【区块链】从零开始写一个区块链游戏--水果机

机器环境

• win10
• nodev8.9.4
• npm install -g truffle
• npm install -g ganache-cli

Github地址

• https://github.com/ns2250225/ethereum-slot-machine

效果

初始化项目

• mkdir eth-slot-machine
• cd eth-slot-machine
• truffle init

编写游戏合约

• contracts/SlotMachine.sol

pragma solidity ^0.4.4;

contract SlotMachine {

    address public slotMachineFunds;

    uint256 public coinPrice = 0.1 ether;

    address owner;

    event Rolled(address sender, uint rand1, uint rand2, uint rand3);

    mapping (address => uint) pendingWithdrawals;

    modifier onlyOwner() {
        require(owner == msg.sender);
        _;
    }

    function SlotMachine() {
        owner = msg.sender;
    }

    //the user plays one roll of the machine putting in money for the win
    function oneRoll() payable {
        require(msg.value >= coinPrice);

        uint rand1 = randomGen(msg.value);
        uint rand2 = randomGen(msg.value + 10);
        uint rand3 = randomGen(msg.value + 20);

        uint result = calculatePrize(rand1, rand2, rand3);

        Rolled(msg.sender, rand1, rand2, rand3);

        pendingWithdrawals[msg.sender] += result;

    }

    function contractBalance() constant returns(uint) {
        return this.balance;
    }

    function calculatePrize(uint rand1, uint rand2, uint rand3) constant returns(uint) {
        if(rand1 == 5 && rand2 == 5 && rand3 == 5) {
            return coinPrice * 30;
        } else if (rand1 == 6 && rand2 == 5 && rand3 == 6) {
            return coinPrice * 20;
        } else if (rand1 == 4 && rand2 == 4 && rand3 == 4) {
            return coinPrice * 15;
        } else if (rand1 == 3 && rand2 == 3 && rand3 == 3) {
            return coinPrice * 12;
        } else if (rand1 == 2 && rand2 == 2 && rand3 == 2) {
            return coinPrice * 10;
        } else if (rand1 == 1 && rand2 == 1 && rand3 == 1) {
            return coinPrice * 5;
        } else if ((rand1 == rand2) || (rand1 == rand3) || (rand2 == rand3)) {
            return coinPrice;
        } else {
            return 0;
        }
    }

    function withdraw() {
        uint amount = pendingWithdrawals[msg.sender];

        pendingWithdrawals[msg.sender] = 0;

        msg.sender.transfer(amount);
    }

    function balanceOf(address user) constant returns(uint) {
        return pendingWithdrawals[user];
    }

    function setCoinPrice(uint _coinPrice) onlyOwner {
        coinPrice = _coinPrice;
    }

    function() onlyOwner payable {
    }

    function cashout(uint _amount) onlyOwner {
        msg.sender.transfer(_amount);
    }

    function randomGen(uint seed) private constant returns (uint randomNumber) {
        return (uint(sha3(block.blockhash(block.number-1), seed )) % 6) + 1;
    }

}

编写迁移脚本

• migrations/2_deploy_contracts.js

var SlotMachine = artifacts.require('./SlotMachine');

module.exports = (deployer) => {
    deployer.deploy(SlotMachine);
}

配置truffle.js文件

module.exports = {
  // See 
  // to customize your Truffle configuration!
  networks: {  
    development: {  
      host: "localhost",  
      port: 8545,  
      network_id: "*"  
    }  
  }  
};

启动ganache-cli

• ganache-cli
• 记录账号信息

迁移合约

• truffle migrate
• 记录下合约地址

启动前端

• npm install && npm run dev