spacetime_tiled

Load Tiled maps into SpacetimeDB for multiplayer games.

This library parses TMX files and stores them in SpacetimeDB tables. Since SpacetimeDB modules run in WASM without filesystem access, it includes an in-memory XML parser that works with embedded map data or content sent from clients.

Quick Start

Add to your server module's Cargo.toml:

[dependencies]
spacetimedb = "1.4.0"
spacetime_tiled = "0.1"

[lib]
crate-type = ["cdylib"]

In your server code:

use spacetimedb::{reducer, ReducerContext};
pub use spacetime_tiled::*;

#[reducer]
pub fn load_map(ctx: &ReducerContext) -> Result<(), String> {
    // Embed the TMX file at compile time
    const MAP_DATA: &str = include_str!("../assets/map.tmx");

    // Parse and store in database
    load_tmx_map_from_str(ctx, "level1", MAP_DATA)?;
    Ok(())
}

Then call the reducer after publishing:

spacetime build
spacetime publish my-game
spacetime call my-game load_map

Why This Exists

SpacetimeDB modules run in WASM sandboxes with no filesystem access. You can't just std::fs::read_to_string("map.tmx") in a reducer - it'll fail with "operation not supported on this platform".

This library provides two solutions:

load_tmx_map_from_str() - Parses TMX XML in-memory using quick-xml. Works in WASM. Use this.
load_tmx_map() - Uses the tiled crate's file loader. Doesn't work in WASM. Only useful for testing outside SpacetimeDB.

What Gets Stored

The library defines six tables:

tiled_map - Map dimensions, tile size, orientation
tiled_layer - Layer names, types, visibility, opacity
tiled_tile - Individual tiles with position, GID, and flip flags
tiled_tileset - Tileset metadata (names, dimensions, tile counts)
tiled_object - Objects from object layers (positions, sizes, shapes)
tiled_property - Custom properties on any element

All tables are indexed for querying by map_id or layer_id.

Usage Patterns

Server-Side Map Loading

Option 1: Embedded maps (recommended)

#[reducer]
pub fn init(ctx: &ReducerContext) -> Result<(), String> {
    const OVERWORLD: &str = include_str!("../maps/overworld.tmx");
    const DUNGEON: &str = include_str!("../maps/dungeon.tmx");

    load_tmx_map_from_str(ctx, "overworld", OVERWORLD)?;
    load_tmx_map_from_str(ctx, "dungeon", DUNGEON)?;
    Ok(())
}

Option 2: Client-uploaded maps

#[reducer]
pub fn upload_map(ctx: &ReducerContext, name: String, tmx: String) -> Result<(), String> {
    load_tmx_map_from_str(ctx, &name, &tmx)?;
    Ok(())
}

Then from your client: spacetime call my-game upload_map '{"name": "custom", "tmx": "<?xml version..."}'

Querying Map Data

use spacetimedb::{reducer, ReducerContext, Table};

#[reducer]
pub fn check_collision(ctx: &ReducerContext, x: u32, y: u32) -> Result<bool, String> {
    // Get collision layer (assuming it's layer 1)
    let tile = ctx.db.tiled_tile()
        .iter()
        .find(|t| t.layer_id == 1 && t.x == x && t.y == y);

    // Non-zero GID = collision tile
    Ok(tile.map_or(false, |t| t.gid != 0))
}

#[reducer]
pub fn get_spawn_points(ctx: &ReducerContext) -> Result<(), String> {
    let spawns: Vec<_> = ctx.db.tiled_object()
        .iter()
        .filter(|obj| obj.obj_type == "spawn")
        .collect();

    for spawn in spawns {
        log::info!("Spawn at ({}, {}): {}", spawn.x, spawn.y, spawn.name);
    }
    Ok(())
}

Client Setup

The Rust client SDK requires an event loop to process messages. Without it, subscriptions never apply and you won't get any data.

use spacetimedb_sdk::{DbContext, Table};
use module_bindings::*;

fn main() {
    let conn = DbConnection::builder()
        .with_uri("http://localhost:3000")
        .with_module_name("my-game")
        .build()
        .unwrap();

    conn.subscription_builder()
        .on_applied(on_sub_applied)
        .subscribe([
            "SELECT * FROM tiled_map",
            "SELECT * FROM tiled_layer",
            "SELECT * FROM tiled_tile",
        ]);

    // THIS IS REQUIRED - starts processing messages
    conn.run_threaded();

    // Wait a moment for subscription to apply
    std::thread::sleep(Duration::from_millis(500));

    // Now you can query data
    let maps: Vec<_> = conn.db.tiled_map().iter().collect();
    println!("Loaded {} maps", maps.len());
}

fn on_sub_applied(ctx: &module_bindings::SubscriptionEventContext) {
    println!("Subscription applied!");
    // Initial data is available here
}

Important: You must import the table accessor traits:

use module_bindings::{
    tiled_map_table::TiledMapTableAccess,
    tiled_layer_table::TiledLayerTableAccess,
    tiled_tile_table::TiledTileTableAccess,
    // ... etc
};

Examples

Check out examples/simple_game/ for a complete working example with:

Server module that loads an embedded demo map
Interactive Rust client that queries map data
Sample TMX file with layers, tiles, and objects

To run it:

cd examples/simple_game/server
spacetime build
spacetime publish simple-game
spacetime call simple-game load_demo_map

cd ../client
spacetime generate --lang rust --out-dir src/module_bindings --project-path ../server
cargo run

Common Issues

"No maps loaded" in client

You forgot to call conn.run_threaded(). The SDK doesn't process messages automatically - you have to start an event loop.

"operation not supported on this platform"

You're trying to use load_tmx_map() in a WASM module. Use load_tmx_map_from_str() instead with include_str!().

"unresolved import" or "method not found" errors in client

Missing trait imports. The generated bindings define traits like TiledMapTableAccess that you need to import to use .tiled_map() methods.

use module_bindings::tiled_map_table::TiledMapTableAccess;

Build fails with "clang: program not found"

The zstd-sys dependency needs LLVM/clang for WASM compilation. Install LLVM and add it to your PATH, or use WSL/Linux.

Supported Tiled Features

✅ Orthogonal, isometric, staggered, and hexagonal maps
✅ Tile layers (finite and infinite)
✅ Object layers with rectangles, ellipses, and points
✅ Custom properties (string, int, float, bool, color, file)
✅ Tile flipping (horizontal, vertical, diagonal)
✅ Multiple tilesets per map
✅ CSV tile data encoding
❌ Base64/gzip tile encoding (not yet)
❌ Polygon/polyline vertices (shape type only)
❌ Tile animations
❌ Wang sets

License

Licensed under either of:

Apache License, Version 2.0 (LICENSE-APACHE)
MIT license (LICENSE-MIT)

at your option.

Contributing

Contributions are welcome! See CONTRIBUTING.md for guidelines.

Areas that need help:

Base64/gzip tile encoding support
Polygon/polyline vertex storage
Tile animation support
More examples

spacetime_tiled 0.1.0