Add xr compatible instance ext

Author: helcl42

gfx/include/gfx/gfx.h

@@ -992,6 +992,7 @@ typedef struct GfxChainHeader {
 // Instance extensions
 #define GFX_INSTANCE_EXTENSION_SURFACE "gfx_surface"
 #define GFX_INSTANCE_EXTENSION_DEBUG "gfx_debug"
+#define GFX_INSTANCE_EXTENSION_XR_COMPATIBLE "gfx_xr_compatible"
 
 // Device extensions
 #define GFX_DEVICE_EXTENSION_SWAPCHAIN "gfx_swapchain"

gfx/src/backend/webgpu/core/CoreTypes.h

@@ -23,6 +23,7 @@ class TextureView;
 namespace extensions {
     constexpr const char* SURFACE = "gfx_surface";
     constexpr const char* DEBUG = "gfx_debug";
+    constexpr const char* XR_COMPATIBLE = "gfx_xr_compatible";
     constexpr const char* SWAPCHAIN = "gfx_swapchain";
     constexpr const char* TIMELINE_SEMAPHORE = "gfx_timeline_semaphore";
     constexpr const char* ANISOTROPIC_FILTERING = "gfx_anisotropic_filtering";

gfx/src/backend/webgpu/core/system/Instance.cpp

@@ -10,7 +10,7 @@
 namespace gfx::backend::webgpu::core {
 
 namespace {
-    std::vector<WGPUAdapter> discoverAdapters(WGPUInstance instance)
+    std::vector<WGPUAdapter> discoverAdapters(WGPUInstance instance, bool xrCompatible)
     {
         std::vector<WGPUAdapter> adapters;
 
@@ -27,6 +27,15 @@ namespace {
                 WGPURequestAdapterOptions options = WGPU_REQUEST_ADAPTER_OPTIONS_INIT;
                 options.powerPreference = preference;
                 options.forceFallbackAdapter = forceFallback;
+#if defined(__EMSCRIPTEN__)
+                WGPURequestAdapterWebXROptions xrOptions = WGPU_REQUEST_ADAPTER_WEBXR_OPTIONS_INIT;
+                if (xrCompatible) {
+                    xrOptions.xrCompatible = WGPU_TRUE;
+                    options.nextInChain = &xrOptions.chain;
+                }
+#else
+                (void)xrCompatible; // Not applicable for native Dawn
+#endif
 
                 WGPUAdapter adapter = nullptr;
                 bool completed = false;
@@ -71,8 +80,6 @@ namespace {
 
 Instance::Instance(const InstanceCreateInfo& createInfo)
 {
-    (void)createInfo; // Descriptor not used in current implementation
-
     // Request TimedWaitAny feature for proper async callback handling
     // For native Dawn, also request ShaderSourceSPIRV for SPIR-V shader support
     static const WGPUInstanceFeatureName requiredFeatures[] = {
@@ -106,7 +113,10 @@ Instance::Instance(const InstanceCreateInfo& createInfo)
         throw std::runtime_error("Failed to create WebGPU instance");
     }
 
-    std::vector<WGPUAdapter> discoveredAdapters = discoverAdapters(m_instance);
+    const bool xrCompatible = std::find(createInfo.enabledExtensions.begin(), createInfo.enabledExtensions.end(),
+                                  std::string(extensions::XR_COMPATIBLE))
+        != createInfo.enabledExtensions.end();
+    std::vector<WGPUAdapter> discoveredAdapters = discoverAdapters(m_instance, xrCompatible);
     m_adapters.reserve(discoveredAdapters.size());
     for (auto adapter : discoveredAdapters) {
         m_adapters.push_back(std::make_unique<Adapter>(adapter, this));