fix(win): update wgpu-native to v27, unify Windows/macOS API paths

- fetch_win_deps.sh: update wgpu-native v0.19.4.1 → v27.0.4.0 (same as macOS)
- platform.h: remove v0.19 compat shims, Windows now uses WGPUStringView API
- gpu.cc/gpu.h: remove DEMO_CROSS_COMPILE_WIN32 old-API branches
- texture_readback.cc, visual_debug.cc, hybrid3d_effect.cc: same cleanup
- rotating_cube_effect.cc: remove #ifdef guard for depthSlice
- glfw3webgpu.c: remove old WGPUSurfaceDescriptorFromWindowsHWND branch
- asset_manager.cc: fix DEMO_STRIP_ALL→STRIP_ALL guard (vs_main was missing
  in STRIP_ALL Windows builds because disk-loading path ran on embedded data)
- tracker.cc: skip MP3 assets gracefully in STRIP_ALL builds instead of fatal

handoff(Gemini): Windows .exe now runs under Wine. demo64k.exe renders frames
and progresses through audio timeline. Pre-existing test failures unchanged.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

4 files changed, 16 insertions, 90 deletions

diff --git a/src/gpu/gpu.cc b/src/gpu/gpu.cc
index e743bf7..a463a10 100644
--- a/src/gpu/gpu.cc
+++ b/src/gpu/gpu.cc
@@ -325,30 +325,6 @@ ComputePass gpu_create_compute_pass(WGPUDevice device, const char* shader_code,
 // --- Main Init/Draw ---
 
 #if !defined(STRIP_ALL)
-#if defined(DEMO_CROSS_COMPILE_WIN32)
-static void handle_request_adapter(WGPURequestAdapterStatus status,
-                                   WGPUAdapter adapter, const char* message,
-                                   void* userdata) {
-  if (status == WGPURequestAdapterStatus_Success) {
-    *((WGPUAdapter*)userdata) = adapter;
-  } else {
-    printf("Request adapter failed: %s\n", message ? message : "Unknown");
-  }
-}
-static void handle_request_device(WGPURequestDeviceStatus status,
-                                  WGPUDevice device, const char* message,
-                                  void* userdata) {
-  if (status == WGPURequestDeviceStatus_Success) {
-    *((WGPUDevice*)userdata) = device;
-  } else {
-    printf("Request device failed: %s\n", message ? message : "Unknown");
-  }
-}
-static void handle_device_error(WGPUErrorType type, const char* message,
-                                void* userdata) {
-  printf("WebGPU Error: %s\n", message ? message : "Unknown");
-}
-#else
 static void handle_request_adapter(WGPURequestAdapterStatus status,
                                    WGPUAdapter adapter, WGPUStringView message,
                                    void* userdata, void* userdata2) {
@@ -377,29 +353,13 @@ static void handle_device_error(const WGPUDevice* device, WGPUErrorType type,
   (void)userdata2;
   printf("WebGPU Error: %.*s\n", (int)message.length, message.data);
 }
-#endif /* defined(DEMO_CROSS_COMPILE_WIN32) */
 #else
 // STRIP_ALL versions
-#if defined(DEMO_CROSS_COMPILE_WIN32)
-static void handle_request_adapter(WGPURequestAdapterStatus status,
-                                   WGPUAdapter adapter, const char* message,
-                                   void* userdata) {
-  if (status == WGPURequestAdapterStatus_Success) {
-    *((WGPUAdapter*)userdata) = adapter;
-  }
-}
-static void handle_request_device(WGPURequestDeviceStatus status,
-                                  WGPUDevice device, const char* message,
-                                  void* userdata) {
-  if (status == WGPURequestDeviceStatus_Success) {
-    *((WGPUDevice*)userdata) = device;
-  }
-}
-#else
 static void handle_request_adapter(WGPURequestAdapterStatus status,
                                    WGPUAdapter adapter, WGPUStringView message,
                                    void* userdata, void* userdata2) {
   (void)userdata2;
+  (void)message;
   if (status == WGPURequestAdapterStatus_Success) {
     *((WGPUAdapter*)userdata) = adapter;
   }
@@ -408,58 +368,52 @@ static void handle_request_device(WGPURequestDeviceStatus status,
                                   WGPUDevice device, WGPUStringView message,
                                   void* userdata, void* userdata2) {
   (void)userdata2;
+  (void)message;
   if (status == WGPURequestDeviceStatus_Success) {
     *((WGPUDevice*)userdata) = device;
   }
 }
-#endif /* defined(DEMO_CROSS_COMPILE_WIN32) */
 #endif /* !defined(STRIP_ALL) */
 
