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# Godot 4 editor cache/import directory
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.godot/
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@@ -0,0 +1,462 @@
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# Avatar Component System & glTF Attachment Spec
|
||||
|
||||
> **Status:** Proposed
|
||||
> **Owner:** Platform team
|
||||
> **Related:** Server authority + client prediction, world chunk data format
|
||||
|
||||
## 1. Overview
|
||||
|
||||
This document specifies the **avatar component system** for **agp-game**, a
|
||||
Godot-based multiplayer game. It defines:
|
||||
|
||||
- How an avatar is decomposed into **body parts** and **attachment slots**.
|
||||
- How **cosmetic attachments** (clothing, accessories, gear) mount onto the
|
||||
base body.
|
||||
- The **glTF/GLB format requirements** that all avatar assets must satisfy so
|
||||
they can be loaded, skinned, and networked consistently.
|
||||
|
||||
The goal is a **modular, data-driven avatar pipeline**: a single base body rig
|
||||
plus swappable attachments, all authored in glTF and consumed by a shared Godot
|
||||
runtime. This enables player customization, cosmetic monetization, and
|
||||
server-authoritative validation of what a player is wearing.
|
||||
|
||||
### 1.1 Design Goals
|
||||
|
||||
- **Modularity:** Body parts and attachments are independent assets that can be
|
||||
combined at runtime without re-exporting.
|
||||
- **Consistency:** A single, well-defined skeleton and slot convention so any
|
||||
attachment fits any base body.
|
||||
- **Networkability:** The avatar's composition is expressed as a compact,
|
||||
serializable **loadout** that the server can validate and replicate.
|
||||
- **Performance:** Attachments are skinned to the same skeleton and share
|
||||
materials where possible to minimize draw calls and skinning cost.
|
||||
- **Tooling-friendly:** Assets are authored in standard glTF 2.0 and validated
|
||||
by a build-time checker.
|
||||
|
||||
---
|
||||
|
||||
## 2. Avatar Decomposition
|
||||
|
||||
### 2.1 The Base Body
|
||||
|
||||
Every avatar is built on a **base body** — a single glTF asset containing:
|
||||
|
||||
- A **skeleton** (the canonical rig, see §3).
|
||||
- A **base mesh** for the skin/body (head, torso, arms, legs).
|
||||
- **Attachment points** (empty nodes) that define where accessories mount.
|
||||
|
||||
The base body is the only asset that carries the skeleton. Attachments reference
|
||||
the skeleton by **bone name** and are skinned to it; they never carry their own
|
||||
rig.
|
||||
|
||||
### 2.2 Body Parts vs. Attachments
|
||||
|
||||
Two distinct concepts:
|
||||
|
||||
| Concept | Definition | Example |
|
||||
|----------------|-------------------------------------------------------------------------|----------------------------------|
|
||||
| **Body part** | A mesh that replaces part of the base body's skin (e.g., a different head, a tail, wings). | Alternate head, cybernetic arm |
|
||||
| **Attachment** | A mesh that mounts *on top of* the body without replacing it (clothing, accessories). | Shirt, hat, glasses, backpack |
|
||||
|
||||
The distinction matters for **slot exclusivity** and **layering**:
|
||||
|
||||
- **Body parts** are *exclusive* per slot — only one head can be equipped.
|
||||
- **Attachments** are *layered* — a hat and glasses can coexist, and both sit
|
||||
above the head mesh.
|
||||
|
||||
---
|
||||
|
||||
## 3. Skeleton & Slot Convention
|
||||
|
||||
### 3.1 Canonical Skeleton
|
||||
|
||||
All avatars share a **canonical skeleton** with a fixed set of bone names. This
|
||||
is the contract that lets any attachment fit any body. The skeleton follows a
|
||||
humanoid convention (Godot's `Humanoid` profile / glTF VRM-style naming).
|
||||
|
||||
Required bones (subset of the full rig):
|
||||
|
||||
```
|
||||
Root
|
||||
├── Hips
|
||||
│ ├── Spine
|
||||
│ │ ├── Chest
|
||||
│ │ │ ├── Neck
|
||||
│ │ │ │ └── Head
|
||||
│ │ │ │ ├── HeadTop # hat / hair mount
|
||||
│ │ │ │ ├── Jaw # face accessories
|
||||
│ │ │ │ └── LeftEye / RightEye
|
||||
│ │ │ ├── LeftShoulder
|
||||
│ │ │ │ └── LeftUpperArm
|
||||
│ │ │ │ └── LeftLowerArm
|
||||
│ │ │ │ └── LeftHand
|
||||
│ │ │ └── RightShoulder
|
||||
│ │ │ └── RightUpperArm
|
||||
│ │ │ └── RightLowerArm
|
||||
│ │ │ └── RightHand
|
||||
│ │ └── (Chest children for torso attachments)
|
||||
│ ├── LeftUpperLeg
|
||||
│ │ └── LeftLowerLeg
|
||||
│ │ └── LeftFoot
|
||||
│ └── RightUpperLeg
|
||||
│ └── RightLowerLeg
|
||||
│ └── RightFoot
|
||||
```
|
||||
|
||||
**Rules:**
|
||||
|
||||
- Bone names are **case-sensitive** and must match exactly.
|
||||
- The skeleton is **T-pose** at rest for consistent skinning.
|
||||
- Attachments must be skinned to **at least** the bones they deform; static
|
||||
accessories may be parented to a single bone (e.g., a hat parented to `Head`).
|
||||
|
||||
### 3.2 Attachment Slots
|
||||
|
||||
Slots are the **logical mount points** for body parts and attachments. Each slot
|
||||
maps to one or more bones and defines what can be equipped there.
|
||||
|
||||
| Slot ID | Category | Mount bone(s) | Exclusivity | Example assets |
|
||||
|----------------|--------------|--------------------|-------------|-------------------------------|
|
||||
| `head` | body part | `Head` | exclusive | alternate head, face |
|
||||
| `hair` | attachment | `HeadTop` | exclusive | hairstyles, hats |
|
||||
| `face` | attachment | `Jaw` | exclusive | glasses, masks, beards |
|
||||
| `torso` | body part | `Chest` | exclusive | alternate torso |
|
||||
| `chest` | attachment | `Chest` | exclusive | shirts, armor, chest gear |
|
||||
| `back` | attachment | `Chest` (back) | exclusive | backpacks, wings, capes |
|
||||
| `left_arm` | body part | `LeftUpperArm` | exclusive | alternate arm |
|
||||
| `right_arm` | body part | `RightUpperArm` | exclusive | alternate arm |
|
||||
| `left_hand` | attachment | `LeftHand` | exclusive | gloves, weapons (held) |
|
||||
| `right_hand` | attachment | `RightHand` | exclusive | gloves, weapons (held) |
|
||||
| `legs` | body part | `Hips` | exclusive | alternate legs |
|
||||
| `pants` | attachment | `Hips` | exclusive | pants, skirts |
|
||||
| `left_foot` | attachment | `LeftFoot` | exclusive | shoes |
|
||||
| `right_foot` | attachment | `RightFoot` | exclusive | shoes |
|
||||
| `accessory` | attachment | `Root` (free) | multiple | belts, jewelry, floating items|
|
||||
|
||||
**Slot semantics:**
|
||||
|
||||
- **`exclusive`** slots allow at most one equipped item at a time.
|
||||
- The **`accessory`** slot is *multi-slot* — multiple accessories may be equipped
|
||||
simultaneously (bounded by a configurable limit, e.g., 8).
|
||||
- **Body-part slots** (`head`, `torso`, `legs`, `left_arm`, `right_arm`) replace
|
||||
the corresponding base mesh. When a body part is equipped, the base mesh for
|
||||
that region is hidden.
|
||||
- **Attachment slots** layer on top of the base mesh and never hide it.
|
||||
|
||||
### 3.3 Slot → Bone Mapping
|
||||
|
||||
Each slot declares a **primary mount bone** and an optional **secondary bone
|
||||
list** for skinning. The runtime uses this to:
|
||||
|
||||
1. Parent static accessories to the mount bone.
|
||||
2. Skin skinned attachments to the union of the slot's bones.
|
||||
|
||||
---
|
||||
|
||||
## 4. glTF/GLB Format Requirements
|
||||
|
||||
All avatar assets (base bodies, body parts, attachments) are distributed as
|
||||
**glTF 2.0** (`.gltf` + external buffers/textures) or **GLB** (`.glb`, binary
|
||||
container). GLB is the preferred distribution format for runtime loading.
|
||||
|
||||
### 4.1 Required Conventions
|
||||
|
||||
| Concern | Requirement |
|
||||
|--------------------|------------------------------------------------------------------------------|
|
||||
| **Format** | glTF 2.0 (`.gltf` or `.glb`). GLB preferred for runtime. |
|
||||
| **Coordinate system** | glTF standard: **+Y up, +Z forward, right-handed**. Godot converts to its own convention on import. |
|
||||
| **Units** | Meters. Avatar height ~1.8 m at the `Root` bone. |
|
||||
| **Skeleton** | Single skeleton per asset; bone names per §3.1. |
|
||||
| **Skinning** | `skins` + `nodes` with `JOINTS_0` / `WEIGHTS_0` accessors. |
|
||||
| **Pose** | T-pose at rest. |
|
||||
| **Materials** | PBR metallic-roughness. Use `KHR_materials_unlit` for emissive/UI-only items. |
|
||||
| **Textures** | Max 2048×2048; power-of-two preferred. Use `KHR_texture_basisu` (BasisU) for runtime. |
|
||||
| **Animation** | Optional. If present, must not rename or remove canonical bones. |
|
||||
|
||||
### 4.2 Asset Metadata (extras)
|
||||
|
||||
Each asset **must** declare its slot and identity in the glTF `asset.extras`
|
||||
object. This is the machine-readable contract consumed by the build pipeline and
|
||||
runtime.
|
||||
|
||||
```json
|
||||
{
|
||||
"asset": {
|
||||
"version": "2.0",
|
||||
"extras": {
|
||||
"agp": {
|
||||
"type": "attachment", // "base_body" | "body_part" | "attachment"
|
||||
"slot": "chest", // slot ID from §3.2
|
||||
"id": "shirt_bandit_01", // globally unique asset id
|
||||
"display_name": "Bandit Shirt",
|
||||
"version": "1.0.0",
|
||||
"mount_bone": "Chest", // primary mount bone
|
||||
"skin_bones": ["Chest", "Spine", "LeftUpperArm", "RightUpperArm"],
|
||||
"exclusive": true, // matches slot exclusivity
|
||||
"tags": ["cloth", "common"],
|
||||
"author": "platform-team"
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
**Validation rules for `extras.agp`:**
|
||||
|
||||
- `type` must be one of `base_body`, `body_part`, `attachment`.
|
||||
- `slot` must be a known slot ID (§3.2).
|
||||
- `mount_bone` must exist in the canonical skeleton.
|
||||
- `skin_bones` must all exist in the canonical skeleton.
|
||||
- `exclusive` must match the slot's declared exclusivity.
|
||||
- `id` must be unique across the asset catalog.
|
||||
|
||||
### 4.3 Node Naming Convention
|
||||
|
||||
To make assets self-describing and mergeable, nodes follow a convention:
|
||||
|
||||
- **Base body:** the mesh node is named `Body`; the skeleton root is `Root`.
|
||||
- **Body part:** the mesh node is named `<SlotID>_Mesh` (e.g., `head_Mesh`).
|
||||
- **Attachment:** the mesh node is named `<SlotID>_<AssetID>` (e.g.,
|
||||
`chest_shirt_bandit_01`).
|
||||
- **Attachment points** (empty nodes) on the base body are named
|
||||
`attach_<slot>` (e.g., `attach_head`, `attach_left_hand`).
|
||||
|
||||
### 4.4 Material & Texture Requirements
|
||||
|
||||
- All materials use the **metallic-roughness** PBR model.
|
||||
- Textures are embedded in the GLB or referenced as external files; external
|
||||
references must be relative paths within the asset package.
