Vulkan Rendering Backend

Uno Platform supports Vulkan as an optional hardware-accelerated rendering backend for the Skia renderer on Android, Linux (X11), and Windows (Win32).

Vulkan provides lower driver overhead and more efficient GPU utilization compared to OpenGL on supported hardware. When enabled, the Skia drawing operations are backed by a Vulkan graphics pipeline instead of OpenGL.

Note

Vulkan rendering is opt-in. The default rendering backend remains OpenGL (or software) on all platforms. Enabling Vulkan when it is not available on the target device will automatically fall back to the default backend.

Platform Support

Platform Vulkan Support Minimum Requirement
Android Yes Android 7.0+ (API 24) with Vulkan-capable GPU
Linux (X11) Yes Vulkan ICD (Mesa or proprietary drivers)
Windows (Win32) Yes Vulkan runtime + compatible GPU driver
macOS No Uses Metal instead
WebAssembly No Uses WebGL instead

Enabling Vulkan

Using the Host Builder (Recommended — Desktop)

On desktop platforms, the preferred way to enable Vulkan is through the platform host builder:

var host = UnoPlatformHostBuilder.Create()
    .App(() => new App())
    .UseX11(b => b.RenderingBackend(X11RenderingBackend.Vulkan))
    .UseWin32(b => b.RenderingBackend(Win32RenderingBackend.Vulkan))
    .UseLinuxFrameBuffer()
    .UseMacOS()
    .Build();

host.Run();

Each platform has its own rendering backend enum reflecting the backends it supports:

X11RenderingBackend (Linux):

Value Description
Default Auto-detect: try OpenGL, fall back to software
Vulkan Vulkan with fallback to OpenGL/software
OpenGL OpenGL via GLX
OpenGLES OpenGL ES via EGL
Software CPU-based software rendering

Win32RenderingBackend (Windows):

Value Description
Default Auto-detect: try OpenGL, fall back to software
Vulkan Vulkan with fallback to OpenGL/software
OpenGL OpenGL via WGL
Software CPU-based software rendering

Using FeatureConfiguration Flags

For backwards compatibility and for platforms without a host builder (such as Android), rendering can be configured via FeatureConfiguration.Rendering:

// Android — set before ApplicationActivity.OnStart()
FeatureConfiguration.Rendering.UseVulkanOnSkiaAndroid = true;

// Linux/X11 — set before host.Build()
FeatureConfiguration.Rendering.UseVulkanOnX11 = true;

// Windows/Win32 — set before host.Build()
FeatureConfiguration.Rendering.UseVulkanOnWin32 = true;
Note

When both the builder API and the feature flags are used, the builder takes precedence if it runs after the flag is set (which is the typical case). If you set a feature flag after Build(), the flag value wins.

Android

Android does not use a host builder. Enable Vulkan in your Application class or app startup, before the activity is created:

FeatureConfiguration.Rendering.UseVulkanOnSkiaAndroid = true;

Fallback Behavior

When Vulkan is requested but unavailable, the application automatically falls back to the next available backend:

  1. Vulkan (if requested)
  2. OpenGL / OpenGL ES (platform default)
  3. Software rendering (CPU-based)

No user intervention is required. A diagnostic log message is emitted indicating which backend was selected and why.

Diagnostic Logging

Enable debug logging to see which rendering backend was selected:

builder.AddFilter("Uno.UI.Runtime.Skia", LogLevel.Information);

When Vulkan is successfully initialized:

Vulkan rendering initialized: <device name>, <driver version>

When Vulkan falls back:

Vulkan rendering not available: <reason>. Falling back to OpenGL ES.

Troubleshooting

Vulkan not available on Linux

Ensure Vulkan drivers are installed:

# Debian/Ubuntu (Mesa)
sudo apt install mesa-vulkan-drivers

# Verify
vulkaninfo

Vulkan not available on Android

  • Vulkan requires Android 7.0 (API 24) or higher
  • Some low-end or older devices may have Vulkan listed but with incomplete driver support — in these cases the fallback to OpenGL ES is automatic

Vulkan not available on Windows

Ensure your GPU driver includes Vulkan support. Most modern NVIDIA, AMD, and Intel drivers include Vulkan. You can verify with the Vulkan SDK vulkaninfo tool.

Application crashes with Vulkan enabled

If you experience crashes with Vulkan enabled, disable it and file an issue:

// Temporarily disable Vulkan
FeatureConfiguration.Rendering.UseVulkanOnSkiaAndroid = false;
FeatureConfiguration.Rendering.UseVulkanOnX11 = false;
FeatureConfiguration.Rendering.UseVulkanOnWin32 = false;