Royalty implementation for NFTs. https://www.youtube.com/watch?v=h6Fb_dPZCd0

ERC2981NFTCustom.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.2;

import "@openzeppelin/contracts@4.4.2/token/ERC721/ERC721.sol";
import "@openzeppelin/contracts@4.4.2/token/ERC721/extensions/ERC721Enumerable.sol";
import "@openzeppelin/contracts@4.4.2/access/Ownable.sol";


contract MyToken is ERC721, ERC721Enumerable, Ownable {
    string public contractURI;
    uint96 royaltyFeesInBips;
    address royaltyAddress;

    constructor(uint96 _royaltyFeesInBips, string memory _contractURI) ERC721("MyToken", "MTK") {
        royaltyFeesInBips = _royaltyFeesInBips;
        royaltyAddress = owner();
        contractURI = _contractURI;
        // setRoyaltyInfo(msg.sender, _royaltyFeesInBips);
    }

    function safeMint(address to, uint256 tokenId) public onlyOwner {
        _safeMint(to, tokenId);
    }

    function setRoyaltyInfo(address _receiver, uint96 _royaltyFeesInBips) public onlyOwner {
        royaltyAddress = _receiver;
        royaltyFeesInBips = _royaltyFeesInBips;
    }

    function setContractURI(string calldata _contractURI) public onlyOwner {
        contractURI = _contractURI;
    }

    // The following functions are overrides required by Solidity.
    function _beforeTokenTransfer(address from, address to, uint256 tokenId)
        internal
        override(ERC721, ERC721Enumerable)
    {
        super._beforeTokenTransfer(from, to, tokenId);
    }

    function royaltyInfo(uint256 _tokenId, uint256 _salePrice)
        external
        view
        virtual
        override
        returns (address, uint256)
    {
        return (royaltyAddress, calculateRoyalty(_salePrice));
    }

    function calculateRoyalty(uint256 _salePrice) pure public returns (uint256) {
        return (_salePrice / 10000) * royaltyFeesInBips;
    }

    function supportsInterface(bytes4 interfaceId)
            public
            view
            override(ERC721, ERC721Enumerable)
            returns (bool)
    {
        return interfaceId == 0x2a55205a || super.supportsInterface(interfaceId);
    }
}

ERC2981NFTOZ.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.2;

import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/common/ERC2981.sol";
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC721/ERC721.sol";
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC721/extensions/ERC721Enumerable.sol";
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/access/Ownable.sol";


contract MyToken is ERC721, ERC721Enumerable, ERC2981, Ownable {
    string public contractURI;

    constructor(uint256 _royaltyFeesInBips, string memory _contractURI) ERC721("MyToken", "MTK") {
        setRoyaltyInfo(owner(), _royaltyFeesInBips);
        contractURI = _contractURI;
    }

    function safeMint(address to, uint256 tokenId) public onlyOwner {
        _safeMint(to, tokenId);
    }

    function setRoyaltyInfo(address _receiver, uint96 _royaltyFeesInBips) public onlyOwner {
        _setDefaultRoyalty(_receiver, _royaltyFeesInBips);
    }

    function setContractURI(string calldata _contractURI) public onlyOwner {
        contractURI = _contractURI;
    }

    // The following functions are overrides required by Solidity.

    function _beforeTokenTransfer(address from, address to, uint256 tokenId)
        internal
        override(ERC721, ERC721Enumerable)
    {
        super._beforeTokenTransfer(from, to, tokenId);
    }

    function supportsInterface(bytes4 interfaceId)
        public
        view
        override(ERC721, ERC721Enumerable, ERC2981)
        returns (bool)
    {
        return super.supportsInterface(interfaceId);
    }
}

_setDefaultRoyalty takes a uint96 for the second argument so i think line 22 needs to change _royaltyFeesInBips to uint96 from uint256

@arkaydeus good catch, fixed it, thanks!

Line 60 of the first example above has an extra ) at the end than there should be.

what the difference between both of the contracts?

get at ERC2981NFTCustom.sol
can someone please help
an error:

DeclarationError: Function with same name and parameter types defined twice.
--> contracts/ERC2981NFTdrawo.sol:43:5:
|
43 | function supportsInterface(bytes4 interfaceId)
| ^ (Relevant source part starts here and spans across multiple lines).
Note: Other declaration is here:
--> contracts/ERC2981NFTdrawo.sol:67:5:
|
67 | function supportsInterface(bytes4 interfaceId)
| ^ (Relevant source part starts here and spans across multiple lines).

TypeError: Function has override specified but does not override anything.
--> contracts/ERC2981NFTdrawo.sol:57:9:
|
57 | override
| ^^^^^^^^

@logistic-people-deutschland on ERC2981NFTCustom.sol file there are supportsInterface function twice, so remove it the last one and should work

what the difference between both of the contracts?

@Nir-Cohen one uses Openzeppelin's implementation and one is custom. Accompanying video - https://www.youtube.com/watch?v=h6Fb_dPZCd0

Hi, sir. I have add setRoyaltyInfo to my ERC2981 contract, but it doesn't work.

contract ALPHA is ERC721Enumerable, ERC2981, Ownable{
constructor()
ERC721("ALPHA Coin", "ALPHA")
{
manager = msg.sender;
// set royalty of all NFTs to 10%
_setDefaultRoyalty(manager, 1000);
}
}

sir, the Creator Fees doesn't show on test opensea, is that right?

line 13 on constructor _royaltyFeesInBips should be uint96

what about an ERC1155 implementation?

It should be uint96 on constructor too on second contract.

I am using the first file ERC2981NFTCustom.sol. This is still valid but please help if you can fix this error.