk_x, chunk_z)];
 	}
 
+	// whether entities bump into the block there, water and other blocks with "collision": false don't
+	has_collision(x: number, y: number, z: number) {
+		return this.get_block_info(x, y, z)?.has_collision ?? false;
+	}
+
 	get_block_info(x: number, y: number, z: number): BlockRegistry | undefined {
 		const nid = this.get_block_nid(x, y, z);
 		return nid === AIR ? undefined : EverythingRegistry.get_by_id<BlockRegistry>("blocks", nid);

tests/item_entity_test.ts

@@ -114,3 +114,16 @@ Deno.test("q throws one of an item the way the player looks, ctrl throws the who
 	send(1, { type: "drop_item", container: "crafting", index: 9, all: true });
 	assertEquals(game.item_entities().length, 2);
 });
+
+Deno.test("water has no collision, items sink through it to the floor", async () => {
+	const { game, join } = await test_game("mods");
+	join(1, "alice");
+	build_floor(game);
+	for (let y = 100; y <= 102; y++) {
+		game.set_block(6, y, 0, "bworld:water");
+	}
+	const item = game.spawn_item(6.5, 104, 0.5, new ItemStack("bworld:dirt"));
+	for (let i = 0; i < 40; i++) game.tick();
+	assert(item.on_ground);
+	assertEquals(item.y, 100, "on the stone under the water");
+});