ERC-2981

ERC2981

Git Source

Authors: Solady (https://github.com/vectorized/solady/blob/main/src/tokens/ERC2981.sol), Modified from OpenZeppelin (https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/common/ERC2981.sol), Ninfa.io removed unused code

Simple ERC2981 NFT Royalty Standard implementation.

State Variables

_ERC2981_MASTER_SLOT_SEED

*The default royalty info is given by:

let packed := sload(_ERC2981_MASTER_SLOT_SEED)
let receiver := shr(96, packed)
let royaltyFraction := xor(packed, shl(96, receiver))

The per token royalty info is given by.

mstore(0x00, tokenId)
mstore(0x20, _ERC2981_MASTER_SLOT_SEED)
let packed := sload(keccak256(0x00, 0x40))
let receiver := shr(96, packed)
let royaltyFraction := xor(packed, shl(96, receiver))
```*


```solidity
uint256 private constant _ERC2981_MASTER_SLOT_SEED = 0xaa4ec00224afccfdb7;

Functions

_feeDenominator

Checks that _feeDenominator is non-zero.

Returns the denominator for the royalty amount. Defaults to 10000, which represents fees in basis points. Override this function to return a custom amount if needed.

function _feeDenominator() internal pure returns (uint96);

royaltyInfo

Returns the receiver and royaltyAmount for tokenId sold at salePrice. It first attempts to read the per-token royalty information for the given tokenId by computing a storage slot using the tokenId and a predefined constant (_ERC2981_MASTER_SLOT_SEED). If no specific royalty information is found for the tokenId (i.e., the receiver address is zero), it then reads the default royalty information stored at the slot determined by _ERC2981_MASTER_SLOT_SEED directly.

function royaltyInfo(
    uint256 tokenId,
    uint256 salePrice
)
    public
    view
    returns (address receiver, uint256 royaltyAmount);

_setDefaultRoyalty

*Sets the default royalty receiver and feeNumerator. Sets the default royalty receiver and amount, which stores the information in a packed format in the slot determined by _ERC2981_MASTER_SLOT_SEED. This default royalty information is then used by the royaltyInfo function whenever a specific token does not have its royalty information set. Requirements:

• receiver must not be the zero address.

• feeNumerator must not be greater than the fee denominator.*

function _setDefaultRoyalty(address receiver, uint96 feeNumerator) internal;

_setTokenRoyalty

*Sets the royalty receiver and feeNumerator for tokenId. Requirements:

• receiver must not be the zero address.

• feeNumerator must not be greater than the fee denominator.*

function _setTokenRoyalty(uint256 tokenId, address receiver, uint96 feeNumerator) internal;

_resetTokenRoyalty

Sets the royalty receiver and feeNumerator for tokenId to zero.

function _resetTokenRoyalty(uint256 tokenId) internal;

Errors

RoyaltyOverflow

The royalty fee numerator exceeds the fee denominator.

error RoyaltyOverflow();

RoyaltyReceiverIsZeroAddress

The royalty receiver cannot be the zero address.

error RoyaltyReceiverIsZeroAddress();