Now that we have successfully developed the popular Rock-Paper-Scissors game for the TRON blockchain, let’s take on a new challenge and create an action-packed game – Zombie Survival.
ZombieSurvival is a smart contract game built on the TRON blockchain using the Solidity programming language. The game simulates a zombie apocalypse where each player is a survivor, and they can join the game, shoot zombies, acquire score, and acquire items and weapons to improve their chances of survival. Each player has an owner, health, ammo, and score. The contract has several functions that allow players to join the game, shoot zombies, acquire items, upgrade weapons, complete quests and more.
When a player joins the game, they are added to the mapping “players” as a struct Player with a default health, ammo and score. The player can then use the “shoot” function to try and hit the zombies, this function will check if the player’s health and ammo are greater than 0 and it will use the function “checkHit” to determine if the player hit the zombies or not. If the player hit the zombies, the player’s health will decrease by 10, if the player’s health reaches 0, the player’s stats will be reset.
The contract also has functions to acquire items, upgrade weapons, complete quests and trade with other players. The player can use the “acquireItem” function to purchase items using their score. The player can use the “upgradeWeapon” function to upgrade their weapon using their score. The player can use the “completeQuest” function to complete quests and earn rewards. The player can use the “trade” function to trade with other players using items.
The contract also emits events when a player shoots, when a player’s health changes and when a player’s score changes.
pragma solidity ^0.4.24;
contract ZombieSurvival {
//Struct to hold the information of a player
struct Player {
address owner;
uint health;
uint ammo;
uint score;
mapping(string => uint) inventory;
mapping(string => uint) upgrades;
}
//Mapping to hold all the players
mapping(address => Player) public players;
//Event to be emitted when player shoots a zombies
event Shoot(address shooter);
//Event to be emitted when player's health changes
event HealthChanged(address player, uint newHealth);
//Event to be emitted when player's score changes
event ScoreChanged(address player, uint newScore);
//Function to join the game
function joinGame() public {
require(players[msg.sender].owner == address(0));
players[msg.sender].owner = msg.sender;
players[msg.sender].health = 100;
players[msg.sender].ammo = 20;
players[msg.sender].score = 0;
}
//Function to shoot a zombies
function shoot() public {
require(players[msg.sender].health > 0);
require(players[msg.sender].ammo > 0);
//decrement ammo
players[msg.sender].ammo--;
//increment score
players[msg.sender].score++;
//check if the player hit a zombies
if (checkHit()) {
//decrement health
players[msg.sender].health -= 10;
emit HealthChanged(msg.sender, players[msg.sender].health);
checkDeath();
}
emit ScoreChanged(msg.sender, players[msg.sender].score);
emit Shoot(msg.sender);
}
//Function to acquire an item
function acquireItem(string _itemName) public {
require(players[msg.sender].score >= getItemCost(_itemName));
require(players[msg.sender].inventory[_itemName] == 0);
players[msg.sender].score -= getItemCost(_itemName);
players[msg.sender].inventory[_itemName]++;
}
//Function to upgrade a weapon
function upgradeWeapon(string _weaponName) public {
require(players[msg.sender].score >= getWeaponUpgradeCost(_weaponName));
uint currentLevel = getWeaponLevel(msg.sender, _weaponName);
require(currentLevel != 0);
require(currentLevel < maxWeaponLevel);
players[msg.sender].score -= getWeaponUpgradeCost(_weaponName);
players[msg.sender].upgrades[_weaponName]++;
}
//Function to complete a quest
function completeQuest(string _questName) public {
require(players[msg.sender].health > 0);
require(players[msg.sender].ammo > 0);
//check if the player completed the quest
if (checkQuestCompletion(_questName)) {
//increment score
players[msg.sender].score += getQuestReward(_questName);
//increment health
players[msg.sender].health += getQuestHealthReward(_questName);
//increment ammo
players[msg.sender].ammo += getQuestAmmoReward(_questName);
}
}
//Function to buy TRX from the shop
function buyTRX(uint _amount) public {
require(msg.sender.transfer(_amount));
}
//Function to sell TRX to the shop
function sellTRX(uint _amount) public payable {
require(msg.value == _amount);
}
//Function to check if the player completed a quest
function checkQuestCompletion(string _questName) private view returns (bool) {
uint random = uint(keccak256(abi.encodePacked(block.timestamp, block.difficulty))) % 2;
if (random == 1) return true;
else return false;
}
//Function to get the cost of an item
function getItemCost(string _itemName) public view returns (uint) {
if (_itemName == "medkit") return 1000;
if (_itemName == "ammo_box") return 5000;
if (_itemName == "first_aid_kit") return 10000;
}
//Function to get the cost of upgrading a weapon
function getWeaponUpgradeCost(string _weaponName) public view returns (uint) {
if (_weaponName == "pistol") return 500;
if (_weaponName == "shotgun") return 2500;
if (_weaponName == "rifle") return 5000;
}
//Function to get the reward of a quest
function getQuestReward(string _questName) public view returns (uint) {
if (_questName == "survival") return 100;
if (_questName == "zombie_hunt") return 250;
if (_questName == "rescue_mission") return 500;
}
//Function to get the health reward of a quest
function getQuestHealthReward(string _questName) public view returns (uint) {
if (_questName == "survival") return 10;
if (_questName == "zombie_hunt") return 25;
if (_questName == "rescue_mission") return 50;
}
//Function to get the ammo reward of a quest
function getQuestAmmoReward(string _questName) public view returns (uint) {
if (_questName == "survival") return 5;
if (_questName == "zombie_hunt") return 10;
if (_questName == "rescue_mission") return 20;
}
//Function to get the current level of a weapon
function getWeaponLevel(address _owner, string _weaponName) public view returns (uint) {
return players[_owner].upgrades[_weaponName];
}
//Function to login and get a daily reward
function login() public {
require(players[msg.sender].health > 0);
require(players[msg.sender].ammo > 0);
//increment score
players[msg.sender].score += 10;
//increment health
players[msg.sender].health += 5;
//increment ammo
players[msg.sender].ammo += 2;
}
//Function to save the game progress
function saveProgress() public {
//Save the player's data to storage or IPFS
}
//Function to load the game progress
function loadProgress() public view returns (bool) {
//Load the player's data from storage or IPFS
//if the data is successfully loaded return true, else return false
}
//Function to trade with another player
function trade(address _otherPlayer, string _itemName, uint _amount) public {
require(players[msg.sender].inventory[_itemName] >= _amount);
require(players[_otherPlayer].inventory[_itemName] >= _amount);
players[msg.sender].inventory[_itemName] -= _amount;
players[_otherPlayer].inventory[_itemName] += _amount;
}
}Full source code is here.