Quickstart

Installation

Compile from source

1. Close your existing C++ Unreal Engine project.

2. Create a directory in your app root called Plugins.

3. Clone with

git clone https://github.com/G7DAO/web3.unreal.git ./Plugins/web3Unreal

or if your project uses git, add as a submodule with

git submodule add https://github.com/G7DAO/web3.unreal.git ./Plugins/web3Unreal

1. Generate Visual Studio project files

2. Build through your editor

Pre-compiled from UE Marketplace

Coming Soon!

Making your first call

Get Balance

First, let’s get our rpc endpoint url so we can perform this call on the client or the server.

Go to https://app.infura.io and create an account.

Once you have your chain specific Https url with api key, copy the following blueprint or c++ example to your project.

Before calling this function:

1. Replace https://goerli.infura.io/v3/<API_KEY> with your rpc url. This will be the Url input pin on the Rpc Call Blueprint node.

2. Replace 0x638105AA1B69406560f6428aEFACe3DB9da83c64 with the public address whose balance you want to read

C++Blueprint

#include "HyperPlayUtils.h"
#include "Endpoints/RpcCall.h"

void OnRpcResponse(FString Response, int32 StatusCode)
{
    const bool bWasSuccessful = HyperPlayUtils::StatusCodeIsSuccess(StatusCode);

    UE_LOG(LogTemp, Display, TEXT("Rpc Get Balance Success: %s"), bWasSuccessful ? "true" : "false");
    UE_LOG(LogTemp, Display, TEXT("Rpc Get Balance Response: %s"), *Response);
}

int main(){
const FString request("{ \"method\": \"eth_getBalance\", \"params\": [\"0x638105AA1B69406560f6428aEFACe3DB9da83c64\", \"latest\"], \"id\": 1, \"jsonrpc\": \"2.0\" }");

    URpcCall* RpcCallInstance = URpcCall::RpcCall(nullptr,
        request,
        5,
        "",
        "https://mainnet.infura.io/v3/<API_KEY>");
    RpcCallInstance->GetOnCompletedDelegate().AddRaw(this, &OnRpcResponse);
    RpcCallInstance->Activate();
}

The balance returned will be in hexadecimal. Once converted to decimal, the unit will be in wei.

For example, hexadecimal 0xdad879a6b28f707 to base10 is 985592990756566791

Base10 985592990756566791 wei to ETH is 0.985592990756566791 ETH

Send Token

Now let’s request an ERC20 transfer client side from the HyperPlay connected wallet.

Before calling this function:

1. Replace 0xBA62BCfcAaFc6622853cca2BE6Ac7d845BC0f2Dc with the contract address of the ERC20 token you wish to transfer

2. Replace 0x62bb848ec84D08d55Ea70a19118300bae6658F18 with the public address you would like the HyperPlay connected wallet to send tokens too

3. Replace 100000000000000000000 with the amount of tokens to send in the token contract’s units (18 decimals for most tokens so 10e18 = 1 token)

4. Replace the chain id integer (5 in the following examples) with the chain id that you would like to send the ERC20 tokens on

C++Blueprint

#include "HyperPlayUtils.h"
#include "Endpoints/SendContract.h"

void OnResponse(FString Response, int32 StatusCode)
{
    const bool bWasSuccessful = HyperPlayUtils::StatusCodeIsSuccess(StatusCode);

    UE_LOG(LogTemp, Display, TEXT("SendContract Success: %s"), bWasSuccessful ? "true" : "false");
    UE_LOG(LogTemp, Display, TEXT("SendContract Response: %s"), *Response);
}

int main(){
    const FString address("0x62bb848ec84D08d55Ea70a19118300bae6658F18");
    const FString amount("100000000000000000000");
    TArray<FString> params;
    params.Add(address);
    params.Add(amount);
    USendContract* SendContractInstance = USendContract::SendContract(nullptr,
        "0xBA62BCfcAaFc6622853cca2BE6Ac7d845BC0f2Dc",
        "transfer",
        "",
        params,
        -1,
        "",
        5);
    SendContractInstance->GetOnCompletedDelegate().AddRaw(this, &OnResponse);
    SendContractInstance->Activate();
}

In HyperPlay if the user has created a MetaMask Extension Account, it will appear like so:

The user will need to set the gas price manually through MetaMask in this case.

Note that you will need Goerli ETH and $FAU tokens to complete the example transaction. You can mint the $FAU tokens at https://erc20faucet.com/. A google search for “goerli eth faucet” should send you to several viable goerli eth faucet options.

After the user confirms this transaction in HyperPlay, this will return a transaction hash similar to 0x1b8368d5b67a914a49c76984776849ee3c56a4ac28c92d98103ef18e7215ae2b

Finishing Up

Call the Get Balance function again server side and you should see the new updated on-chain token balance.

Congratulations! You just performed blockchain reads and writes client and server side in Unreal Engine with NO custodial wallets and NO external servers!

Next Steps

Check out our deep dive API docs or go straight to the examples