openclaw-coder-workspace/MEMORY.md

MEMORY.md — Durable Facts & Decisions

Godot 4.7 — Stage 2 TileMapLayer collision (verified in headless)

• TileSet + TileMapLayer + polygon collision WORK in Godot 4.7 headless. Verified: Fox drops onto a TileMapLayer tile and lands at the tile's polygon top edge (steps=13, vel.y=0, on_floor=true).
• Headless physics pattern: run via flatpak run org.godotengine.Godot --headless --path . with run/main_scene set to a scene whose root is a Node2D script with _ready() + _physics_process(delta). The engine's main loop drives physics (no need for PhysicsServer2D.step() / integrate_forces).
• Two headless gotchas for TileMapLayer:
  1. The moving body (Fox) must be a direct child of the root Node2D, NOT nested inside the TileMapLayer. A Fox nested inside TileMapLayer gets a null physics space (body->get_space() null → move_and_slide no-ops) and falls forever.
  2. Fox must start above the tile polygon. TileSet polygon points are in tile-local coords with the tile's top edge at y=0 and downward positive. If Fox starts below y=32 it's already past the tile and falls away. Start at negative y.
• Per-tile collision polygon API (Godot 4.7):
  • TileSet.add_physics_layer() (void, auto-indexed), set_physics_layer_collision_layer(idx, mask), set_physics_layer_collision_mask(idx, mask).
  • TileMapLayer.get_cell_tile_data(Vector2i coords) → TileData object (returns a live/mutable ref; edits persist — verified re-read = 1).
  • td.set_collision_polygons_count(layer_index, count), td.set_collision_polygon_points(layer_index, polygon_index, PackedVector2Array([...])).
  • get_cell_tile_data is the correct accessor; there is NO set_tile_data on the atlas source and no TileSetCollisionObject2D.
• add_child is on Node (not World2D); get_root() returns a Window, not Node2D. Use a Node2D script as scene root for physics.