|
||||
- **Color customization** is supported via a `baseColorFactor` tint applied at
|
||||
runtime (multiplied over the albedo). Assets should use a neutral albedo
|
||||
(white/gray) where tinting is intended.
|
||||
- **Masked/transparent** materials must set the correct alpha mode
|
||||
(`MASK` or `BLEND`) and `alphaCutoff`.
|
||||
|
||||
### 4.5 Skeleton Merging at Runtime
|
||||
|
||||
When an attachment is loaded, the runtime **merges** it onto the base body:
|
||||
|
||||
1. Load the base body (skeleton + base meshes).
|
||||
2. Load each equipped attachment.
|
||||
3. For each attachment, **re-target its skin** to the base body's skeleton by
|
||||
bone name (no re-export needed).
|
||||
4. Parent static accessories to their `mount_bone`.
|
||||
5. Hide base meshes for any equipped body-part slots.
|
||||
6. Apply material tints and merge into the render tree.
|
||||
|
||||
The merge is **name-based** — bone names must match exactly (§3.1). This is the
|
||||
core reason for the strict naming contract.
|
||||
|
||||
---
|
||||
|
||||
## 5. Loadout Model (Network & Persistence)
|
||||
|
||||
The avatar's composition is serialized as a **loadout** — a compact, ordered
|
||||
list of equipped asset IDs. This is what the server validates, persists, and
|
||||
replicates.
|
||||
|
||||
### 5.1 Loadout JSON
|
||||
|
||||
```json
|
||||
{
|
||||
"base_body": "base_human_male_01",
|
||||
"slots": {
|
||||
"head": "head_cyber_01",
|
||||
"hair": "hair_mohawk_01",
|
||||
"face": null,
|
||||
"torso": null,
|
||||
"chest": "chest_bandit_01",
|
||||
"back": "backpack_01",
|
||||
"left_arm": null,
|
||||
"right_arm": null,
|
||||
"left_hand": "glove_leather_01",
|
||||
"right_hand": "glove_leather_01",
|
||||
"legs": null,
|
||||
"pants": "pants_cargo_01",
|
||||
"left_foot": "shoe_boot_01",
|
||||
"right_foot": "shoe_boot_01",
|
||||
"accessory": ["belt_01", "necklace_01"]
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
**Rules:**
|
||||
|
||||
- `base_body` is required and must reference a valid `base_body` asset.
|
||||
- Each exclusive slot holds **at most one** asset id (or `null`).
|
||||
- `accessory` is an array (0..N, bounded).
|
||||
- The server validates that every id exists in the catalog and that slot
|
||||
exclusivity is respected.
|
||||
|
||||
### 5.2 Network Replication
|
||||
|
||||
The loadout is replicated as part of the player's spawn/state data:
|
||||
|
||||
```
|
||||
spawn_entity:
|
||||
entity_id: uint32
|
||||
type: player
|
||||
transform: { x, y, rot }
|
||||
props:
|
||||
loadout_hash: uint32 # hash of the loadout for change detection
|
||||
loadout: { ... } # full loadout on spawn / on change
|
||||
```
|
||||
|
||||
- The **full loadout** is sent on spawn and whenever it changes (reliable).
|
||||
- A **`loadout_hash`** lets clients skip re-resolving assets if unchanged.
|
||||
- The server is the **authority** on the loadout; clients send *requests* to
|
||||
change equipment, and the server validates and broadcasts the result.
|
||||
|
||||
### 5.3 Server-Side Validation
|
||||
|
||||
The server rejects a loadout if:
|
||||
|
||||
- `base_body` is missing or unknown.
|
||||
- Any slot references an unknown asset id.
|
||||
- An exclusive slot has more than one item.
|
||||
- An asset's declared `slot` does not match the slot it is placed in.
|
||||
- The accessory list exceeds the configured limit.
|
||||
- The asset is not owned/unlocked by the player (for gated cosmetics).
|
||||
|
||||
---
|
||||
|
||||
## 6. Godot Runtime Architecture
|
||||
|
||||
### 6.1 Node Structure
|
||||
|
||||
```
|
||||
Avatar (Node3D)
|
||||
├── Skeleton3D # canonical skeleton (from base body)
|
||||
├── BodyMeshes # base body meshes (skinned to Skeleton3D)
|
||||
│ ├── head_Mesh
|
||||
│ ├── torso_Mesh
|
||||
│ └── ...
|
||||
├── Attachments # equipped attachments
|
||||
│ ├── chest_shirt_bandit_01
|
||||
│ ├── hair_mohawk_01
|
||||
│ └── ...
|
||||
└── AttachmentPoints # empty nodes for dynamic mounting
|
||||
├── attach_head
|
||||
├── attach_left_hand
|
||||
└── ...
|
||||
```
|
||||
|
||||
### 6.2 Core Classes
|
||||
|
||||
| Class | Responsibility |
|
||||
|--------------------------|-------------------------------------------------------------|
|
||||
| `AvatarSystem` | Loads base body + attachments, resolves loadouts, owns the avatar node. |
|
||||
| `AvatarLoader` | glTF/GLB import, skeleton merge, skin re-targeting. |
|
||||
| `AvatarSlotRegistry` | Static registry of slot definitions (id, bones, exclusivity).|
|
||||
| `AvatarLoadout` | Serializable loadout model + validation. |
|
||||
| `AvatarCatalog` | Asset catalog (id → asset metadata + resource path). |
|
||||
| `AvatarVisualizer` | Builds the render tree from a loadout. |
|
||||
|
||||
### 6.3 Loading Pipeline
|
||||
|
||||
```
|
||||
loadout JSON
|
||||
│
|
||||
▼
|
||||
AvatarCatalog.resolve(loadout) # id → asset metadata + GLB path
|
||||
│
|
||||
▼
|
||||
AvatarLoader.load_base_body() # import GLB, extract skeleton + base meshes
|
||||
│
|
||||
▼
|
||||
for each equipped slot:
|
||||
AvatarLoader.load_attachment()# import GLB, re-target skin to skeleton
|
||||
│
|
||||
▼
|
||||
AvatarVisualizer.assemble() # parent, hide replaced parts, apply tints
|
||||
│
|
||||
▼
|
||||
Avatar node ready for render
|
||||
```
|
||||
|
||||
### 6.4 Performance Considerations
|
||||
|
||||
- **Shared skeleton:** All meshes skin to one `Skeleton3D`, so skinning is
|
||||
computed once per frame.
|
||||
- **Material batching:** Attachments that share a material are merged into a
|
||||
single mesh where possible (static accessories).
|
||||
- **LOD:** Optional LOD variants per asset; the runtime selects based on
|
||||
distance.
|
||||
- **Caching:** Resolved loadouts and imported GLB resources are cached by
|
||||
`AvatarCatalog` to avoid re-importing on respawn or re-join.
|
||||
|
||||
---
|
||||
|
||||
## 7. Asset Pipeline & Validation
|
||||
|
||||
### 7.1 Build-Time Validation
|
||||
|
||||
A build-time checker validates every asset before it enters the catalog:
|
||||
|
||||
1. **Format check:** valid glTF 2.0 / GLB.
|
||||
2. **Metadata check:** `extras.agp` present and valid (§4.2).
|
||||
3. **Skeleton check:** all `skin_bones` exist in the canonical skeleton.
|
||||
4. **Slot check:** `slot` is known and `exclusive` matches.
|
||||
5. **Mesh check:** meshes are skinned (or static accessories parented to a bone).
|
||||
6. **Texture check:** sizes, formats, and alpha modes are valid.
|
||||
7. **Uniqueness check:** `id` is unique.
|
||||
|
||||
### 7.2 Catalog Manifest
|
||||
|
||||
The catalog is a JSON manifest mapping asset ids to metadata and resource paths:
|
||||
|
||||
```json
|
||||
{
|
||||
"assets": {
|
||||
"base_human_male_01": {
|
||||
"type": "base_body",
|
||||
"path": "res://assets/avatars/base_human_male_01.glb",
|
||||
"version": "1.0.0"
|
||||
},
|
||||
"chest_bandit_01": {
|
||||
"type": "attachment",
|
||||
"slot": "chest",
|
||||
"path": "res://assets/avatars/chest_bandit_01.glb",
|
||||
"version": "1.0.0"
|
||||
}
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 8. Security & Anti-Cheat
|
||||
|
||||
- **Server-authoritative loadouts:** Clients only *request* equipment changes;
|
||||
the server validates against the catalog and the player's owned items.
|
||||
- **No client asset injection:** Clients cannot send arbitrary GLB data; they
|
||||
reference catalog ids only.
|
||||
- **Rate limiting:** Equipment-change requests are rate-limited per peer.
|
||||
- **Hash verification:** The `loadout_hash` lets the server detect tampered or
|
||||
stale loadout state.
|
||||
|
||||
---
|
||||
|
||||
## 9. Open Questions / Future Work
|
||||
|
||||
- **Morph targets / blendshapes:** Support for facial expressions and body
|
||||
morphs (e.g., height, muscle) via glTF morph targets.
|
||||
- **Physics attachments:** Cloth simulation for capes/skirts (Godot cloth).
|
||||
- **Dynamic tinting UI:** A color-picker that writes `baseColorFactor` tints.
|
||||
- **VRM compatibility:** Consider supporting VRM (a glTF extension for
|
||||
humanoid avatars) as an import source.
|
||||
- **Attachment LOD streaming:** Streaming high-res attachments on demand.
|
||||
|
||||
---
|
||||
|
||||
## 10. Summary
|
||||
|
||||
| Concern | Decision |
|
||||
|------------------------|-------------------------------------------------------|
|
||||
| Format | glTF 2.0 / GLB (GLB preferred for runtime) |
|
||||
| Skeleton | Single canonical humanoid skeleton, name-based merge |
|
||||
| Slots | Fixed slot registry; exclusive body parts + layered attachments |
|
||||
| Loadout | Compact JSON; server-authoritative and validated |
|
||||
| Replication | Full loadout on spawn/change + `loadout_hash` |
|
||||
| Runtime | Godot `Skeleton3D` + name-based skin re-targeting |
|
||||
| Validation | Build-time asset checker + runtime catalog validation |
|
||||
@@ -0,0 +1,426 @@
|
||||
# Content Moderation & Age Verification Architecture
|
||||
|
||||
> **Status:** Proposed
|
||||
> **Owner:** Platform team
|
||||
> **Related:** Server authority + client prediction, avatar component system, backend auth (JWT)
|
||||
|
||||
## 1. Overview
|
||||
|
||||
This document specifies the **content moderation** and **age verification**
|
||||
architecture for **agp-game**, a Godot-based multiplayer game built by
|
||||
autonomous agents. It defines:
|
||||
|
||||
- How **content flags** propagate through the system across the three primary
|
||||
content types: **assets**, **rooms**, and **scripts**.
|
||||
- How flags are **evaluated, aggregated, and enforced** at load time, at
|
||||
runtime, and at the network boundary.
|
||||
- The **age verification flow**, combining a lightweight **self-declaration**
|
||||
with an optional **ID check hook** for higher-assurance verification.
|
||||
|
||||
The goal is a **single, consistent moderation pipeline** that applies the same
|
||||
rules to user-generated content (UGC) regardless of whether it is a 3D asset, a
|
||||
room definition, or a script, and that gates access to mature content behind a
|
||||
verifiable age gate.
|
||||
|
||||
### 1.1 Design Goals
|
||||
|
||||
- **Uniformity:** One flag vocabulary and one propagation mechanism across
|
||||
assets, rooms, and scripts.
|
||||
- **Composability:** Flags on a room aggregate the flags of the assets and
|
||||
scripts it contains; flags on a world aggregate the flags of its rooms.
|
||||
- **Enforcement at the boundary:** The server is authoritative for what content
|
||||
a client may load or receive, mirroring the server-authoritative networking
|
||||
model.
|
||||
- **Privacy-preserving age checks:** Self-declaration requires no PII; the ID
|
||||
check hook is optional, pluggable, and never stores raw identity documents.
|
||||
- **Auditability:** Every flag decision is logged with a reason, an actor, and
|
||||
a timestamp so moderation actions are reviewable.
