mikeghen / saverville

Farmville-style game built around onchain certificates of deposit

Saverville

Overview

Saverville is a decentralized game based on blockchain technology that simulates farming activities using a financial model akin to certificates of deposit (CDs). Players, known as "Farmers," manage virtual farms, growing crops that represent financial investments with defined maturity periods.

Game Mechanics

• Purchasing Seeds: Farmers buy seeds from the Market.
• Planting Seeds: Farmers plant their seeds on various plots within their farm.
• Growth Period: Seeds mature over time, with a random variance in growth duration.
• Harvesting: Harvested plants represent the maturity of the CDs, yielding the initial investment plus interest.
• Selling Crops: Farmers can sell their harvested crops at the Market.
• Withdrawing Funds: Funds can be withdrawn, similar to withdrawing from a savings account.

Smart Contracts

Flowchart

graph TD
    Farm[Farm] -->|1. buy seeds| Market[Market]
    Farm -->|2. plant seeds| FarmPlot[Farm Plot]
    Farm -->|3. harvests crops| FarmPlot
    Farm -->|4. sells crops| Market

    style Market fill:#f90,stroke:#333,stroke-width:2px
    style Farm fill:#303,stroke:#333,stroke-width:2px
    style FarmPlot fill:#cf8,stroke:#333,stroke-width:2px

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1. Buy Seeds: Farmers purchase seeds from the Market.
2. Plant Seeds: Farmers plant seeds in their farm plots.
3. Harvest Crops: Farmers harvest mature crops from their farm plots.
4. Sell Crops: Farmers sell harvested crops at the Market.

Smart Contract Components

1. Market

Handles all transactions related to buying seeds and selling crops.

Methods

• buySeeds(uint quantity)
  • Farmers purchase seeds, which are added to their farm.
• sellCrops(uint plotId, uint amount)
  • Farmers sell crops from a specific plot for in-game currency.

2. Farm

Manages the individual farmer's entire farming operation, containing multiple farm plots.

Variables

• address owner - Owner of the farm.
• FarmPlot[100] plots - Array of plots within the farm.
• uint256 plantableSeeds - Number of seeds that can be planted.
• uint256 totalEarnings - Total earnings in ETH from harvested plants.
• uint256 totalHarvestedPlants - Total number of harvested plants.

Methods

• plantSeed(uint256 plotId)
  • Plants a seed in a specified plot within the farm.
• waterPlant(uint256 plotId)
  • Waters the planted seed, setting the harvest time.
• harvestPlant(uint256 plotId)
  • Harvests the mature plant from a specified plot.

3. FarmPlot

Tracks the state of each plot and its maturity.

Variables

• uint state - State of the plot (0 = free, 1 = seeded, 2 = watered).
• uint harvestAt - Timestamp when the plot can be harvested.

Methods

• plant()
  • Changes the state to seeded.
• water()
  • Changes the state to watered and sets the harvest time.
• harvest()
  • Changes the state to free after harvest.

Inheritance and Interfaces

• VRFConsumerBaseV2: Used to get random values for the growth period from Chainlink VRF.
• VRFCoordinatorV2Interface: Interface for Chainlink VRF Coordinator.

Events

• SeedPurchased
  • address buyer, uint quantity
• SeedPlanted
  • address farmAddress, uint plotId
• PlantWatered
  • address farmAddress, uint plotId, uint harvestAt
• PlantHarvested
  • address farmAddress, uint plotId