> ## Documentation Index
> Fetch the complete documentation index at: https://docs.onchainbrews.wtf/llms.txt
> Use this file to discover all available pages before exploring further.

# Traits

> TL;DR for collectors: four layers, weighted RNG, deterministic per-auction seed, art and metadata hosted entirely on-chain—and new traits can drop anytime to keep the collection spicy.

### Trait Randomization

Traits can be **common, uncommon, rare, epic, or legendary**. For each category, we spin a deterministic on-chain wheel using the core contract’s per-auction seed.

* **Seed source:** `core.getAuctionSeed(auctionId)` returns a per‑auction seed derived in the core contract from chain data.
* `getTrait(category, auctionId)`**:**
  1. Sums `weight` across all traits in `category`.
  2. Computes `rand = H(category, auctionId, seed) % totalWeight`.
  3. Scans cumulatively over traits; the bucket where `rand < acc` is the selected **trait name**.
* Given the same `auctionId`and trait table, selection is reproducible across nodes and time. That means the artwork for an auction is **fixed** once the seed is set for a given auction in the core contract.

### Layer Retrieval

The same `auctionId` + same trait tables = **the same result forever**. Everyone renders the same art because everything about the brew lives on-chain.

* `getSVGFragment(category, traitName)`**:** Looks up the stored SVG fragment string for the named trait.
* `getTraits(auctionId)`**:** Convenience that resolves the selected trait **names** for each category in canonical order (`Background`, `Brew`, `Mug`, `Top`).

### SVG Composition (The Image Itself)

The renderer stitches the SVG, Base64-encodes it, and serves it inside the token’s `tokenURI` as a data URI—no IPFS pins to rot, no servers to trust. Metadata includes the four trait names so marketplaces can show attributes cleanly.

* `buildSVG(auctionId)`**:**
  1. Starts with an `<svg>` root sized `1080×1080`.
  2. For each category in `categories` order, resolves the chosen **name** with `getTrait` and fetches its **fragment** with `getSVGFragment`.
  3. Concatenates fragments in order to form a single SVG document.
  4. Appends the closing `</svg>` tag and returns the complete **image** string.

<Info>
  **Layering matters:** The array order is the z‑order. Background is written first, then Brew, then Mug, then Top.
</Info>

### Backgrounds

| **Name** | **Rarity** | **Weight** |
| -------- | ---------- | ---------- |
| Blue     | Common     |            |
| Pink     |            |            |
| Purple   |            |            |
| Black    |            |            |

### Brews

| **Name**    | **Rarity** | **Weight** |
| :---------- | :--------- | :--------- |
| Miner Lite  | Common     |            |
| Blockweiser |            |            |
| gweiness    |            |            |
| HOLDweisen  |            |            |
| Bandit IPA  |            |            |
| Juicy Brew  |            |            |
| Stoutoshi   |            |            |
| Slime       |            |            |

### Mugs

| **Name**    | **Rarity** | **Weight** |
| :---------- | :--------- | :--------- |
| Glass       | Common     |            |
| Ceramic     |            |            |
| Ice         |            |            |
| Wood        |            |            |
| Steel       |            |            |
| Charcoal    |            |            |
| Rose Gold   |            |            |
| Gold        |            |            |
| Holographic |            |            |
| Earth       |            |            |

### Tops

| **Name**      | **Rarity** | **Weight** |
| :------------ | :--------- | :--------- |
| Regular Foam  | Common     |            |
| Flat Foam     | Common     |            |
| Tall Foam     | Common     |            |
| Drippy Foam   |            |            |
| Igloo         |            |            |
| Fyre          |            |            |
| Duck          |            |            |
| Diamond       |            |            |
| Rain          |            |            |
| Red Trucker   |            |            |
| Green Trucker |            |            |
| Rainbow       |            |            |
| Poop          |            |            |
| Skull         |            |            |