|
||||
|
||||
---
|
||||
|
||||
## 2. Content Flag Vocabulary
|
||||
|
||||
All content carries a set of **content flags**. A flag is a typed, immutable
|
||||
label with a **severity** and a **scope**. Flags are the atomic unit of
|
||||
moderation; everything else (aggregation, enforcement, gating) operates on
|
||||
flags.
|
||||
|
||||
### 2.1 Flag Definition
|
||||
|
||||
A flag is a structured record:
|
||||
|
||||
| Field | Type | Description |
|
||||
|------------|-----------|--------------------------------------------------------------------------|
|
||||
| `id` | `string` | Stable machine-readable identifier, e.g. `violence.gore`. |
|
||||
| `label` | `string` | Human-readable name, e.g. "Graphic Gore". |
|
||||
| `category` | `enum` | One of `violence`, `sexual`, `language`, `substance`, `gambling`, `horror`, `hate`, `custom`. |
|
||||
| `severity` | `enum` | One of `none`, `mild`, `moderate`, `severe`. |
|
||||
| `scope` | `enum` | One of `visual`, `audio`, `text`, `behavior`, `interaction`. |
|
||||
| `mature` | `bool` | Whether this flag triggers the age gate (see §5). |
|
||||
| `reason` | `string` | Free-text justification supplied by the flagger. |
|
||||
| `source` | `enum` | One of `author`, `moderator`, `automated`, `community`. |
|
||||
|
||||
### 2.2 Canonical Flag Set
|
||||
|
||||
The platform defines a **canonical registry** of flags so that different
|
||||
content types and different flaggers use the same vocabulary. Examples:
|
||||
|
||||
| id | category | severity | scope | mature |
|
||||
|-----------------------------|------------|-----------|--------------|--------|
|
||||
| `violence.none` | violence | none | visual | false |
|
||||
| `violence.mild` | violence | mild | visual | false |
|
||||
| `violence.gore` | violence | severe | visual | true |
|
||||
| `sexual.suggestive` | sexual | mild | visual | true |
|
||||
| `sexual.explicit` | sexual | severe | visual | true |
|
||||
| `language.mild` | language | mild | text | false |
|
||||
| `language.profanity` | language | moderate | text | false |
|
||||
| `substance.references` | substance | mild | text | false |
|
||||
| `gambling.simulated` | gambling | moderate | behavior | true |
|
||||
| `horror.jumpscare` | horror | mild | audio/visual | false |
|
||||
| `hate.hateful` | hate | severe | text | true |
|
||||
|
||||
The registry is **data-driven** (a JSON/YAML manifest shipped with the server)
|
||||
so new flags can be added without code changes.
|
||||
|
||||
---
|
||||
|
||||
## 3. Flag Propagation Model
|
||||
|
||||
Flags propagate through the system along the **content dependency graph**. The
|
||||
three content types form a hierarchy:
|
||||
|
||||
```
|
||||
World
|
||||
└── Room
|
||||
├── Asset (mesh, texture, audio, animation, material)
|
||||
└── Script (behavior, dialogue, event logic)
|
||||
```
|
||||
|
||||
### 3.1 Propagation Rules
|
||||
|
||||
1. **Explicit flags** are set directly on a content item by its author or a
|
||||
moderator.
|
||||
2. **Inherited flags** flow upward: a room's effective flag set is the **union**
|
||||
of its own explicit flags and the flags of every asset and script it
|
||||
references.
|
||||
3. **Aggregation** uses the **maximum severity** per category across all
|
||||
contributing items. A room containing one `violence.gore` asset and one
|
||||
`violence.none` asset is `violence.severe`.
|
||||
4. **Maturity is monotonic:** if any contributing item is `mature`, the
|
||||
containing room and world are `mature`.
|
||||
5. **Cycles are impossible** by construction: content references form a DAG
|
||||
(an asset cannot contain a room; a room cannot contain itself).
|
||||
|
||||
### 3.2 Propagation Through the Pipeline
|
||||
|
||||
Flags are attached at **authoring time** and carried through every stage:
|
||||
|
||||
```
|
||||
Authoring ──► Upload ──► Validation ──► Storage ──► Distribution ──► Runtime
|
||||
│ │ │ │ │ │
|
||||
│ flag │ flag │ automated │ flag │ flag │ flag
|
||||
│ declared │ preserved │ scan adds │ indexed │ re-checked │ enforced
|
||||
│ │ │ flags │ │ │
|
||||
```
|
||||
|
||||
| Stage | Responsibility |
|
||||
|--------------|-------------------------------------------------------------------------|
|
||||
| **Authoring**| Author declares flags in the editor/upload UI. |
|
||||
| **Upload** | Flags are validated against the canonical registry; unknown flags rejected. |
|
||||
| **Validation**| Automated scanner (hash-based + heuristic) adds flags for detected content. |
|
||||
| **Storage** | Flags are stored alongside the content record and indexed for queries. |
|
||||
| **Distribution**| Flags are re-checked against the current registry before serving. |
|
||||
| **Runtime** | The client enforces flags before loading content (see §4). |
|
||||
|
||||
### 3.3 Data Model
|
||||
|
||||
Flags are stored as a **normalized join table** so they can be queried and
|
||||
aggregated efficiently:
|
||||
|
||||
```
|
||||
content_item (id, type, owner_id, ...)
|
||||
content_flag (content_id, flag_id, source, reason, created_at, actor_id)
|
||||
flag_registry (id, category, severity, scope, mature, ...)
|
||||
```
|
||||
|
||||
Aggregation is computed by a SQL view / query that joins a content item's
|
||||
transitive dependencies. Because the graph is a DAG, this is a bounded
|
||||
recursive query (PostgreSQL `WITH RECURSIVE`).
|
||||
|
||||
---
|
||||
|
||||
## 4. Enforcement
|
||||
|
||||
Enforcement happens at three layers, in order:
|
||||
|
||||
### 4.1 Load-Time Enforcement (Server)
|
||||
|
||||
Before a client is allowed to **request** content, the server evaluates the
|
||||
content's effective flag set against the requesting account's **content
|
||||
preferences** and **age verification status**:
|
||||
|
||||
- If the content is `mature` and the account is **not age-verified**, the
|
||||
request is **rejected** with a `403 MATURE_CONTENT_REQUIRES_VERIFICATION`.
|
||||
- If the content's flags exceed the account's **content filter** (a per-account
|
||||
severity threshold per category), the request is rejected or the offending
|
||||
content is **stripped** (e.g., audio muted, mesh hidden, script not loaded).
|
||||
|
||||
### 4.2 Runtime Enforcement (Client)
|
||||
|
||||
The client receives a **manifest** of allowed content from the server. It never
|
||||
loads content that is not in the manifest. This prevents a malicious or buggy
|
||||
client from bypassing the server's filter by loading content directly.
|
||||
|
||||
- Assets not in the manifest are **not instantiated**.
|
||||
- Scripts not in the manifest are **not executed**.
|
||||
- Rooms not in the manifest are **not entered**.
|
||||
|
||||
### 4.3 Network Boundary Enforcement
|
||||
|
||||
The server **filters replication** based on flags:
|
||||
|
||||
- Mature or filtered content is **not replicated** to clients that cannot
|
||||
receive it.
|
||||
- A room's flag set is broadcast in the room metadata so clients can show a
|
||||
warning before entry.
|
||||
|
||||
### 4.4 Enforcement Decision Flow
|
||||
|
||||
```
|
||||
Client requests content C for account A
|
||||
│
|
||||
▼
|
||||
Compute effective flags F(C) [union + max-severity aggregation]
|
||||
│
|
||||
▼
|
||||
Is A age-verified? ──no──► Is F(C).mature? ──yes──► REJECT (403)
|
||||
│ yes │ no
|
||||
▼ ▼
|
||||
Does F(C) exceed A's filter? ──► yes ──► REJECT or STRIP
|
||||
│ no
|
||||
▼
|
||||
Serve content + manifest
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 5. Age Verification Flow
|
||||
|
||||
Age verification is a **two-tier** system:
|
||||
|
||||
- **Tier 1 — Self-declaration:** The user asserts their date of birth. This is
|
||||
fast, requires no PII beyond a birthdate, and is sufficient for most content.
|
||||
- **Tier 2 — ID check (optional hook):** A pluggable identity-verification
|
||||
provider confirms the user is an adult. This raises the account's assurance
|
||||
level and unlocks the highest maturity tier.
|
||||
|
||||
### 5.1 Verification States
|
||||
|
||||
An account has an **age verification status**:
|
||||
|
||||
| Status | Meaning |
|
||||
|-------------------|----------------------------------------------------------------------|
|
||||
| `unverified` | No declaration on file. |
|
||||
| `self_declared` | User declared a birthdate; **not** independently confirmed. |
|
||||
| `id_verified` | User passed the ID check hook; independently confirmed adult. |
|
||||
| `rejected` | ID check failed or declaration was inconsistent. |
|
||||
|
||||
### 5.2 Tier 1 — Self-Declaration Flow
|
||||
|
||||
```
|
||||
User submits { date_of_birth }
|
||||
│
|
||||
▼
|
||||
Server validates format & plausibility (age 13–120, not in future)
|
||||
│
|
||||
▼
|
||||
Compute age from DOB
|
||||
│
|
||||
▼
|
||||
age >= 18 ──► status = self_declared (adult)
|
||||
age >= 13 ──► status = self_declared (minor, restricted)
|
||||
age < 13 ──► status = rejected (below minimum platform age)
|
||||
```
|
||||
|
||||
- The DOB is stored **encrypted at rest** and is **never exposed** to other
|
||||
players.
|
||||
- A user may **upgrade** from `self_declared` to `id_verified` at any time via
|
||||
Tier 2.
|
||||
|
||||
### 5.3 Tier 2 — ID Check Hook
|
||||
|
||||
The ID check is an **optional, pluggable hook**. The platform defines an
|
||||
interface; concrete providers (e.g., a third-party KYC service) implement it.
|
||||
|
||||
```
|
||||
User requests ID verification
|
||||
│
|
||||
▼
|
||||
Server creates a verification session (idempotent, expiring)
|
||||
│
|
||||
▼
|
||||
Server calls provider hook: verify(identity_token) -> { adult: bool, ref: string }
|
||||
│
|
||||
▼
|
||||
adult == true ──► status = id_verified, store provider ref (not raw doc)
|
||||
adult == false ─► status = rejected
|
||||
provider error ──► status unchanged, retry allowed
|
||||
```
|
||||
|
||||
**Privacy guarantees:**
|
||||
|
||||
- The platform **never stores** the raw identity document or image.
|
||||
- Only the provider's **opaque reference** and the boolean `adult` result are
|
||||
persisted.
|
||||
- The hook is **asynchronous and idempotent**; a session can be retried without
|
||||
double-charging or double-verifying.
|
||||
|
||||
### 5.4 Hook Interface
|
||||
|
||||
The ID check hook is defined as a backend interface (FastAPI dependency /
|
||||
abstract service):
|
||||
|
||||
```python
|
||||
class IdentityVerificationProvider(Protocol):
|
||||
def create_session(self, user_id: str) -> VerificationSession: ...
|
||||
def verify(self, session_id: str, identity_token: str) -> VerificationResult: ...
|
||||
|
||||
class VerificationResult:
|
||||
adult: bool
|
||||
provider_ref: str | None
|
||||
error: str | None
|
||||
```
|
||||
|
||||
A default **no-op provider** returns `adult=False` with a clear error, so the
|
||||
system runs without any third-party integration until one is configured.
|
||||
|
||||
### 5.5 Age Gate Enforcement
|
||||
|
||||
The age gate is enforced at **load time** (see §4.1):
|
||||
|
||||
| Verification status | Can access `mature` content? |
|
||||
|---------------------|------------------------------|
|
||||
| `unverified` | No |
|
||||
| `self_declared` | Yes (adult) / No (minor) |
|
||||
| `id_verified` | Yes |
|
||||
| `rejected` | No |
|
||||
|
||||
---
|
||||
|
||||
## 6. Moderation Workflow
|
||||
|
||||
### 6.1 Flagging Sources
|
||||
|
||||
Content can be flagged by:
|
||||
|
||||
- **Author** (self-declared at upload).
