Refactor: factorize WGPU init code for 3D tests

Extracted duplicate WGPU initialization boilerplate from test_3d_physics,
test_3d_render, and test_mesh into shared helper (test_3d_helpers).

**Changes:**
- New: src/tests/common/test_3d_helpers.{h,cc} (~120 LOC)
- Removed ~280 LOC of duplicate init_wgpu() implementations
- Net savings: -141 LOC

**Benefits:**
- Single source of truth for surface+device initialization
- Eliminates cross-compile #ifdef duplication
- Easier maintenance for callback API changes

All 34 tests pass.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

1 files changed, 6 insertions, 94 deletions

diff --git a/src/tests/3d/test_3d_render.cc b/src/tests/3d/test_3d_render.cc
index eee46ba..49a265f 100644
--- a/src/tests/3d/test_3d_render.cc
+++ b/src/tests/3d/test_3d_render.cc
@@ -10,6 +10,7 @@
 #include "gpu/texture_manager.h"
 #include "platform/platform.h"
 #include "procedural/generator.h"
+#include "../common/test_3d_helpers.h"
 #include <cmath>
 #include <cstdio>
 #include <cstring>
@@ -23,100 +24,8 @@ static Camera g_camera;
 static WGPUDevice g_device = nullptr;
 static WGPUQueue g_queue = nullptr;
 static WGPUSurface g_surface = nullptr;
-static WGPUAdapter g_adapter = nullptr;
 static WGPUTextureFormat g_format = WGPUTextureFormat_Undefined;
 
-// ... (init_wgpu implementation same as before)
-void init_wgpu(PlatformState* platform_state) {
-  WGPUInstance instance = wgpuCreateInstance(nullptr);
-  if (!instance) {
-    fprintf(stderr, "Failed to create WGPU instance.\n");
-    exit(1);
-  }
-
-  g_surface = platform_create_wgpu_surface(instance, platform_state);
-  if (!g_surface) {
-    fprintf(stderr, "Failed to create WGPU surface.\n");
-    exit(1);
-  }
-
-  WGPURequestAdapterOptions adapter_opts = {};
-  adapter_opts.compatibleSurface = g_surface;
-  adapter_opts.powerPreference = WGPUPowerPreference_HighPerformance;
-
-#if defined(DEMO_CROSS_COMPILE_WIN32)
-  auto on_adapter = [](WGPURequestAdapterStatus status, WGPUAdapter adapter,
-                       const char* message, void* userdata) {
-    if (status == WGPURequestAdapterStatus_Success) {
-      *(WGPUAdapter*)userdata = adapter;
-    }
-  };
-  wgpuInstanceRequestAdapter(instance, &adapter_opts, on_adapter, &g_adapter);
-#else
-  auto on_adapter = [](WGPURequestAdapterStatus status, WGPUAdapter adapter,
-                       WGPUStringView message, void* userdata, void* user2) {
-    (void)user2;
-    if (status == WGPURequestAdapterStatus_Success) {
-      *(WGPUAdapter*)userdata = adapter;
-    }
-  };
-  WGPURequestAdapterCallbackInfo adapter_cb = {};
-  adapter_cb.mode = WGPUCallbackMode_WaitAnyOnly;
-  adapter_cb.callback = on_adapter;
-  adapter_cb.userdata1 = &g_adapter;
-  wgpuInstanceRequestAdapter(instance, &adapter_opts, adapter_cb);
-#endif
-
-  while (!g_adapter) {
-    platform_wgpu_wait_any(instance);
-  }
-
-  WGPUDeviceDescriptor device_desc = {};
-
-#if defined(DEMO_CROSS_COMPILE_WIN32)
-  auto on_device = [](WGPURequestDeviceStatus status, WGPUDevice device,
-                      const char* message, void* userdata) {
-    if (status == WGPURequestDeviceStatus_Success) {
-      *(WGPUDevice*)userdata = device;
-    }
-  };
-  wgpuAdapterRequestDevice(g_adapter, &device_desc, on_device, &g_device);
-#else
-  auto on_device = [](WGPURequestDeviceStatus status, WGPUDevice device,
-                      WGPUStringView message, void* userdata, void* user2) {
-    (void)user2;
-    if (status == WGPURequestDeviceStatus_Success) {
-      *(WGPUDevice*)userdata = device;
-    }
-  };
-  WGPURequestDeviceCallbackInfo device_cb = {};
-  device_cb.mode = WGPUCallbackMode_WaitAnyOnly;
-  device_cb.callback = on_device;
-  device_cb.userdata1 = &g_device;
-  wgpuAdapterRequestDevice(g_adapter, &device_desc, device_cb);
-#endif
-
-  while (!g_device) {
-    platform_wgpu_wait_any(instance);
-  }
-
-  g_queue = wgpuDeviceGetQueue(g_device);
-
-  WGPUSurfaceCapabilities caps = {};
-  wgpuSurfaceGetCapabilities(g_surface, g_adapter, &caps);
-  g_format = caps.formats[0];
-
-  WGPUSurfaceConfiguration config = {};
-  config.device = g_device;
-  config.format = g_format;
-  config.usage = WGPUTextureUsage_RenderAttachment;
-  config.width = platform_state->width;
-  config.height = platform_state->height;
-  config.presentMode = WGPUPresentMode_Fifo;
-  config.alphaMode = WGPUCompositeAlphaMode_Opaque;
-  wgpuSurfaceConfigure(g_surface, &config);
-}
-
 void setup_scene() {
   g_scene.clear();
   srand(12345); // Fixed seed
@@ -211,8 +120,11 @@ int main(int argc, char** argv) {
 
   PlatformState platform_state = platform_init(false, 1280, 720);
 
-  // The test's own WGPU init sequence
-  init_wgpu(&platform_state);
+  WgpuSurfaceContext wgpu_ctx = init_wgpu_with_surface(&platform_state);
+  g_device = wgpu_ctx.device;
+  g_queue = wgpu_ctx.queue;
+  g_surface = wgpu_ctx.surface;
+  g_format = wgpu_ctx.format;
 
   InitShaderComposer();