Library for server-side collisions, physics world simulation, tilemap pathfinding, and Tiled TMX parsing.

Main features

• TMX parsing — load Tiled maps (tile layers, objectgroup, tilesets)
• Collision world — static and dynamic bodies (AABB), intersection checks and step simulation
• Pathfinding — A* over tilemap with TileSource protocol support
• TMX → World integration — build collision world from map layers (Walls, objectgroup)

Server loop

World.step(world, dt) is called every server tick (e.g. 60 times per second). Use a fixed dt = 1/60 for determinism or the actual interval between ticks.

Example

# Parse TMX
map = ExCollision.TMX.Parser.parse!("data/Dun.tmx")

# Collision world from map ("Walls" layer and objectgroup)
world = ExCollision.TMX.WorldBuilder.from_tmx(map, collision_layer: "Walls")

# Pathfinding over layer (walkability: GID=0). In Dun.tmx lines 18–28 are all zeros
layer = ExCollision.TMX.Map.layer_by_name(map, "Floor")
source = ExCollision.TMX.TileLayerTileSource.new(layer)
{:ok, path} = ExCollision.Pathfinding.AStar.find_path(source, {5, 20}, {30, 25})

# Player — Body. Every server tick: step(world, 1/60)
{world, player_id} = ExCollision.World.add_body(world, ExCollision.World.Body.from_xywh(:player, 50, 50, 16, 16, velocity: {0, 0}))
{:ok, world} = ExCollision.World.set_velocity(world, player_id, 32, 0)
world = ExCollision.World.step(world, 1/60)  # every server tick

# Interpolation for smooth rendering (alpha = time since last step / step interval)
{:ok, {x, y}} = ExCollision.World.get_interpolated_position(world, player_id, 0.5)
# Optional: clamp alpha to [0, 1]: get_interpolated_position(..., clamp: true) or get_interpolated_position_clamped/3