|
||||
- **Automated scanner** (hash-based detection, heuristic analysis).
|
||||
- **Community** (players report content; reports become flags after review).
|
||||
- **Moderator** (manual review and override).
|
||||
|
||||
### 6.2 Review Queue
|
||||
|
||||
Community and automated flags enter a **review queue**. A moderator either:
|
||||
|
||||
- **Approves** the flag (it becomes authoritative), or
|
||||
- **Rejects** the flag (it is discarded), or
|
||||
- **Escalates** to a senior moderator for severe/hate flags.
|
||||
|
||||
### 6.3 Actions
|
||||
|
||||
Once a flag is authoritative, a moderator can take actions:
|
||||
|
||||
| Action | Effect |
|
||||
|-----------------|---------------------------------------------------------------|
|
||||
| `warn` | Notify the author; content remains. |
|
||||
| `restrict` | Content hidden from users below a filter threshold. |
|
||||
| `age_gate` | Content marked `mature`; requires age verification. |
|
||||
| `remove` | Content taken down; not served. |
|
||||
| `ban_author` | Author's upload privileges suspended. |
|
||||
|
||||
### 6.4 Audit Log
|
||||
|
||||
Every flag and action is written to an **audit log**:
|
||||
|
||||
```
|
||||
audit_event (id, content_id, actor_id, action, flag_id, reason, created_at)
|
||||
```
|
||||
|
||||
This log is append-only and used for transparency and dispute resolution.
|
||||
|
||||
---
|
||||
|
||||
## 7. Client-Side Integration (Godot)
|
||||
|
||||
### 7.1 Content Manifest
|
||||
|
||||
The server sends each client a **content manifest** — the set of content the
|
||||
client is permitted to load, derived from the account's verification status and
|
||||
filter. The Godot client:
|
||||
|
||||
- Loads only manifest-listed assets.
|
||||
- Executes only manifest-listed scripts.
|
||||
- Shows a **maturity warning** dialog before entering a room whose effective
|
||||
flags include `mature` content.
|
||||
|
||||
### 7.2 Flag Metadata on Content
|
||||
|
||||
Each content resource carries a `content_flags` metadata field (a Godot
|
||||
`Dictionary` or custom `Resource`). The client uses this for local UI decisions
|
||||
(e.g., showing a warning icon) but **never** as the authority for whether to
|
||||
load — the server manifest is authoritative.
|
||||
|
||||
### 7.3 Age Verification UI
|
||||
|
||||
The client exposes an **age verification screen**:
|
||||
|
||||
- Tier 1: a date-of-birth picker.
|
||||
- Tier 2: a button that opens the ID check provider flow (deep link / webview).
|
||||
|
||||
The client calls the backend endpoints (§8) and reflects the resulting status.
|
||||
|
||||
---
|
||||
|
||||
## 8. Backend API Surface
|
||||
|
||||
| Method | Path | Description |
|
||||
|--------|-----------------------------------|------------------------------------------------|
|
||||
| `POST` | `/v1/age/declare` | Submit self-declared DOB (Tier 1). |
|
||||
| `POST` | `/v1/age/verify/session` | Create an ID-check session (Tier 2). |
|
||||
| `POST` | `/v1/age/verify/confirm` | Confirm an ID-check session with a token. |
|
||||
| `GET` | `/v1/age/status` | Return the account's verification status. |
|
||||
| `GET` | `/v1/content/{id}/flags` | Return a content item's effective flags. |
|
||||
| `POST` | `/v1/content/{id}/flags` | Add a flag (author/community). |
|
||||
| `POST` | `/v1/moderation/review/{flag_id}` | Moderator approve/reject/escalate. |
|
||||
| `POST` | `/v1/moderation/action` | Apply a moderation action. |
|
||||
| `GET` | `/v1/manifest` | Return the client's permitted content manifest.|
|
||||
|
||||
All endpoints require a valid **JWT** (matching the existing auth stack). The
|
||||
age endpoints additionally require the account to be in a non-`rejected` state.
|
||||
|
||||
---
|
||||
|
||||
## 9. Security & Privacy Considerations
|
||||
|
||||
- **DOB encryption:** Self-declared birthdates are encrypted at rest; only the
|
||||
derived age and verification status are used in authorization decisions.
|
||||
- **No raw identity storage:** The ID check hook persists only a provider
|
||||
reference and a boolean result.
|
||||
- **Server authority:** The client manifest prevents bypass; the client never
|
||||
trusts its own flag metadata for access decisions.
|
||||
- **Rate limiting:** Age-declaration and ID-check endpoints are rate-limited to
|
||||
prevent abuse and enumeration.
|
||||
- **Auditability:** All flag and verification events are logged append-only.
|
||||
|
||||
---
|
||||
|
||||
## 10. Open Questions / Future Work
|
||||
|
||||
- **Regional age thresholds:** Different jurisdictions may require different
|
||||
minimum ages; the threshold should be configurable per region.
|
||||
- **Parental controls:** A future feature may let a parent set a content filter
|
||||
on a minor's account.
|
||||
- **Automated scanner accuracy:** The heuristic scanner may produce false
|
||||
positives; a confidence score should be attached to automated flags.
|
||||
- **Offline / local content:** How flags apply to locally-authored content that
|
||||
is never uploaded remains to be defined.
|
||||
@@ -0,0 +1,286 @@
|
||||
# Multiplayer Networking Architecture
|
||||
|
||||
> **Status:** Proposed
|
||||
> **Owner:** Platform team
|
||||
> **Related:** Server authority + client prediction
|
||||
|
||||
## 1. Overview
|
||||
|
||||
This document specifies the multiplayer networking architecture for **agp-game**,
|
||||
a Godot-based game built by autonomous agents. The architecture follows a
|
||||
**server-authoritative model with client-side prediction and reconciliation**,
|
||||
which is the industry standard for fast-paced, competitive multiplayer games.
|
||||
|
||||
The goals of this architecture are:
|
||||
|
||||
- **Fairness & anti-cheat:** The server is the single source of truth for all
|
||||
gameplay state. Clients never directly mutate world state.
|
||||
- **Responsiveness:** Client-side prediction hides network latency so local input
|
||||
feels immediate.
|
||||
- **Determinism:** The server runs a fixed-timestep simulation so that state is
|
||||
reproducible and testable.
|
||||
- **Scalability:** A clear separation between transport, simulation, and
|
||||
replication layers allows the server to be tuned independently.
|
||||
|
||||
---
|
||||
|
||||
## 2. Transport Choice: ENet over WebSocket
|
||||
|
||||
### 2.1 Decision
|
||||
|
||||
We choose **ENet** as the primary transport for gameplay traffic.
|
||||
|
||||
### 2.2 Justification
|
||||
|
||||
| Criterion | ENet | WebSocket (TCP) |
|
||||
|----------------------|----------------------------------------|-------------------------------------|
|
||||
| **Reliability model**| Reliable + unreliable channels | Reliable only (TCP) |
|
||||
| **Latency** | Low; unreliable packets skip retransmit| Head-of-line blocking on loss |
|
||||
| **Packet ordering** | Per-channel ordering | Global strict ordering |
|
||||
| **Congestion control**| Lightweight, game-oriented | TCP-style (slow start, backoff) |
|
||||
| **Godot support** | First-class (`ENetConnection`, `MultiplayerPeerENet`) | Supported but TCP-based |
|
||||
| **Use case fit** | Real-time action game | Chat, lobby, HTTP-style messaging |
|
||||
|
||||
**Rationale:**
|
||||
|
||||
- **Movement & state replication** are latency-sensitive and tolerate occasional
|
||||
packet loss. ENet's *unreliable* channel lets us send position snapshots at high
|
||||
frequency without head-of-line blocking.
|
||||
- **RPCs that must be delivered** (e.g., interactions, spawns) use ENet's
|
||||
*reliable* channel, giving us exactly the semantics we need without TCP's
|
||||
retransmission stalls.
|
||||
- Godot's `MultiplayerPeerENet` is mature and integrates directly with the
|
||||
high-level multiplayer API (`MultiplayerAPI`, `rpc()`).
|
||||
|
||||
### 2.3 WebSocket as a Secondary Transport
|
||||
|
||||
WebSocket remains available as a **secondary transport** for:
|
||||
|
||||
- **Lobby / matchmaking** messaging (low-frequency, must-be-reliable).
|
||||
- **Browser builds** where raw UDP/ENet is unavailable.
|
||||
- **Admin / telemetry** channels.
|
||||
|
||||
The transport layer is abstracted behind an interface so gameplay code does not
|
||||
depend on the underlying protocol.
|
||||
|
||||
---
|
||||
|
||||
## 3. Server-Side Game Loop
|
||||
|
||||
### 3.1 Tick Rate
|
||||
|
||||
- **Simulation tick rate:** **30 Hz** (33.33 ms per tick).
|
||||
- **Replication / snapshot rate:** **30 Hz**, aligned with the simulation tick.
|
||||
|
||||
**Justification:**
|
||||
|
||||
- 30 Hz is sufficient for smooth movement and interaction in a top-down / 2D
|
||||
action game while keeping CPU and bandwidth costs predictable.
|
||||
- A fixed timestep (rather than delta-time) makes the simulation deterministic
|
||||
and testable.
|
||||
- The tick rate is a **configuration constant** so it can be raised (e.g., to
|
||||
60 Hz) for competitive modes without architectural changes.
|
||||
|
||||
### 3.2 Authority Model
|
||||
|
||||
- **Server is authoritative** for:
|
||||
- Player position, velocity, and physics state.
|
||||
- Health, damage, and death.
|
||||
- Item pickups, inventory, and world-object state.
|
||||
- Spawning and despawning of entities.
|
||||
- Game rules, scoring, and win/lose conditions.
|
||||
- **Client is authoritative** for:
|
||||
- Its own *input* (which keys/buttons are pressed).
|
||||
- Local camera and UI.
|
||||
- Cosmetic / non-gameplay presentation.
|
||||
|
||||
### 3.3 Server Loop Pseudocode
|
||||
|
||||
```
|
||||
while server_running:
|
||||
process_network_inbound() # read client inputs & RPCs
|
||||
for _ in range(ticks_to_advance):
|
||||
simulate_tick() # fixed 30 Hz step
|
||||
broadcast_snapshots() # replicate authoritative state
|
||||
process_network_outbound() # flush reliable/unreliable channels
|
||||
```
|
||||
|
||||
The server accumulates real elapsed time and advances the simulation in fixed
|
||||
`TICK_DURATION` increments, decoupling simulation from frame rate.
|
||||
|
||||
---
|
||||
|
||||
## 4. RPC Call Patterns
|
||||
|
||||
RPCs are grouped by direction and reliability. All gameplay RPCs are routed
|
||||
through the high-level `MultiplayerAPI` with explicit `rpc_id` targeting.
|
||||
|
||||
### 4.1 Client → Server (Input & Requests)
|
||||
|
||||
| RPC | Channel | Payload | Notes |
|
||||
|------------------------------|-----------|-------------------------------------------|-------|
|
||||
| `request_move_input` | unreliable| `{ seq, input_state, timestamp }` | Batched per tick; drives prediction |
|
||||
| `request_interact` | reliable | `{ target_id }` | Open door, pick up item, use object |
|
||||
| `request_attack` | reliable | `{ target_id, aim_dir }` | Combat action |
|
||||
| `request_join` | reliable | `{ player_name, profile }` | Session setup |
|
||||
| `request_respawn` | reliable | `{}` | After death |
|
||||
|
||||
**Design notes:**
|
||||
|
||||
- **Input is batched** per client tick and sent with a monotonically increasing
|
||||
`seq` so the server can detect gaps and the client can reconcile.
|
||||
- **Interactions are reliable** because they are discrete, must-happen events
|
||||
(opening a door, picking up an item). Losing them would corrupt world state.
