LibGodot For Web or Blazor?

[GeorgeS2019]

godotengine/godot#70796 (comment)

@zorbathut

For what it's worth, I gave a shot turning LibGodot into a .NET web export, but I only had time to put a day or two into it. I got it to the point of loading Godot and trying to load the project at which point it died due to some weird conflict with the virtual filesystem, at which point I realized I needed to get back to my main project and scrapped it. I think it's a viable solution, and arguably better than the Mono solution, it's just not a priority for me right now.

I've got some notes at the bottom of this page and my half-baked-at-best sourcecode here; I am happy to talk to people about this but I don't really have time to devote to coding it.

@thygrrr

thank you for active participation, create a issue here so we have a chance to follow your challenges, feedback etc.

Hopefully we can attract others who could figure out how to make LibGodot works in e.g. winform, etc. as user control. A big unmet need in .NET ecosystem considering the fact that they are many many thousands of winform developers out there.

Getting it to work in Blazor would also mean using Winforms user control to host Blazor or .NET Web.

[thygrrr]

Definitely work in progress :D
Haven't really started, currently busy sorting out some problems that arose with the editor mode (that used to work, but I broke something, now [Tool] classes work, but you can't get a full editor, it seems)

[GeorgeS2019]

Disclaimer: AI Output but provide a possible framework what challenges to watch for.

It also helps to feedback if the current approach will face challenges in the future. Here it lists single threading.

Question?

Which version of Blazor support multi threading and what else needed to make embedding Godot in Blazor with acceptable performance.

.NET Version Multithreading Support Notes
.NET 6 ❌ No real multithreading Browser WASM threads not supported by .NET runtime
.NET 7 ⚠️ Experimental only Not stable, not supported for production
.NET 8 ✅ Yes — official support Requires AOT + true + browser support
.NET 9 Improved support Same requirements as .NET 8, more stable

Important limitation
Even in .NET 8, Blazor’s rendering pipeline is still single‑threaded.
You can run background work on threads, but UI updates must return to the main thread.

.NET 10 improvement in Blazor Multi-Threading

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Remaining Requirements (Still True in .NET 10)

Even with .NET 10, browsers still require:

• SharedArrayBuffer
• COOP/COEP headers
• HTTPS
• AOT compilation
• <WasmEnableThreads>true</WasmEnableThreads>

These are browser constraints, not .NET constraints.

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Integrating libgodot.dll with Blazor is a unique challenge because it bridges two fundamentally different execution environments: the WebAssembly (WASM) sandbox of the browser and the Native/C++ architecture of Godot.

Because Blazor WebAssembly cannot load a standard Windows .dll (which is compiled for x86/x64 instruction sets), you have to change your compilation target and communication strategy.

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1. The Architecture Shift: From DLL to WASM

A .dll is a Windows-specific binary. For Blazor, you must compile Godot as a WebAssembly Side Module (.wasm).

• The Bridge: You will use Emscripten to compile the LibGodot source code.

• The Hosting: Blazor will act as the host, providing an HTML <canvas> element that LibGodot will "claim" to render its frames.

High-Level Integration Flow

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2. Technical Implementation Steps

A. Compiling LibGodot for Web

You cannot use the 2dog Windows build directly. You must build Godot from source using the platform=web target, ensuring the libgodot patches (which allow Godot to run as a library rather than an app) are applied.

1. Set up the Emscripten SDK (emsdk).

2. Compile Godot with symbols enabled for library export:

   scons platform=web target=template_debug libgodot=yes

B. JavaScript Interop (The "Glue")

Blazor cannot talk to a C++ WASM module directly in a "native" way. You need a JavaScript middleman.

1. Define the Canvas: In your Blazor component (.razor), create the target:

   HTML

   <canvas id="godot-canvas" oncontextmenu="event.preventDefault()"></canvas>
   

2. JSInterop Call: Use IJSRuntime in Blazor to call a loader script that initializes the Godot WASM module and points it to #godot-canvas.

C. Memory Sharing with Blazor

To pass data between Blazor C# and LibGodot, you should use the Emscripten Shared Memory feature.

• Blazor (C#): Uses System.Runtime.InteropServices.JavaScript to pass references.

• LibGodot (C++): Uses emscripten_bindings to expose functions.

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3. Communication Strategies

Method | Best For | Complexity -- | -- | -- P/Invoke (Mono WASM) | Direct calls from Blazor C# to Godot C++ functions. | High Shared Array Buffer | High-speed data transfer (e.g., passing physics data or textures). | Medium JSInvokable | Sending Godot signals (like "Button Clicked") back to Blazor UI. | Low

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4. Key Limitations to Watch For

• Single Threading: By default, browsers are single-threaded. If Godot performs a heavy calculation, it will "freeze" the Blazor UI unless you enable SharedArrayBuffer and Web Workers in your server headers (COOP/COEP).

• Graphics API: LibGodot in Blazor will be limited to WebGL 2.0 (Compatibility mode in Godot 4). You cannot use the Forward+ (Vulkan) renderer in the browser yet.

[neiesc]

@thygrrr Hi,

I'm running on my local machine:

Do you have PR ou branch, need help?

[ComplexRobot]

@neiesc how did you do that? I'm assuming this isn't useful to the average user?

[MihaMarkic]

@thygrrr Hi,

I'm running on my local machine:

Is it available online?