Non-Fungible Tokens, or NFTs in short, have recently gained significant popularity due to the rising trend in the blockchain gaming space. Ever since their inception, NFTs became really popular among the crypto community, thanks to successful projects like Cryptokitties and CryptoPunks, etc.
Cryptokitties is one of the most hyped NFT projects within the DeFi and blockchain gaming space. CryptoKitties are digital, collectible cats built on the Ethereum blockchain, and they can be bought and sold using Ethereum, and bred to create new cats with several traits and varying characteristics.
CryptoKitties is basically a digital pet community centred around collecting, training, raising, and battling fantasy creatures that are known as ‘CryptoEnter’. Each CryptoEnter has unique genetic data stored on Opera.
A CryptoEnter can possess two different genes with different body parts. This smart contract serves as an example, and can be a good starting point for anyone who is looking to build NFT based products on the Enter blockchain platform.
Prerequisite
To Run these examples please follow the following steps:
This project is for test purpose only, it contains only the basic functions and minimum requirements.
run npm install to install dependencies
$ npm install
Contract: Game
✓ should NOT mint if not admin (47ms)
✓ should mint if admin (154ms)
✓ should NOT transfer if balance is 0 (104ms)
✓ should NOT transfer if not owner (79ms)
✓ safeTransferFrom() should NOT transfer if recipient contract does not implement erc721recipient interface (95ms)
✓ transferFrom() should transfer (70ms)
✓ transferFrom() should transfer (70ms)
✓ safeTransferFrom() should transfer (62ms)
✓ should transfer token when approved (117ms)
✓ should transfer token when approved (87ms)
Contract: Game
✓ should NOT mint if not admin
✓ should mint if admin (161ms)
✓ should breed (167ms)
13 passing (4s)
Deploy Locally and Interact with frontend
Start by running Ganache-CLI. It runs a personal Ethereum blockchain on which you can use to run tests, execute commands. Run this command:
You can either import the mnemonic into metamask or at least the first account (you should have the private key) into Metamask.
Then deploy our contract by running this command:
$ truffle migrate --network testrpc --reset
You should get this output:
Compiling your contracts...
===========================
✔ Fetching solc version list from solc-bin. Attempt #1
> Everything is up to date, there is nothing to compile.
Starting migrations...
======================
> Network name: 'testrpc'
> Network id: 1337
> Block gas limit: 6721975 (0x6691b7)
1_initial_migration.js
======================
Replacing 'Migrations'
----------------------
> transaction hash: 0x28099872c6feeceab4033e63e9a3c48e73f315e2c61feef4a5bf7ac947c3329e
> Blocks: 0 Seconds: 0
> contract address: 0xe78A0F7E598Cc8b0Bb87894B0F60dD2a88d6a8Ab
> block number: 1
> block timestamp: 1608736619
> account: 0x90F8bf6A479f320ead074411a4B0e7944Ea8c9C1
> balance: 99.99665588
> gas used: 167206 (0x28d26)
> gas price: 20 gwei
> value sent: 0 ETH
> total cost: 0.00334412 ETH
> Saving migration to chain.
> Saving artifacts
-------------------------------------
> Total cost: 0.00334412 ETH
2_deploy_contracts.js
=====================
Replacing 'CryptoEnter'
------------------------
> transaction hash: 0x8a3dd0bc5d57a8f6dcba777ded4b0a2038fe6f8c7c6684e8546cd49a40220a9d
> Blocks: 0 Seconds: 0
> contract address: 0xCfEB869F69431e42cdB54A4F4f105C19C080A601
> block number: 3
> block timestamp: 1608736619
> account: 0x90F8bf6A479f320ead074411a4B0e7944Ea8c9C1
> balance: 99.9661064
> gas used: 1485231 (0x16a9af)
> gas price: 20 gwei
> value sent: 0 ETH
> total cost: 0.02970462 ETH
> Saving migration to chain.
> Saving artifacts
-------------------------------------
> Total cost: 0.02970462 ETH
Summary
=======
> Total deployments: 2
> Final cost: 0.03304874 ETH
Then you can finally run:
$ npm run start
Compiled successfully!
You can now view app in the browser.
Local: http://localhost:3000/
On Your Network: http://192.168.102.7:3000/
Note that the development build is not optimized.
To create a production build, use npm run build.
Issues
You may encounter some problems with the current version of Metamask which does not detect the correct nonce, you can switch from network to Mainnet and then back to Local that solves most of the issues until a correction is made.