|
||||
|
||||
### 4.2 Server → Client (State & Events)
|
||||
|
||||
| RPC | Channel | Payload | Notes |
|
||||
|------------------------------|-----------|-------------------------------------------|-------|
|
||||
| `snapshot_state` | unreliable| `{ tick, entities[], player_states[] }` | Periodic authoritative state |
|
||||
| `spawn_entity` | reliable | `{ entity_id, type, transform, props }` | New entity enters world |
|
||||
| `despawn_entity` | reliable | `{ entity_id, reason }` | Entity removed |
|
||||
| `interact_result` | reliable | `{ request_seq, success, result }` | Acknowledges interaction |
|
||||
| `damage_event` | reliable | `{ target_id, amount, source_id }` | Combat feedback |
|
||||
| `game_event` | reliable | `{ type, payload }` | Score, win, round start/end |
|
||||
|
||||
### 4.3 Broadcast vs. Targeted
|
||||
|
||||
- **Broadcast (all clients):** `snapshot_state`, `spawn_entity`,
|
||||
`despawn_entity`, `game_event`.
|
||||
- **Targeted (single client):** `interact_result`, `damage_event` (to affected
|
||||
players), and any player-private data.
|
||||
|
||||
---
|
||||
|
||||
## 5. Client-Side Prediction & Reconciliation
|
||||
|
||||
### 5.1 Prediction
|
||||
|
||||
- The client runs a **local copy of the movement simulation** using the same
|
||||
physics constants as the server.
|
||||
- When the player provides input, the client:
|
||||
1. Applies the input to its local player immediately.
|
||||
2. Renders the predicted position.
|
||||
3. Sends the input to the server (batched, with `seq`).
|
||||
|
||||
### 5.2 Reconciliation
|
||||
|
||||
- The server sends authoritative `snapshot_state` at 30 Hz containing the
|
||||
server's tick number and authoritative player positions.
|
||||
- The client keeps a **ring buffer of predicted states** keyed by input `seq`.
|
||||
- On receiving a snapshot:
|
||||
1. Find the last predicted state that matches the server's tick.
|
||||
2. Compute the **error** between predicted and authoritative position.
|
||||
3. If error exceeds a threshold, **snap or smoothly interpolate** the local
|
||||
player to the authoritative position (error correction).
|
||||
4. Re-simulate any inputs that occurred after the server's tick (rollback).
|
||||
|
||||
### 5.3 Interpolation of Remote Entities
|
||||
|
||||
- **Local player:** predicted + reconciled (see above).
|
||||
- **Remote players / entities:** rendered with **interpolation delay** of
|
||||
`2 × TICK_DURATION` (≈ 66 ms) to smooth out snapshot jitter.
|
||||
- The client buffers the last N snapshots and interpolates between them.
|
||||
|
||||
### 5.4 Prediction Buffer Sizing
|
||||
|
||||
- Buffer size is adaptive based on measured RTT.
|
||||
- Default: hold up to `ceil(RTT / TICK_DURATION) + 2` predicted states.
|
||||
|
||||
---
|
||||
|
||||
## 6. Entity & World State Replication
|
||||
|
||||
### 6.1 Entity Model
|
||||
|
||||
Every networked entity has:
|
||||
|
||||
- A globally unique `entity_id` (server-assigned).
|
||||
- An `EntityType` (player, enemy, item, projectile, door, ...).
|
||||
- A `Transform` (position, rotation).
|
||||
- A typed `props` dictionary of gameplay state (health, state machine, etc.).
|
||||
|
||||
### 6.2 Snapshot Format
|
||||
|
||||
```
|
||||
snapshot_state:
|
||||
tick: uint32
|
||||
entities:
|
||||
- entity_id: uint32
|
||||
type: uint8
|
||||
transform: { x, y, rot }
|
||||
props: { ... } # delta-encoded where possible
|
||||
player_states:
|
||||
- peer_id: int
|
||||
entity_id: uint32
|
||||
health: int
|
||||
state: uint8
|
||||
```
|
||||
|
||||
### 6.3 Delta Compression
|
||||
|
||||
- Only **changed** entity fields are sent per snapshot (dirty-flag per entity).
|
||||
- Static or unchanged entities are omitted from the snapshot.
|
||||
- This keeps bandwidth proportional to *activity*, not world size.
|
||||
|
||||
---
|
||||
|
||||
## 7. Connection & Session Lifecycle
|
||||
|
||||
1. **Connect:** Client opens an ENet connection to the server.
|
||||
2. **Authenticate / Join:** Client sends `request_join`; server validates and
|
||||
assigns a `peer_id` and spawns the player entity.
|
||||
3. **Spawn:** Server broadcasts `spawn_entity` for the new player to all clients.
|
||||
4. **Play:** Input → prediction → server simulation → snapshot → reconciliation.
|
||||
5. **Disconnect:** Server removes the player entity, broadcasts `despawn_entity`,
|
||||
and cleans up session state.
|
||||
|
||||
---
|
||||
|
||||
## 8. Security & Anti-Cheat
|
||||
|
||||
- **No client-authoritative gameplay values.** Clients only send *inputs* and
|
||||
*requests*; the server computes all outcomes.
|
||||
- **Input validation:** Server clamps movement speed, rejects out-of-bounds
|
||||
positions, and validates interaction targets.
|
||||
- **Rate limiting:** Per-peer input and RPC rate limits prevent flooding.
|
||||
- **Sequence validation:** Gaps or replays in input `seq` are detected and
|
||||
rejected.
|
||||
|
||||
---
|
||||
|
||||
## 9. Testing & Determinism
|
||||
|
||||
- The simulation is a **pure function of (state, inputs, tick)** so it can be
|
||||
unit-tested headlessly.
|
||||
- A **replay system** records inputs and can re-simulate to verify server and
|
||||
client produce identical results.
|
||||
- Network code is tested with a **mock transport** that can inject latency,
|
||||
jitter, and packet loss.
|
||||
|
||||
---
|
||||
|
||||
## 10. Open Questions / Future Work
|
||||
|
||||
- **Interest management / spatial partitioning:** For large worlds, restrict
|
||||
snapshots to entities near each client (AOI culling).
|
||||
- **Server-side physics:** Decide whether to use Godot's physics server on the
|
||||
host or a custom deterministic physics step.
|
||||
- **Dedicated server vs. listen server:** The architecture supports both; a
|
||||
dedicated headless server is the target for production.
|
||||
- **WebSocket fallback:** Implement the transport abstraction for browser builds.
|
||||
|
||||
---
|
||||
|
||||
## 11. Summary
|
||||
|
||||
| Concern | Decision |
|
||||
|------------------------|-------------------------------------------------|
|
||||
| Transport | ENet (primary), WebSocket (secondary) |
|
||||
| Tick rate | 30 Hz fixed timestep |
|
||||
| Authority | Server-authoritative; client sends input only |
|
||||
| Prediction | Client-side prediction + reconciliation |
|
||||
| Remote interpolation | 2-tick interpolation delay |
|
||||
| Replication | Delta-compressed snapshots at 30 Hz |
|
||||
| Interaction RPCs | Reliable channel |
|
||||
| Movement input | Unreliable channel, batched with sequence |
|
||||
@@ -0,0 +1,737 @@
|
||||
# World Chunk Data Format & Persistence Architecture
|
||||
|
||||
> **Status:** Proposed
|
||||
> **Owner:** Platform team
|
||||
> **Related:** Server authority + client prediction, avatar component system, content moderation & age verification, backend auth (JWT)
|
||||
|
||||
## 1. Overview
|
||||
|
||||
This document specifies the **world chunk data format** and **persistence
|
||||
schema** for **agp-game**, a Godot-based multiplayer game built by autonomous
|
||||
agents. It defines:
|
||||
|
||||
- The **chunk data format** — both a human-readable **JSON** form (for
|
||||
authoring, tooling, and debugging) and a compact **binary** form (for
|
||||
runtime loading and network transfer).
|
||||
- The **SQLite schema** that persists world state on the server, including
|
||||
chunk metadata, chunk payloads, and the world/room hierarchy.
|
||||
- The **read/write API** that the server and client use to load, save, and
|
||||
stream chunks.
|
||||
|
||||
The goal is a **single, versioned chunk contract** that is shared across the
|
||||
Godot client, the Python backend, and the persistence layer. A chunk is the
|
||||
atomic unit of world geometry, gameplay objects, and persistence — the server
|
||||
loads and saves whole chunks, and clients stream the chunks around them.
|
||||
|
||||
### 1.1 Design Goals
|
||||
|
||||
- **Versioned & forward-compatible:** Every chunk carries a format version so
|
||||
the loader can migrate old data and reject unknown future data gracefully.
|
||||
- **Dual representation:** JSON for authoring/debugging, binary for
|
||||
runtime/network. Both encode the *same* logical model so there is exactly one
|
||||
source of truth for the schema.
|
||||
- **Server-authoritative persistence:** The server is the only writer to the
|
||||
SQLite store. Clients submit *edits* (deltas) and the server applies and
|
||||
persists them, mirroring the server-authoritative networking model.
|
||||
- **Chunk-granular persistence:** Persistence happens at chunk granularity so
|
||||
the server can save a dirty chunk without rewriting the whole world, and can
|
||||
stream only the chunks a client needs.
|
||||
- **Deterministic & testable:** The binary format is byte-stable for a given
|
||||
logical payload, enabling checksums, caching, and reproducible tests.
|
||||
- **Moderation-aware:** Chunks reference content (assets, scripts) that carry
|
||||
content flags (see `content_moderation.md`); the persistence layer stores the
|
||||
moderation state alongside chunk data so enforcement can happen at load time.
|
||||
|
||||
---
|
||||
|
||||
## 2. World Model & Chunking
|
||||
|
||||
### 2.1 World Hierarchy
|
||||
|
||||
The world is organized as a hierarchy that matches the moderation content graph:
|
||||
|
||||
```
|
||||
World
|
||||
└── Room
|
||||
└── Chunk (the atomic persistence & streaming unit)
|
||||
├── Tiles / Terrain
|
||||
├── Static objects (props, geometry)
|
||||
├── Dynamic objects (spawnable entities, interactables)
|
||||
└── Metadata (flags, version, timestamps)
|
||||
```
|
||||
|
||||
- A **World** is the top-level container (a named, versioned space).
|
||||
- A **Room** is a bounded region within a world (a level, a building, a zone).
|
||||
- A **Chunk** is a fixed-size, axis-aligned region of a room. It is the unit of
|
||||
load, save, and stream.
|
||||
|
||||
### 2.2 Chunk Dimensions
|
||||
|
||||
Chunks are **fixed-size, axis-aligned boxes** in world space. The default
|
||||
dimensions are a configuration constant so they can be tuned per world:
|
||||
|
||||
| Constant | Default | Description |
|
||||
|---------------------|---------|----------------------------------------------------|
|
||||
| `CHUNK_SIZE_X` | 32 | Chunk width in world units (tiles). |
|
||||
| `CHUNK_SIZE_Y` | 32 | Chunk height in world units (tiles). |
|
||||
| `CHUNK_SIZE_Z` | 1 | Chunk depth (1 = flat 2D world; >1 = volumetric). |
|
||||
| `CHUNK_ORIGIN` | `(0,0)` | World-space origin of chunk coordinate `(0,0)`. |
|
||||
|
||||
A chunk is identified by its **integer chunk coordinate** `(cx, cy, cz)`,
|
||||
computed from a world-space position `p` as:
|
||||
|
||||
```
|
||||
cx = floor((p.x - CHUNK_ORIGIN.x) / CHUNK_SIZE_X)
|
||||
cy = floor((p.y - CHUNK_ORIGIN.y) / CHUNK_SIZE_Y)
|
||||
cz = floor((p.z - CHUNK_ORIGIN.z) / CHUNK_SIZE_Z)
|
||||
```
|
||||
|
||||
The chunk's world-space bounding box is therefore:
|
||||
|
||||
```
|
||||
min = (CHUNK_ORIGIN.x + cx*CHUNK_SIZE_X, ...)