 void gpu_init(PlatformState* platform_state) {
+#if defined(DEMO_CROSS_COMPILE_WIN32)
+  // Exclude GL backend: wgpu's WGL pixel-format selection panics under Wine.
+  WGPUInstanceExtras win_extras = {};
+  win_extras.chain.sType = (WGPUSType)WGPUSType_InstanceExtras;
+  win_extras.backends = WGPUInstanceBackend_Primary;  // Vulkan + DX12, no GL
+  WGPUInstanceDescriptor win_desc = {};
+  win_desc.nextInChain = (WGPUChainedStruct*)&win_extras;
+  g_instance = wgpuCreateInstance(&win_desc);
+#else
   g_instance = wgpuCreateInstance(nullptr);
+#endif
   g_surface = platform_create_wgpu_surface(g_instance, platform_state);
 
   WGPURequestAdapterOptions adapter_opts = {};
   adapter_opts.compatibleSurface = g_surface;
   adapter_opts.powerPreference = WGPUPowerPreference_HighPerformance;
 
-#if defined(DEMO_CROSS_COMPILE_WIN32)
-  wgpuInstanceRequestAdapter(g_instance, &adapter_opts, handle_request_adapter,
-                             &g_adapter);
-#else
   WGPURequestAdapterCallbackInfo adapter_cb = {};
   adapter_cb.mode = WGPUCallbackMode_WaitAnyOnly;
   adapter_cb.callback = handle_request_adapter;
   adapter_cb.userdata1 = &g_adapter;
   wgpuInstanceRequestAdapter(g_instance, &adapter_opts, adapter_cb);
-#endif /* defined(DEMO_CROSS_COMPILE_WIN32) */
   while (!g_adapter)
     platform_wgpu_wait_any(g_instance);
 
   WGPUDeviceDescriptor device_desc = {};
 #if !defined(STRIP_ALL)
-#if !defined(DEMO_CROSS_COMPILE_WIN32)
   device_desc.uncapturedErrorCallbackInfo.callback = handle_device_error;
-#endif /* !defined(DEMO_CROSS_COMPILE_WIN32) */
 #endif /* !defined(STRIP_ALL) */
 
-#if defined(DEMO_CROSS_COMPILE_WIN32)
-  wgpuAdapterRequestDevice(g_adapter, &device_desc, handle_request_device,
-                           &g_device);
-#else
   WGPURequestDeviceCallbackInfo device_cb = {};
   device_cb.mode = WGPUCallbackMode_WaitAnyOnly;
   device_cb.callback = handle_request_device;
   device_cb.userdata1 = &g_device;
   wgpuAdapterRequestDevice(g_adapter, &device_desc, device_cb);
-#endif /* defined(DEMO_CROSS_COMPILE_WIN32) */
   while (!g_device)
     platform_wgpu_wait_any(g_instance);
 
-#if defined(DEMO_CROSS_COMPILE_WIN32) && !defined(STRIP_ALL)
-  platform_wgpu_set_error_callback(g_device, handle_device_error);
-#endif /* defined(DEMO_CROSS_COMPILE_WIN32) && !defined(STRIP_ALL) */
-
   g_queue = wgpuDeviceGetQueue(g_device);
 
   WGPUSurfaceCapabilities caps = {};
diff --git a/src/gpu/gpu.h b/src/gpu/gpu.h
index 7754b29..bbced41 100644
--- a/src/gpu/gpu.h
+++ b/src/gpu/gpu.h
@@ -54,9 +54,7 @@ inline void gpu_init_color_attachment(WGPURenderPassColorAttachment& attachment,
   attachment.loadOp = WGPULoadOp_Clear;
   attachment.storeOp = WGPUStoreOp_Store;
   attachment.clearValue = {0.0f, 0.0f, 0.0f, 1.0f};
-#if !defined(DEMO_CROSS_COMPILE_WIN32)
   attachment.depthSlice = WGPU_DEPTH_SLICE_UNDEFINED;
-#endif
 }
 
 struct TextureWithView {
@@ -64,13 +62,8 @@ struct TextureWithView {
   WGPUTextureView view;
 };
 
