Pathfinding and re-pickup of the project

shared/src/lib.rs

@@ -32,6 +32,18 @@ pub fn chunk_coords(id: u32) -> (i16, i16) {
     (id as u16 as i16, (id >> 16) as u16 as i16)
 }
 
+/// Shared movement vocabulary: whether a tile id blocks movement.
+///
+/// Single source of truth for both the server (collision in the sim) and the client
+/// (movement prediction). Keep this in lockstep with the tileset in `overworld.tga`.
+/// Currently every authored tile is walkable.
+pub fn tile_collidable(tile_id: u16) -> bool {
+    match tile_id {
+        // e.g. 146 => true,  // trees / rocks
+        _ => false,
+    }
+}
+
 #[derive(Clone, Copy, Pod, Zeroable)]
 #[repr(C, packed)]
 pub struct Header {