|
||||
max = min + (CHUNK_SIZE_X, CHUNK_SIZE_Y, CHUNK_SIZE_Z)
|
||||
```
|
||||
|
||||
### 2.3 Chunk Coordinate Key
|
||||
|
||||
For storage and lookup, a chunk is addressed by a **canonical string key**:
|
||||
|
||||
```
|
||||
"{world_id}:{room_id}:{cx}:{cy}:{cz}"
|
||||
```
|
||||
|
||||
Example: `"w_0001:r_0001:12:-4:0"`. This key is the primary lookup key in the
|
||||
SQLite `chunks` table and is used in the read/write API.
|
||||
|
||||
---
|
||||
|
||||
## 3. Chunk Data Format
|
||||
|
||||
### 3.1 Logical Model
|
||||
|
||||
Both the JSON and binary encodings serialize the same logical chunk model. The
|
||||
logical model is defined here once; the two encodings are projections of it.
|
||||
|
||||
```
|
||||
Chunk
|
||||
├── version : uint (format version, currently 1)
|
||||
├── key : string (canonical chunk key, see §2.3)
|
||||
├── world_id : string
|
||||
├── room_id : string
|
||||
├── coord : { cx, cy, cz } (int)
|
||||
├── bounds : { min_x, min_y, min_z, max_x, max_y, max_z } (float)
|
||||
├── tiles : TileLayer[] (terrain / tile data)
|
||||
├── objects : WorldObject[] (static + dynamic objects)
|
||||
├── flags : ContentFlags (moderation flags, see §3.5)
|
||||
├── meta : { created_at, updated_at, revision, author }
|
||||
└── checksum : string (SHA-256 of canonical payload)
|
||||
```
|
||||
|
||||
### 3.2 Tile Layer
|
||||
|
||||
A chunk's terrain is stored as one or more **tile layers**. Each layer is a
|
||||
dense grid of tile IDs of size `CHUNK_SIZE_X × CHUNK_SIZE_Y` (× `CHUNK_SIZE_Z`
|
||||
for volumetric worlds).
|
||||
|
||||
```
|
||||
TileLayer
|
||||
├── name : string (e.g. "ground", "walls", "decor")
|
||||
├── layer_id : uint
|
||||
├── width : uint (= CHUNK_SIZE_X)
|
||||
├── height : uint (= CHUNK_SIZE_Y)
|
||||
├── depth : uint (= CHUNK_SIZE_Z)
|
||||
├── tiles : uint[] (flattened tile IDs, row-major, length = w*h*d)
|
||||
└── palette : TileDef[] (tile ID → tile definition, shared per layer)
|
||||
```
|
||||
|
||||
**Tile encoding:** A tile ID is a `uint16` index into the layer's `palette`.
|
||||
`0` is reserved for "empty/air". The palette maps each tile ID to a `TileDef`:
|
||||
|
||||
```
|
||||
TileDef
|
||||
├── id : uint16
|
||||
├── asset_id : string (reference to a tile/terrain asset)
|
||||
├── solid : bool (collision)
|
||||
├── flags : uint32 (bitmask: walkable, climbable, liquid, ...)
|
||||
└── variants : uint8 (number of visual variants for this tile)
|
||||
```
|
||||
|
||||
**Rationale for palette + indices:** Storing dense `uint16` indices rather than
|
||||
full asset strings per cell keeps the binary payload small (2 bytes/cell) while
|
||||
the palette (shared across the layer) carries the rich per-tile metadata.
|
||||
|
||||
### 3.3 World Objects
|
||||
|
||||
Objects are the non-tile entities in a chunk: static props, interactables,
|
||||
spawn points, and dynamic-object templates.
|
||||
|
||||
```
|
||||
WorldObject
|
||||
├── id : string (stable object id, unique within the chunk)
|
||||
├── type : string (e.g. "prop", "interactable", "spawn_point", "door")
|
||||
├── asset_id : string (reference to the object's mesh/glTF asset)
|
||||
├── transform : { pos: [x,y,z], rot: [x,y,z,w], scale: [x,y,z] }
|
||||
├── properties : object (type-specific key/value map, JSON-typed)
|
||||
├── dynamic : bool (true if this is a spawnable dynamic entity)
|
||||
└── flags : ContentFlags (per-object moderation flags)
|
||||
```
|
||||
|
||||
**Dynamic objects** are stored as *templates* in the chunk. Their *runtime
|
||||
state* (position, health, inventory) is **not** stored in the chunk; it lives
|
||||
in the runtime entity store and is persisted separately (see §4.4). This keeps
|
||||
chunks stable and diffable — a chunk only changes when its *static* content
|
||||
changes.
|
||||
|
||||
### 3.4 Content Flags
|
||||
|
||||
Each chunk (and each object) carries a **content flag set** that is the
|
||||
aggregate of the moderation flags of the assets and scripts it references. This
|
||||
mirrors the aggregation rules in `content_moderation.md`:
|
||||
|
||||
```
|
||||
ContentFlags
|
||||
├── categories : { violence, sexual, language, substance, gambling, horror, hate, custom }
|
||||
│ (each → severity: none|mild|moderate|severe)
|
||||
├── mature : bool (true if any contributing item is mature)
|
||||
└── sources : string[] (flag ids that contributed, for audit)
|
||||
```
|
||||
|
||||
The server computes and persists these flags at write time so that enforcement
|
||||
(age gating, content filtering) can happen at load time without re-scanning
|
||||
assets.
|
||||
|
||||
### 3.5 JSON Encoding
|
||||
|
||||
The JSON encoding is the **authoring and debugging** representation. It is
|
||||
human-readable, diffable, and used by tools and tests. It is the canonical
|
||||
logical model serialized directly.
|
||||
|
||||
```json
|
||||
{
|
||||
"version": 1,
|
||||
"key": "w_0001:r_0001:12:-4:0",
|
||||
"world_id": "w_0001",
|
||||
"room_id": "r_0001",
|
||||
"coord": { "cx": 12, "cy": -4, "cz": 0 },
|
||||
"bounds": { "min_x": 384.0, "min_y": -128.0, "min_z": 0.0,
|
||||
"max_x": 416.0, "max_y": -96.0, "max_z": 1.0 },
|
||||
"tiles": [
|
||||
{
|
||||
"name": "ground",
|
||||
"layer_id": 0,
|
||||
"width": 32,
|
||||
"height": 32,
|
||||
"depth": 1,
|
||||
"palette": [
|
||||
{ "id": 0, "asset_id": "", "solid": false, "flags": 0, "variants": 1 },
|
||||
{ "id": 1, "asset_id": "tiles/grass", "solid": false, "flags": 1, "variants": 4 }
|
||||
],
|
||||
"tiles": [0, 1, 1, 1, 0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 1, 1]
|
||||
}
|
||||
],
|
||||
"objects": [
|
||||
{
|
||||
"id": "obj_0001",
|
||||
"type": "interactable",
|
||||
"asset_id": "props/chest",
|
||||
"transform": { "pos": [400.0, -110.0, 0.0],
|
||||
"rot": [0.0, 0.0, 0.0, 1.0],
|
||||
"scale": [1.0, 1.0, 1.0] },
|
||||
"properties": { "loot_table": "chest_basic", "locked": false },
|
||||
"dynamic": false,
|
||||
"flags": { "categories": { "violence": "none" }, "mature": false, "sources": [] }
|
||||
}
|
||||
],
|
||||
"flags": { "categories": { "violence": "none" }, "mature": false, "sources": [] },
|
||||
"meta": { "created_at": "2026-08-17T00:00:00Z",
|
||||
"updated_at": "2026-08-17T00:00:00Z",
|
||||
"revision": 3,
|
||||
"author": "agent-bot" },
|
||||
"checksum": "9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a08"
|
||||
}
|
||||
```
|
||||
|
||||
> **Note on the example checksum:** The value shown above is illustrative only.
|
||||
> In practice the `checksum` field is the SHA-256 of the canonical binary
|
||||
> payload body (see §3.6.3), not of the JSON text. The value here is a
|
||||
> placeholder for documentation purposes.
|
||||
|
||||
### 3.6 Binary Encoding
|
||||
|
||||
The binary encoding is the **runtime and network** representation. It is compact
|
||||
and byte-stable. It uses a simple, explicitly-specified layout (no external
|
||||
serialization library) so it can be produced and consumed identically by the
|
||||
Godot client (GDScript) and the Python backend.
|
||||
|
||||
#### 3.6.1 Header
|
||||
|
||||
| Offset | Size | Field | Type / Encoding |
|
||||
|--------|------|--------------|------------------------------------------|
|
||||
| 0 | 4 | magic | ASCII `"AGPC"` (0x41 0x47 0x50 0x43) |
|
||||
| 4 | 2 | version | `uint16` LE (currently `1`) |
|
||||
| 6 | 2 | header_len | `uint16` LE (bytes of header after this) |
|
||||
| 8 | 4 | flags | `uint32` LE (bitmask, reserved) |
|
||||
| 12 | 4 | payload_len | `uint32` LE (bytes of payload body) |
|
||||
| 16 | 32 | checksum | SHA-256 of payload body (hex, 32 bytes) |
|
||||
|
||||
Total header size: **48 bytes**.
|
||||
|
||||
#### 3.6.2 Payload Body
|
||||
|
||||
The payload body is a sequence of typed sections. Each section has a small
|
||||
header:
|
||||
|
||||
| Offset | Size | Field | Type / Encoding |
|
||||
|--------|------|------------|----------------------------|
|
||||
| 0 | 1 | section_id | `uint8` (see table below) |
|
||||
| 1 | 4 | section_len| `uint32` LE (bytes of section data) |
|
||||
| 5 | ... | data | section-specific |
|
||||
|
||||
Section IDs:
|
||||
|
||||
| section_id | Section | Data layout |
|
||||
|------------|----------------|-------------------------------------------------------------------|
|
||||
| `0x01` | metadata | world_id, room_id (length-prefixed strings), coord (3×int32), bounds (6×float32) |
|
||||
| `0x02` | tile layer | name, layer_id, dims (3×uint16), palette, dense tile indices |
|
||||
| `0x03` | object | one `WorldObject` (repeated; one section per object) |
|
||||
| `0x04` | content flags | category severities (8×uint8), mature (uint8), sources (string list) |
|
||||
| `0x05` | meta | created_at, updated_at (int64 unix), revision (uint32), author (string) |
|
||||
|
||||
**String encoding:** length-prefixed UTF-8 — `uint16` LE byte length followed by
|
||||
the UTF-8 bytes.
|
||||
|
||||
**Tile layer data layout (section `0x02`):**
|
||||
|
||||
```
|
||||
name : string
|
||||
layer_id : uint16 LE
|
||||
width : uint16 LE
|
||||
height : uint16 LE
|
||||
depth : uint16 LE
|
||||
palette_count : uint16 LE
|
||||
palette : palette_count × TileDef
|
||||
tile_count : uint32 LE
|
||||
tiles : tile_count × uint16 LE (dense, row-major)
|
||||
```
|
||||
|
||||
```
|
||||
TileDef:
|
||||
id : uint16 LE
|
||||
asset_id : string
|
||||
solid : uint8
|
||||
flags : uint32 LE
|
||||
variants : uint8
|
||||
```
|
||||
|
||||
**Object data layout (section `0x03`):**
|
||||
|
||||
```
|
||||
id : string
|
||||
type : string
|
||||
asset_id : string
|
||||
pos : 3 × float32
|
||||
rot : 4 × float32
|
||||
scale : 3 × float32
|
||||
dynamic : uint8
|
||||
properties : JSON string (length-prefixed)
|
||||
flags : ContentFlags (see 0x04 layout)
|
||||
```
|
||||
|
||||
**Content flags layout (section `0x04`):**
|
||||
|
||||
```
|
||||
violence, sexual, language, substance, gambling, horror, hate, custom
|
||||
: 8 × uint8 (severity enum: 0=none,1=mild,2=moderate,3=severe)
|
||||
mature : uint8
|
||||
source_count: uint16 LE
|
||||
sources : source_count × string
|
||||
```
|
||||
|
||||
#### 3.6.3 Byte-Stability
|
||||
|
||||
For a given logical payload, the binary encoding is **deterministic**:
|
||||
|
||||
- All integers are little-endian.
