CustomNFTFunctionality.md

Changing the behavior of your NFT

Solidity supports inheritance, so instead of tampering with the NFT contracts that come with Shipyard directly, you'll create a new contract and have it inherit from one of the existing contracts. See Solidity by Example and GeeksForGeeks for more info on inheritance. The practical takeway is:

• Make a new file in src/ called MyVeryOwnNFT.sol
• Import shipyard-core/reference/AbstractNFT.sol: and inherit from it (contract MyVeryOwnNFT is AbstractNFT { ...)
• Override some functions (name, symbol, and tokenURI are good starting places, e.g. function name() public pure override returns (string memory) { ...)
• Add some other fun stuff if you want to

And you'll end up with something that might look like Dockmaster, but with your own special touches.

(You'll notice that Dockmaster itself looks a lot like shipyard-core's ExampleNFT.sol, but it's special to me now, because I've made changes!)

What's great about this inheritance pattern is that the ERC721ConduitPreapproved_Solady we inheritied via AbstractNFT has already handled all the routine ERC721 functionality for us in an almost comically optimized way. So we can burn calories on making something cool, instead of reinventing the nonfungible token wheel. But when someone calls the ownerOf function on my contract, it's going to work as expected.

And because I inherited AbstractNFT, which itself inherit OnchainTraits, I automatically get functionality that lets me manage on chain traits. So, now I want to add the following trait to token ID 1:

{
  "trait_type": "Dock Material"
  "value": "Aluminum"
}

To accomplish that, I'll need to first set a trait label by calling setTraitLabel with bytes32(uint256(0x6d6174657269616c)) (the bytes encoded version of "material") as the traitKey and the following struct as the TraitLabel arg:

TraitLabel memory myFirstDynamicTrait {(
    fullTraitKey: myFirstTraitKeyString,
    traitLabel: myFirstLabelString,
    acceptableValues: myFirstArrayOfAcceptableValuesStrings,
    fullTraitValues: myFirstArrayOfFullTraitValues,
    displayType: myFirstDisplayTypeEnumValue,
    editors: myFirstEditorsValue;
)}

Look at TraitLabelLib.sol to get a better sense of how to set those values up.

Then I just call setTrait with bytes32(uint256(0x6d6174657269616c)) as the traitKey argument, 1 as the tokenID argument, and bytes32(uint256(<bytes32_value_of_my_trait>)) as the trait argument. The _setTrait function will store the value (_traits[tokenId][traitKey] = value;) and emit a TraitUpdated event, to put the world on notice that token ID 1 now has a new trait on it.

Now is the time to go wild. Make some wild generative art. Create a novel minting mechanic (only contract deployers are eligible?!). Build an AMM into it. Whatever idea brought you here in the first place, here's where you wire it up. Either bolt it on (like SayHiToMom) or override existing functionality (like tokenURI). Your NFT is as interesting as you make it.

Next up:

Deploying for real