Godot 4, from the code that shipped

Write-ups on the systems behind the SELOdev Godot tools. Each post is drawn from a working system and leaves you able to build a rough version yourself.

• Migrating old Godot save data when your schema changes: A versioned Godot 4 save format with forward schema migration: read the version field, walk an old file one hop at a time to the current shape, refuse what you cannot upgrade.
• Stat modifiers from gear in Godot 4: How equipping gear applies stat modifiers in Godot 4 and unequipping removes them cleanly, and why you recompute totals from worn gear instead of adding and subtracting deltas.
• Building a paper doll equipment system in Godot 4: Build a paper doll equipment system in Godot 4: named slots that accept only matching gear, and the displaced item returning to your bag on every swap.
• Item stacking and splitting a stack in Godot 4: How item stacking works in a Godot 4 inventory, then how to build a right-click split-stack on top of add_item and remove_item without ever losing an item.
• Drag and drop inventory UI in Godot 4: Godot 4 hands you three drag-and-drop callbacks and no opinion about what a drop means. Here is how to build inventory slots on top of a real stacking inventory, where a partial merge and a clean rejection both fall out of one method call, and the item never mutates behind your back.