|
||||
- All strings are UTF-8, length-prefixed, and never null-terminated.
|
||||
- Maps (e.g. `properties`) are serialized as a **canonical JSON string** with
|
||||
keys sorted lexicographically.
|
||||
- The `checksum` is the SHA-256 of the payload body bytes.
|
||||
|
||||
This guarantees that two encoders produce identical bytes, enabling content
|
||||
addressing, caching, and reproducible tests.
|
||||
|
||||
---
|
||||
|
||||
## 4. SQLite Persistence Schema
|
||||
|
||||
The server persists world state in a **SQLite** database. SQLite is chosen for
|
||||
its zero-configuration, single-file, transactional, and embedded nature — ideal
|
||||
for a server that owns the world store and needs ACID guarantees without a
|
||||
separate database process.
|
||||
|
||||
### 4.1 Database Layout
|
||||
|
||||
The database file is `world.db` (path configurable). It contains the following
|
||||
tables:
|
||||
|
||||
```
|
||||
worlds
|
||||
rooms
|
||||
chunks
|
||||
chunk_objects
|
||||
content_flags
|
||||
revisions
|
||||
```
|
||||
|
||||
### 4.2 `worlds`
|
||||
|
||||
Top-level world containers.
|
||||
|
||||
```sql
|
||||
CREATE TABLE worlds (
|
||||
id TEXT PRIMARY KEY, -- e.g. 'w_0001'
|
||||
name TEXT NOT NULL,
|
||||
description TEXT,
|
||||
chunk_size_x INTEGER NOT NULL DEFAULT 32,
|
||||
chunk_size_y INTEGER NOT NULL DEFAULT 32,
|
||||
chunk_size_z INTEGER NOT NULL DEFAULT 1,
|
||||
origin_x REAL NOT NULL DEFAULT 0,
|
||||
origin_y REAL NOT NULL DEFAULT 0,
|
||||
origin_z REAL NOT NULL DEFAULT 0,
|
||||
created_at TEXT NOT NULL, -- ISO-8601 UTC
|
||||
updated_at TEXT NOT NULL
|
||||
);
|
||||
```
|
||||
|
||||
### 4.3 `rooms`
|
||||
|
||||
Rooms within a world.
|
||||
|
||||
```sql
|
||||
CREATE TABLE rooms (
|
||||
id TEXT PRIMARY KEY, -- e.g. 'r_0001'
|
||||
world_id TEXT NOT NULL REFERENCES worlds(id) ON DELETE CASCADE,
|
||||
name TEXT NOT NULL,
|
||||
bounds_min_x REAL NOT NULL,
|
||||
bounds_min_y REAL NOT NULL,
|
||||
bounds_min_z REAL NOT NULL DEFAULT 0,
|
||||
bounds_max_x REAL NOT NULL,
|
||||
bounds_max_y REAL NOT NULL,
|
||||
bounds_max_z REAL NOT NULL DEFAULT 1,
|
||||
created_at TEXT NOT NULL,
|
||||
updated_at TEXT NOT NULL,
|
||||
UNIQUE (world_id, name)
|
||||
);
|
||||
CREATE INDEX idx_rooms_world ON rooms(world_id);
|
||||
```
|
||||
|
||||
### 4.4 `chunks`
|
||||
|
||||
The core persistence table. One row per chunk. The **payload** is stored as a
|
||||
BLOB in the **binary format** (§3.6); the JSON form is derived on demand for
|
||||
authoring/debugging and is not stored (to avoid dual-write drift).
|
||||
|
||||
```sql
|
||||
CREATE TABLE chunks (
|
||||
key TEXT PRIMARY KEY, -- canonical key 'world:room:cx:cy:cz'
|
||||
world_id TEXT NOT NULL REFERENCES worlds(id) ON DELETE CASCADE,
|
||||
room_id TEXT NOT NULL REFERENCES rooms(id) ON DELETE CASCADE,
|
||||
cx INTEGER NOT NULL,
|
||||
cy INTEGER NOT NULL,
|
||||
cz INTEGER NOT NULL DEFAULT 0,
|
||||
format_version INTEGER NOT NULL DEFAULT 1,
|
||||
payload BLOB NOT NULL, -- binary chunk encoding (§3.6)
|
||||
payload_len INTEGER NOT NULL,
|
||||
checksum TEXT NOT NULL, -- SHA-256 of payload
|
||||
revision INTEGER NOT NULL DEFAULT 0,
|
||||
dirty INTEGER NOT NULL DEFAULT 0, -- 1 = needs flush to disk
|
||||
created_at TEXT NOT NULL,
|
||||
updated_at TEXT NOT NULL,
|
||||
UNIQUE (world_id, room_id, cx, cy, cz)
|
||||
);
|
||||
CREATE INDEX idx_chunks_world_room ON chunks(world_id, room_id);
|
||||
CREATE INDEX idx_chunks_coord ON chunks(cx, cy, cz);
|
||||
```
|
||||
|
||||
**Design notes:**
|
||||
|
||||
- The `payload` BLOB is the single source of truth for chunk content. The
|
||||
`checksum` guards against corruption and enables content addressing.
|
||||
- `revision` increments on every write; it is used for optimistic concurrency
|
||||
and change detection (see §5.4).
|
||||
- `dirty` marks chunks that have been modified in memory but not yet flushed,
|
||||
enabling a write-behind persistence strategy (see §5.5).
|
||||
|
||||
### 4.5 `chunk_objects`
|
||||
|
||||
A denormalized, queryable index of the objects inside each chunk. This is
|
||||
**derived** from the chunk payload and kept in sync by the write path. It exists
|
||||
so the server can answer queries like "which chunks contain a door?" without
|
||||
parsing every payload BLOB.
|
||||
|
||||
```sql
|
||||
CREATE TABLE chunk_objects (
|
||||
id TEXT NOT NULL, -- object id (unique within chunk)
|
||||
chunk_key TEXT NOT NULL REFERENCES chunks(key) ON DELETE CASCADE,
|
||||
type TEXT NOT NULL, -- 'prop', 'interactable', ...
|
||||
asset_id TEXT,
|
||||
dynamic INTEGER NOT NULL DEFAULT 0,
|
||||
pos_x REAL NOT NULL,
|
||||
pos_y REAL NOT NULL,
|
||||
pos_z REAL NOT NULL DEFAULT 0,
|
||||
PRIMARY KEY (chunk_key, id)
|
||||
);
|
||||
CREATE INDEX idx_chunk_objects_type ON chunk_objects(type);
|
||||
CREATE INDEX idx_chunk_objects_asset ON chunk_objects(asset_id);
|
||||
```
|
||||
|
||||
**Sync mechanism:** `chunk_objects` is maintained **explicitly by the write
|
||||
path** — it is not a SQL trigger. Whenever `put_chunk` (or `delete_chunk`)
|
||||
commits a chunk, the service layer performs a **delete-and-reinsert** of that
|
||||
chunk's object rows in the same transaction: it deletes all rows for
|
||||
`chunk_key`, then inserts fresh rows parsed from the new payload. This keeps the
|
||||
index transactionally consistent with the payload and avoids the complexity and
|
||||
fragility of SQL triggers over a binary BLOB. Because the index is derived, it
|
||||
can always be rebuilt from `chunks.payload` if it ever drifts (a `rebuild_index`
|
||||
utility is provided for this).
|
||||
|
||||
### 4.6 `content_flags`
|
||||
|
||||
Persists the aggregated moderation flags per chunk (and optionally per object).
|
||||
This lets the server enforce age/content gates at load time without parsing
|
||||
payloads.
|
||||
|
||||
```sql
|
||||
CREATE TABLE content_flags (
|
||||
chunk_key TEXT NOT NULL REFERENCES chunks(key) ON DELETE CASCADE,
|
||||
object_id TEXT NOT NULL DEFAULT '', -- '' = chunk-level flag (sentinel)
|
||||
violence INTEGER NOT NULL DEFAULT 0,
|
||||
sexual INTEGER NOT NULL DEFAULT 0,
|
||||
language INTEGER NOT NULL DEFAULT 0,
|
||||
substance INTEGER NOT NULL DEFAULT 0,
|
||||
gambling INTEGER NOT NULL DEFAULT 0,
|
||||
horror INTEGER NOT NULL DEFAULT 0,
|
||||
hate INTEGER NOT NULL DEFAULT 0,
|
||||
custom INTEGER NOT NULL DEFAULT 0,
|
||||
mature INTEGER NOT NULL DEFAULT 0,
|
||||
sources TEXT NOT NULL DEFAULT '[]', -- JSON array of flag ids
|
||||
PRIMARY KEY (chunk_key, object_id)
|
||||
);
|
||||
CREATE INDEX idx_content_flags_mature ON content_flags(mature);
|
||||
```
|
||||
|
||||
Severity is stored as `0=none, 1=mild, 2=moderate, 3=severe`.
|
||||
|
||||
**Chunk-level vs. object-level flags:** Chunk-level flags use the **sentinel
|
||||
value `''` (empty string)** in `object_id` rather than `NULL`. This is
|
||||
deliberate: in SQLite, `NULL` values in a composite primary key are **not**
|
||||
unique-constrained, so two rows with the same `chunk_key` and `object_id = NULL`
|
||||
could be inserted accidentally. Using `''` as the sentinel means the composite
|
||||
`PRIMARY KEY (chunk_key, object_id)` enforces that there is **exactly one**
|
||||
chunk-level flag row per chunk. Object-level flags use the object's actual `id`
|
||||
(which is never empty). The application layer treats `object_id = ''` as
|
||||
"chunk-level" and any non-empty value as "object-level".
|
||||
|
||||
### 4.7 `revisions`
|
||||
|
||||
An append-only audit log of chunk writes. Enables rollback, auditing, and
|
||||
replication of changes.
|
||||
|
||||
```sql
|
||||
CREATE TABLE revisions (
|
||||
id INTEGER PRIMARY KEY AUTOINCREMENT,
|
||||
chunk_key TEXT NOT NULL, -- NOT a FK: survives chunk deletion
|
||||
revision INTEGER NOT NULL,
|
||||
actor TEXT NOT NULL, -- user / agent id
|
||||
action TEXT NOT NULL, -- 'create' | 'update' | 'delete'
|
||||
checksum TEXT NOT NULL, -- SHA-256 of payload
|
||||
payload BLOB, -- full binary payload at this revision
|
||||
created_at TEXT NOT NULL
|
||||
);
|
||||
CREATE INDEX idx_revisions_chunk ON revisions(chunk_key);
|
||||
```
|
||||
|
||||
**Rollback support:** The `payload` BLOB stores the **full binary chunk payload**
|
||||
at each revision. This is what makes rollback possible: to restore a chunk to a
|
||||
previous revision, the server reads the `payload` of the target revision and
|
||||
writes it back to `chunks.payload` (incrementing `revision` and appending a new
|
||||
`revisions` row). Without the payload, only the checksum would be available,
|
||||
which is insufficient to reconstruct the chunk.
|
||||
|
||||
**Audit trail preservation:** `chunk_key` is **not** a foreign key to `chunks`.
|
||||
This means deleting a chunk does **not** cascade-delete its revision history —
|
||||
the audit trail is preserved even after a chunk is removed. (The `chunk_key`
|
||||
string is still stored so the history can be correlated to a chunk that existed
|
||||
at that time.) If a chunk is later recreated with the same key, its history is
|
||||
still intact.
|
||||
|
||||
### 4.8 Schema Versioning & Migrations
|
||||
|
||||
The database carries a schema version in a `meta` table:
|
||||
|
||||
```sql
|
||||
CREATE TABLE meta (
|
||||
key TEXT PRIMARY KEY,
|
||||
value TEXT NOT NULL
|
||||
);
|
||||
-- seed: INSERT INTO meta(key, value) VALUES ('schema_version', '1');
|
||||
```
|
||||
|
||||
Migrations are applied in order at startup. Each migration is a numbered SQL
|
||||
script; the server tracks the applied version in `meta` and applies any pending
|
||||
migrations transactionally. This keeps the schema forward-compatible as the
|
||||
chunk format evolves.
