Getting emulator errors

Question

I've been trying to reverse engineer a GBA emulator (https://gba.44670.org/) that I found online and using an HTML extractor to try to replicate it. I wanted it to work offline, so I downloaded all the scripts to my computer and ran them there. However, after this, the "Select File" button no longer appears, replaced by the "Loading, please wait..." text line. Digging deeper into the code I found it has something to do with WASM. The code is as follows:

P粉550823577 · Answer

To use a script to keep an application local, remember two things:

The script has been written and will search for resources (js, css, pictures) in the current App directory structure
Requests and file reads are blocked by CORS in most browsers unless you disable CORS preflight checks.

That is, copy the same HTML you get in the response (https://gba.44670.org/ ), which will preserve the file structure. This is what I get (index.html):


    
    
    
    
    
    
    
    44VBA




    
    
        
        
        Savegame management:

        
        
        
        
        Screen filter:
        

        
        Mute Sound

        
        Turbo mode

        
            Cheat Codes(backup your savegame before using it):

            

            
        
        
        Cloud Save:

        

        |

    
    
        44VBA
        
        
            Loading, please wait...
        
        
            
            
        
        
        Ver. 20230107 | GitHub
        
            Your files are processed locally and won't be uploaded to any server.

            This software should not be used to play games you have not legally obtained.

            "GBA", "Game Boy Advance" are trademarks of Nintendo Co.,Ltd, This site is not associated with Nintendo in
            any way.
        
        
            Due to iOS limitations, please open this site(https://gba.44670.org) in Safari, and add it to your
            Home Screen by Share Menu to continue.
            ⬇⬇⬇
        
    
    
        Gamepad disconnected.
    
    
        Menu
        F.F.
        L
        R
        A
        B
        Select
        Start
        ←
        →
        ↑
        ↓

Then you can see the script path where you will create the file:

Additionally, you will need to download the WASM file (651KB compressed, 7.7MB uncompressed). You can download the tarball here (you can find it in the "Network" tab of the dev tools): https://gba.44670.org/build/44gba.wasm

Finally, download all necessary files (you can also download icons and images if you want, but they are not required):

You will get a structure like this:

Now, it would be great if you could deactivate CORS from your browser. But if not, you have to serve it from a local HTTP server. One option is to install the NPM package: https://www.npmjs.com/package/http-server, run npm install --global http-server. After that, just navigate to the project directory in the terminal and start the server:

npx http-server ./ --port 4000

You will see the correct screen and load the ROM, then you are done.

Edit: Solving local CORS issues with a simple Hack

Since I know you are now using ChromeOS and technically don't know how to use Node, NPM and HTTP-Server to handle it, I made some modifications for you and put the WASM binary content directly Enter build/44gba.js and return the binary content on the function readBinary to bypass the CORS issue. You can launch index.html directly. Here is the link to the new build/44gba.js file, just replace its contents with the following file: https://sendeyo.com/en/b02f94b524 You're all good . The following are the changes:

const wasmData = `0061 736d 0100 0000 01c9 011e 6001 7f00
6002 7f7f 0060 0000 6001 7f01 7f60 037f
...  ...  ...  ...  ...  ...  ...  ...
0a00 41c0 8106 0b04 7064 6202`;

// other codes ...

readBinary = filename=>{
    var ret = new Uint8Array(wasmData);
    return ret;
    /* var ret = read_(filename, true);
    if (!ret.buffer) {
        ret = new Uint8Array(ret)
    }
    return ret
    */
}

// other codes ...