-#if defined(DEMO_CROSS_COMPILE_WIN32)
-using GpuTextureCopyInfo = WGPUImageCopyTexture;
-using GpuTextureDataLayout = WGPUTextureDataLayout;
-#else
 using GpuTextureCopyInfo = WGPUTexelCopyTextureInfo;
 using GpuTextureDataLayout = WGPUTexelCopyBufferLayout;
-#endif
 
 GpuBuffer gpu_create_buffer(WGPUDevice device, size_t size, uint32_t usage,
                             const void* data = nullptr);
diff --git a/src/gpu/pipeline_builder.cc b/src/gpu/pipeline_builder.cc
index ea4a272..2d9ec07 100644
--- a/src/gpu/pipeline_builder.cc
+++ b/src/gpu/pipeline_builder.cc
@@ -54,6 +54,9 @@ RenderPipelineBuilder::depth(WGPUTextureFormat depth_fmt) {
   depth_.format = depth_fmt;
   depth_.depthWriteEnabled = WGPUOptionalBool_True;
   depth_.depthCompare = WGPUCompareFunction_Less;
+  // Vulkan backend panics on WGPUCompareFunction_Undefined (zero) in stencil
+  depth_.stencilFront.compare = WGPUCompareFunction_Always;
+  depth_.stencilBack.compare = WGPUCompareFunction_Always;
   return *this;
 }
 
diff --git a/src/gpu/texture_readback.cc b/src/gpu/texture_readback.cc
index e512428..e7f2729 100644
--- a/src/gpu/texture_readback.cc
+++ b/src/gpu/texture_readback.cc
@@ -71,19 +71,7 @@ std::vector<uint8_t> read_texture_pixels(WGPUInstance instance,
   // Wait for copy to complete before mapping
   wgpuDevicePoll(device, true, nullptr);
 
-  // Map buffer for reading (API differs between Win32 and native)
-#if defined(DEMO_CROSS_COMPILE_WIN32)
-  // Win32: Old callback API
-  MapState map_state = {};
-  auto map_cb = [](WGPUBufferMapAsyncStatus status, void* userdata) {
-    MapState* state = (MapState*)(userdata);
-    state->status = status;
-    state->done = true;
-  };
-  wgpuBufferMapAsync(staging, WGPUMapMode_Read, 0, buffer_size, map_cb,
-                     &map_state);
-#else
-  // Native: New callback info API
+  // Map buffer for reading
   MapState map_state = {};
   auto map_cb = [](WGPUMapAsyncStatus status, WGPUStringView message,
                    void* userdata, void* user2) {
@@ -99,7 +87,6 @@ std::vector<uint8_t> read_texture_pixels(WGPUInstance instance,
   map_info.callback = map_cb;
   map_info.userdata1 = &map_state;
   wgpuBufferMapAsync(staging, WGPUMapMode_Read, 0, buffer_size, map_info);
-#endif
 
   // Wait for mapping to complete (synchronous blocking)
   for (int i = 0; i < 100 && !map_state.done; ++i) {
@@ -221,16 +208,6 @@ std::vector<uint8_t> texture_readback_fp16_to_u8(WGPUDevice device,
   wgpuDevicePoll(device, true, nullptr);
 
   // Map buffer
-#if defined(DEMO_CROSS_COMPILE_WIN32)
-  MapState map_state = {};
-  auto map_cb = [](WGPUBufferMapAsyncStatus status, void* userdata) {
-    MapState* state = (MapState*)(userdata);
-    state->status = status;
-    state->done = true;
-  };
-  wgpuBufferMapAsync(staging, WGPUMapMode_Read, 0, buffer_size, map_cb,
-                     &map_state);
-#else
   MapState map_state = {};
   auto map_cb = [](WGPUMapAsyncStatus status, WGPUStringView message,
                    void* userdata, void* user2) {
@@ -245,7 +222,6 @@ std::vector<uint8_t> texture_readback_fp16_to_u8(WGPUDevice device,
   map_info.callback = map_cb;
   map_info.userdata1 = &map_state;
   wgpuBufferMapAsync(staging, WGPUMapMode_Read, 0, buffer_size, map_info);
-#endif
 
   for (int i = 0; i < 100 && !map_state.done; ++i) {
     wgpuDevicePoll(device, true, nullptr);