Second layer blockchain
About second layer solutions #
Any transaction that affects the blockchain takes time to complete, and costs gas. Both these things are obstacles to making blockchain gaming popular, because players usually don’t have the patience to wait that long for their actions to take effect, and aren’t willing to spend money on many transactions as they play.
A common workaround is to keep most of the game-play off-chain, and only carry out blockchain transactions for key events, like earning a game item or registering a high score.
However, another way to overcome these limitations, as well as other scalability issues that are inherent to blockchains, is to rely on a second layer blockchain, also called a side-chain.
A second layer is another blockchain that sits as an intermediary between a decentralized app and the main chain. This layer is more lightweight and can therefore provide faster responses and at a much lower gas cost.
Instead of making transactions directly into the main chain, transactions are done on the side chain, and then it’s the duty of the side-chain to eventually sync these changes with the main chain.
The side-chain is able to provide faster responses because it’s a smaller network with less nodes. The transactions that are carried out in the second layer are initially less secure, but they are eventually committed to the main chain in bulks, and all of the security checks of the main chain can be enforced there.
The side-chain is also able to lower individual transaction costs significantly because it groups many transactions into a single one when syncing with the main chain. So the gas that would need to be paid for one transaction on the main chain can be divided over several thousand transactions.
Also, when syncing with the main chain, several redundant transactions can be avoided entirely, further reducing transaction costs. For example, if Alice transfers 1 ETH to Bob, and then Bob transfers 1 ETH to Carol, then those two transactions can be simplified into one, by registering that Alice transfers directly to Carol.
Decentraland has a partnership with Polygon, who provide their own side-chain on Ethereum. Their side-chain can be used by scenes to support fast and very cheap transactions.
Add Polygon support to a scene #
To easily make use of MANA on Polygon’s side-chain in your scene, use the l2-utils library. This library includes simple functions to allow players in your scene to make transactions with MANA on Polygon’s network, check the player’s current balance of MANA on Polygon, and transfer MANA between mainchain and Polygon.
Players don’t need to switch networks on their browser wallets to operate on Polygon’s network, since these are handled via metatransactions.
Try the Polygon Testnet #
In order to use Polygon’s Matic Testnet, you should first have:
Ether in Ropsten network. You can obtain it for free from various external faucets like this one.
MANA in Ropsten network. You can obtain it for free here MANA faucet.
Then you must configure your Metamask account to include the Matic Testnet.
To do this:
- Switch networks on Metamask by clicking on the name of the current network and selecting Custom RPC at the bottom of the dropdown.
- Fill in ‘Matic Testnet’ as Network name and https://rpc-mumbai.matic.today as New RPC URL and the same value as Block Explorer URL. For Symbol set MATIC
- Click ‘Save’ to add this new network to Metamask.
Note: Learn more about how to set up Matic on their Documentation page