# SpriteNode Class Layout

## Purpose

This note captures the current class-level read of the `SpriteNode` family so later Ghidra class work can move quickly and conservatively.

Compared with `EntityDispatchEntry`, this family has a cleaner explicit virtual/event-dispatch surface and a more bounded ownership model. That makes it an excellent second pilot for class lifting.

## Current Best Class-Level Read

`SpriteNode` is a tree-based render/UI node family with:

- child-chain ownership
- accumulated position and bounds propagation
- dirty-state tracking
- central event dispatch through a small virtual surface
- destructor ownership over child nodes and global focus state

This already looks much closer to an ordinary C++ object family than many gameplay-side structures.

## Strongest Evidence Anchors

### Destructor

#### `000b:326e` `sprite_node_destroy`

Current best read:

- destructor-style path
- sets vtable ptr to `0x501a`
- clears global focus pointer `[0x4fd0:0x4fd2]` if `self`
- releases child nodes
- frees object memory through `mem_free`

This is the strongest current single proof that `SpriteNode` should be lifted as an owned object family.

### Event dispatch

#### `000b:3ab2` `sprite_node_dispatch_event`

Current best read:

- large event dispatch switch
- checks event types `2/4/8/0x100`
- updates global focus pointer at `[0x4fd0:0x4fd2]`
- dispatches through virtual slots `+0x14`, `+0x18`, `+0x20`, `+0x24`

This is the strongest current proof of a stable virtual method surface.

### Dirty/update family

- `000b:3380 sprite_node_is_dirty`
- `000b:33a6 sprite_node_mark_dirty`
- `000b:40ee sprite_node_update_and_dispatch`

These show that node state changes and redraw/update dispatch are methods on the same family, not just free helper functions wandering across unrelated data.

### Recursive tree helpers

- `000a:b988 sprite_node_get_or_traverse`
- `000b:358d sprite_tree_accumulate_pos`
- `000b:3a00 sprite_tree_sum_x_offset`
- `000b:3a35 sprite_tree_sum_y_offset`

These are strong evidence for a child-linked tree object with inherited coordinate accumulation.

## Candidate Layout

This layout is intentionally conservative.

| Offset | Current name | Confidence | Current meaning |
|---|---|---|---|
| `+0x19/+0x1b` | `child_or_next_ptr` | High | Child-chain pointer pair used by recursive traversal and offset accumulation. |
| `+0x21` | `local_x_offset` | High | Summed by `sprite_tree_sum_x_offset` / accumulate helpers. |
| `+0x23` | `local_y_offset` | High | Summed by `sprite_tree_sum_y_offset` / accumulate helpers. |
| `+0x29` | `dirty_flags` | High | Checked by `sprite_node_is_dirty`; manipulated by mark/update paths. |
| `+0x17e` | `redraw_flag` | Medium | Cleared by `sprite_clear_redraw_flag`; likely a subtype or larger-object field tied to one SpriteNode family variant. |

## Layout Caveat

The current notes likely mix a compact core `SpriteNode` with one or more larger derived UI/display objects. The evidence for `+0x17e` strongly suggests there are bigger family members or wrapper objects in the same virtual ecosystem.

So the safe future modeling strategy is:

- define a small `SpriteNodeBase`
- keep larger UI/display fields in derived or sibling structs until more offsets are closed

## Candidate Method Map

### Strong instance methods

| Address | Current function | Candidate method role |
|---|---|---|
| `000b:326e` | `sprite_node_destroy` | `Destroy()` |
| `000b:3380` | `sprite_node_is_dirty` | `IsDirty()` |
| `000b:33a6` | `sprite_node_mark_dirty` | `MarkDirty()` |
| `000b:3ab2` | `sprite_node_dispatch_event` | `DispatchEvent()` |
| `000b:40ee` | `sprite_node_update_and_dispatch` | `UpdateAndDispatch()` |
| `000a:b988` | `sprite_node_get_or_traverse` | `GetOrTraverse()` |

### Strong family-local helpers that may remain free/static

| Address | Current function | Why it may stay non-method |
|---|---|---|
| `000b:3a00` | `sprite_tree_sum_x_offset` | Pure recursive accumulation helper; method status depends on later decompile readability. |
| `000b:3a35` | `sprite_tree_sum_y_offset` | Same as above. |
| `000b:330c` | `sprite_tree_dispatch_wrapper` | Looks like a pure thunk wrapper rather than a meaningful source-level method. |
| `000b:3362` | `sprite_tree_unwind_check` | Stack-segment guard helper; probably not worth presenting as a class method. |

## Candidate Virtual Slot Map

The currently verified slots are already good enough for a first typed vtable.

| Slot offset | Current best role | Evidence |
|---|---|---|
| `+0x14` | event handler A | `sprite_node_dispatch_event` dispatches here for one event class |
| `+0x18` | event handler B | same dispatcher |
| `+0x20` | event handler C | same dispatcher |
| `+0x24` | event handler D | same dispatcher |

The seg091 default-slot helpers are also useful evidence:

- `000a:7b44`, `000a:7b49`, `000a:7b53`, `000a:7b4e`, `000a:7b78`, `000a:7b7d`, `000a:7b30`, `000a:7b3f`, `000a:7b35`, `000a:7b3a`
- `000a:7b58` returns zero and behaves like a default no-op boolean slot
- `000a:7b5f` is a forwarding trampoline slot

These likely belong to one or more shared/default node vtables and should be preserved as vtable evidence even if they never become pretty source-level methods.

## Ownership And Global State

### Focus/global state

Global focus pointer `[0x4fd0:0x4fd2]` is updated in the dispatch family and cleared in the destructor.

That gives the family a real interaction with global UI focus/state, but the key point for class work is simpler:

- focus ownership is tied to the node family itself
- this is not just an arbitrary free helper changing global UI state

### Child ownership

The destructor and recursive sum/traverse helpers strongly suggest real child ownership or at least managed child linkage.

That means later class modeling should preserve a node/tree mental model rather than flattening everything into stand-alone display items.

## Candidate Ghidra Modeling Plan

When class authoring begins, the safest sequence for this family is:

1. create class namespace `SpriteNode`
2. move `Destroy`, `IsDirty`, `MarkDirty`, `DispatchEvent`, `UpdateAndDispatch`, and `GetOrTraverse` first
3. create minimal `SpriteNodeBase` struct with the stable offsets around `+0x19`, `+0x21`, `+0x23`, and `+0x29`
4. create provisional vtable with slots `+0x14`, `+0x18`, `+0x20`, `+0x24`
5. keep recursive tree helpers outside the class until decompiler output shows they benefit from becoming methods

## Open Questions

- exact root vtable address or addresses for the main SpriteNode family
- whether the `+0x17e` redraw flag belongs to a derived display node rather than the compact base node
- which event-code cases map to which slot semantically beyond the current `A/B/C/D` placeholder naming
- whether `sprite_tree_accumulate_pos` should become a class method, a static helper, or a separate geometry utility

## Immediate Follow-Up Value

The most useful next companion work after this note is not more sprite detail by itself. It is the rebuild-ABI note, because once the first few class families are documented this well, the next real risk is drifting away from the original memory and calling-convention model before any code is emitted.