|
||||
|
||||
---
|
||||
|
||||
## 5. Read/Write API
|
||||
|
||||
The API is exposed as a **Python service layer** on the backend (the same
|
||||
process that owns the SQLite store) and consumed by the Godot client over the
|
||||
network transport (see `networking.md`). The service layer is the **only**
|
||||
writer to the database; clients never touch SQLite directly.
|
||||
|
||||
### 5.1 Service Interface (Python)
|
||||
|
||||
```python
|
||||
class WorldStore:
|
||||
"""Owns the SQLite connection and chunk read/write operations."""
|
||||
|
||||
def get_chunk(self, key: str) -> Chunk | None: ...
|
||||
def get_chunk_binary(self, key: str) -> bytes | None: ...
|
||||
def put_chunk(self, chunk: Chunk, actor: str) -> Chunk: ...
|
||||
def delete_chunk(self, key: str, actor: str) -> None: ...
|
||||
def list_chunks(self, world_id: str, room_id: str | None = None,
|
||||
bounds: Bounds | None = None) -> list[str]: ...
|
||||
def get_chunk_flags(self, key: str) -> ContentFlags: ...
|
||||
def flush_dirty(self) -> int: ...
|
||||
def rollback_chunk(self, key: str, revision: int, actor: str) -> Chunk: ...
|
||||
def rebuild_index(self, chunk_key: str | None = None) -> int: ...
|
||||
def migrate(self) -> None: ...
|
||||
```
|
||||
|
||||
### 5.2 Encoding Helpers
|
||||
|
||||
The service layer provides symmetric encode/decode functions shared by the
|
||||
client and server:
|
||||
|
||||
```python
|
||||
def encode_binary(chunk: Chunk) -> bytes: ...
|
||||
def decode_binary(data: bytes) -> Chunk: ...
|
||||
def encode_json(chunk: Chunk) -> str: ...
|
||||
def decode_json(text: str) -> Chunk: ...
|
||||
def checksum(payload: bytes) -> str: ...
|
||||
```
|
||||
|
||||
These are the single implementation of the format spec (§3), so the Godot
|
||||
client and Python backend never drift.
|
||||
|
||||
### 5.3 Network RPCs
|
||||
|
||||
The chunk API is exposed to the client via RPCs (matching the networking
|
||||
architecture). All chunk traffic is **reliable** (chunks are discrete,
|
||||
must-arrive data).
|
||||
|
||||
| RPC | Direction | Payload | Notes |
|
||||
|----------------------------|-----------|-------------------------------------------|-------|
|
||||
| `request_chunk` | C → S | `{ key }` | Client asks for a chunk |
|
||||
| `chunk_data` | S → C | `{ key, binary_payload, checksum }` | Server streams a chunk |
|
||||
| `request_chunk_edit` | C → S | `{ key, base_revision, delta }` | Client submits an edit |
|
||||
| `chunk_edit_result` | S → C | `{ key, success, new_revision, error? }` | Acknowledges an edit |
|
||||
| `chunk_invalidated` | S → C | `{ key, new_revision }` | Server pushes a change |
|
||||
| `request_chunk_flags` | C → S | `{ key }` | Age/content gate check |
|
||||
|
||||
### 5.4 Edit & Concurrency Model
|
||||
|
||||
- **Read:** Client requests a chunk; server returns the binary payload and its
|
||||
`revision`.
|
||||
- **Edit:** Client submits a **delta** against a known `base_revision`. The
|
||||
server applies the delta, increments `revision`, persists, and returns the new
|
||||
revision.
|
||||
- **Optimistic concurrency:** If the chunk's current revision differs from the
|
||||
client's `base_revision`, the server rejects the edit with a conflict error
|
||||
and the client re-fetches and re-applies. This prevents lost updates when two
|
||||
clients edit the same chunk.
|
||||
- **Deltas:** A delta is a JSON patch (RFC 6902 style) applied to the chunk's
|
||||
logical model. The server validates the patched chunk (schema, bounds,
|
||||
moderation) before persisting.
|
||||
|
||||
### 5.5 Write-Behind Persistence
|
||||
|
||||
To amortize disk I/O, the server keeps a **dirty set** of chunks modified in
|
||||
memory and flushes them to SQLite in batches:
|
||||
|
||||
1. `put_chunk` updates the in-memory chunk and marks it `dirty`.
|
||||
2. A background flusher periodically calls `flush_dirty()`, which writes all
|
||||
dirty chunks in a single transaction and clears the `dirty` flag.
|
||||
3. On graceful shutdown, `flush_dirty()` is called to ensure durability.
|
||||
|
||||
This keeps the hot path (in-memory chunk access) fast while guaranteeing
|
||||
durability at shutdown and on a configurable interval.
|
||||
|
||||
**Recovery after unclean shutdown:** The `dirty` column in the `chunks` table
|
||||
exists specifically to support recovery if the process crashes before a flush
|
||||
completes. On startup, the server scans for rows where `dirty = 1` and treats
|
||||
them as **unflushed in-memory state that was lost** — it re-reads the last
|
||||
persisted payload from `chunks.payload` (the last durable state) and clears the
|
||||
`dirty` flag. In other words, `dirty = 1` at startup means "the last write was
|
||||
not durable; discard the in-memory delta and fall back to the persisted
|
||||
payload." This guarantees that the on-disk state is always a consistent,
|
||||
previously-committed snapshot, never a partially-written chunk. (The in-memory
|
||||
dirty set is authoritative during normal operation; the `dirty` column is only a
|
||||
recovery marker.)
|
||||
|
||||
### 5.6 Streaming & Caching
|
||||
|
||||
- The server streams only the chunks a client needs (those within the client's
|
||||
view radius), using `list_chunks` with a bounds query.
|
||||
- Chunks are cached in memory (LRU) keyed by `key`; the cache is invalidated on
|
||||
write.
|
||||
- The binary payload is content-addressed by `checksum`, so unchanged chunks can
|
||||
be served from cache without re-reading SQLite.
|
||||
|
||||
---
|
||||
|
||||
## 6. Format Versioning & Migration
|
||||
|
||||
- The chunk format `version` field (currently `1`) is checked on decode. A
|
||||
decoder that encounters a higher version than it supports **rejects** the
|
||||
chunk with a clear error rather than misreading it.
|
||||
- The SQLite `schema_version` in `meta` drives database migrations (§4.8).
|
||||
- Chunk payloads are migrated **lazily**: when a chunk is read and its
|
||||
`format_version` is older than the current one, the server migrates it to the
|
||||
current version in memory and marks it dirty so it is rewritten on the next
|
||||
flush. This avoids a costly full-world migration at startup.
|
||||
|
||||
---
|
||||
|
||||
## 7. Security & Integrity
|
||||
|
||||
- **Server-authoritative writes:** Only the `WorldStore` writes to SQLite;
|
||||
clients submit deltas that are validated before application.
|
||||
- **Checksum verification:** Every chunk payload is checksummed (SHA-256) on
|
||||
write and verified on read. Corruption is detected and the chunk is re-fetched
|
||||
or flagged.
|
||||
- **Bounds validation:** Chunk coordinates and object positions are validated
|
||||
against the world's chunk dimensions and room bounds before persistence.
|
||||
- **Moderation enforcement:** `content_flags` are checked at load time; mature
|
||||
chunks are gated behind the age-verification flow (see `content_moderation.md`).
|
||||
- **Input validation:** All string fields are length-limited and validated
|
||||
against allowed character sets to prevent injection and oversized payloads.
|
||||
|
||||
---
|
||||
|
||||
## 8. Open Questions / Future Work
|
||||
|
||||
- **Volumetric worlds:** The schema and format already support `CHUNK_SIZE_Z >
|
||||
1`, but the tooling and streaming for 3D chunks are not yet specified.
|
||||
- **Chunk compression:** For very large worlds, the binary payload could be
|
||||
compressed (e.g. zstd) before storage/transfer. The header reserves a `flags`
|
||||
bitmask for a compression flag.
|
||||
- **Multi-server sharding:** If a single SQLite file becomes a bottleneck, the
|
||||
`chunks` table could be sharded by `world_id` across multiple databases. The
|
||||
key design already supports this (world_id is a leading key component).
|
||||
- **Delta compression for streaming:** Instead of sending full chunks, the
|
||||
server could send only the delta between revisions to reduce bandwidth for
|
||||
frequently-updated chunks.
|
||||
@@ -0,0 +1,24 @@
|
||||
; Engine configuration file.
|
||||
; It's best edited using the editor UI and not directly,
|
||||
; but it can also be edited by hand.
|
||||
|
||||
config_version=5
|
||||
|
||||
[application]
|
||||
|
||||
config/name="AGP-Game"
|
||||
run/main_scene="res://scenes/main_menu.tscn"
|
||||
config/features=PackedStringArray("4.6.2")
|
||||
|
||||
[autoload]
|
||||
|
||||
[display]
|
||||
|
||||
window/size/viewport_width=1920
|
||||
window/size/viewport_height=1080
|
||||
window/stretch/mode="canvas_items"
|
||||
|
||||
[rendering]
|
||||
|
||||
renderer/rendering_method="gl_compatibility"
|
||||
renderer/rendering_method.mobile="gl_compatibility"
|
||||
@@ -0,0 +1,43 @@
|
||||
[gd_scene load_steps=2 format=3]
|
||||
|
||||
[ext_resource type="Script" path="res://scripts/main_menu.gd" id="1_main"]
|
||||
|
||||
[node name="MainMenu" type="Control"]
|
||||
anchors_preset = 15
|
||||
anchor_right = 1.0
|
||||
anchor_bottom = 1.0
|
||||
grow_horizontal = 2
|
||||
grow_vertical = 2
|
||||
script = ExtResource("1_main")
|
||||
|
||||
[node name="CenterContainer" type="CenterContainer" parent="."]
|
||||
layout_mode = 3
|
||||
anchors_preset = 15
|
||||
anchor_right = 1.0
|
||||
anchor_bottom = 1.0
|
||||
grow_horizontal = 2
|
||||
grow_vertical = 2
|
||||
|
||||
[node name="VBoxContainer" type="VBoxContainer" parent="CenterContainer"]
|
||||
layout_mode = 1
|
||||
theme_override_constants/separation = 16
|
||||
size_flags_horizontal = 4
|
||||
|
||||
[node name="TitleLabel" type="Label" parent="CenterContainer/VBoxContainer"]
|
||||
layout_mode = 1
|
||||
text = "AGP Game"
|
||||
horizontal_alignment = 1
|
||||
theme_override_font_sizes/font_size = 72
|
||||
|
||||
[node name="PlayButton" type="Button" parent="CenterContainer/VBoxContainer"]
|
||||
layout_mode = 1
|
||||
text = "Play"
|
||||
size_flags_horizontal = 4
|
||||
|
||||
[node name="QuitButton" type="Button" parent="CenterContainer/VBoxContainer"]
|
||||
layout_mode = 1
|
||||
text = "Quit"
|
||||
size_flags_horizontal = 4
|
||||
|
||||
[connection signal="pressed" from="CenterContainer/VBoxContainer/PlayButton" to="." method="_on_play_button_pressed"]
|
||||
[connection signal="pressed" from="CenterContainer/VBoxContainer/QuitButton" to="." method="_on_quit_button_pressed"]
|
||||
@@ -0,0 +1,14 @@
|
||||
extends Control
|
||||
|
||||
|
||||
func _ready():
|
||||
pass
|
||||
|
||||
|
||||
func _on_play_button_pressed():
|
||||
# No gameplay scene exists yet — wire this to the real scene once one lands.
|
||||
print("Play pressed — no gameplay scene yet")
|
||||
|
||||
|
||||
func _on_quit_button_pressed():
|
||||
get_tree().quit()
|
||||
Reference in New Issue
Block a user