ERC721Delegator is an interface extended from ERC721. With ERC721Delegator, ERC721 can be loaned and borrowed while the lender only has the right to use, but cannot transfer the assets.
Returns the delegator of an ERC721.
Attention: Delegator is only an attribute of ERC721 for identification, and does not have any direct permissions like {approve} {setApprovalForAll} {transferFrom} {safeTransferFrom}.
function delegatorOf(uint256 tokenId) external view returns (address);Set _delegator as the delegator of the ERC721 with tokenId as _tokenId.
Attention: The delegator attribute can be set to address(0), which means the ERC721 has no delegator.
function setDelegator(address _delegator, uint256 _tokenId) external returns (bool);see contracts/ERC721Delegator.sol
The developers of ERC721Delegator interface should strictly distinguish between owner and delegator from msg.sender. The delegator is always an attribute (like a tag) for identification, and does not hold or handle any related assets.
That means, use require(_onlyOwnerOrDelegator(tokenId)) instead of require(_onlyOwner(tokenId)) for identity verification of msg.sender . When it comes to the transfer of assets, the sender should be the owner (not delegator) or other (depending on your game logic), and when the assets are to be transferred out, the recipient should be the owner or other.
Warn: If there is an NFT burning function in the game logic, please make sure the caller is the owner, otherwise it may cause losses to the owner.
In the showcase, you can see how to handle the state changes of the game character, the asset transfer of ERC20, ERC721 when msg.sender is a delegator.