add plugin camera desktop

plugins/camera_desktop/windows/camera.h

@@ -0,0 +1,220 @@
+#pragma once
+
+#include <flutter/encodable_value.h>
+#include <flutter/method_channel.h>
+#include <flutter/method_result.h>
+#include <flutter/texture_registrar.h>
+#include <d3d11.h>
+#include <mfapi.h>
+#include <mfcaptureengine.h>
+#include <mfidl.h>
+#include <wrl/client.h>
+
+#include <atomic>
+#include <chrono>
+#include <condition_variable>
+#include <functional>
+#include <memory>
+#include <mutex>
+#include <string>
+#include <thread>
+#include <vector>
+
+#include "camera_texture.h"
+#include "record_handler.h"
+
+using Microsoft::WRL::ComPtr;
+
+enum class CameraState {
+  kCreated,
+  kInitializing,
+  kRunning,
+  kPaused,
+  kDisposing,
+  kDisposed,
+};
+
+struct CameraConfig {
+  std::wstring symbolic_link;
+  int  resolution_preset = 4;  // 0=low … 4=max
+  bool enable_audio      = false;
+  int  target_fps        = 30;
+  int  target_bitrate    = 0;  // <=0 means use dynamic default ladder.
+  int  audio_bitrate     = 0;
+};
+
+class Camera : public std::enable_shared_from_this<Camera> {
+ public:
+  using PlatformTaskPoster =
+      std::function<void(std::function<void()>, const char* tag)>;
+
+  Camera(int camera_id, flutter::TextureRegistrar* texture_registrar,
+         flutter::MethodChannel<flutter::EncodableValue>* channel,
+         CameraConfig config,
+         PlatformTaskPoster platform_task_poster);
+  ~Camera();
+
+  int64_t RegisterTexture();
+
+  void Initialize(
+      std::unique_ptr<flutter::MethodResult<flutter::EncodableValue>> result);
+
+  void TakePicture(
+      std::unique_ptr<flutter::MethodResult<flutter::EncodableValue>> result);
+
+  void StartVideoRecording(
+      std::unique_ptr<flutter::MethodResult<flutter::EncodableValue>> result);
+  void StopVideoRecording(
+      std::unique_ptr<flutter::MethodResult<flutter::EncodableValue>> result);
+
+  void StartImageStream();
+  void StopImageStream();
+
+  // FFI image stream access.
+  void* GetImageStreamBuffer();
+  void  RegisterImageStreamCallback(void (*callback)(int32_t));
+  void  UnregisterImageStreamCallback();
+
+  void PausePreview();
+  void ResumePreview();
+  void DisposeAsync(std::function<void()> on_done);
+  void Dispose();
+  bool IsDisposedOrDisposing() const;
+
+  // Called from COM callbacks, must be public.
+  void OnEngineEvent(IMFMediaEvent* event);
+  void OnPreviewSample(IMFSample* sample);
+
+ private:
+  uint32_t MaxPreviewHeightForPreset() const;
+  uint32_t MaxRecordHeightForPreset() const;
+  int ComputeDefaultBitrate(int width, int height, int fps) const;
+
+  HRESULT CreateCaptureEngine();
+  HRESULT FindBaseMediaTypes();
+  HRESULT StartPreviewInternal();
+
+  void CompleteInit(bool success, const std::string& error,
+                    int width = 0, int height = 0);
+  void FailAllPendingResults(const std::string& error);
+
+  void DisposeInternal();
+  void SendError(const std::string& description);
+  int  InitElapsedMs() const;
+
+  static void FlipHorizontal(uint8_t* data, int width, int height);
+  static void SwapRBChannels(uint8_t* data, int width, int height);
+
+  void PostImageStreamFrame(const uint8_t* data, int width, int height);
+  void ImageStreamLoop();
+
+  // ── Identity ────────────────────────────────────────────────────────────
+  int        camera_id_;
+  int64_t    texture_id_ = -1;
+  CameraConfig config_;
+
+  flutter::TextureRegistrar*                           texture_registrar_;
+  flutter::MethodChannel<flutter::EncodableValue>*     channel_;
+  PlatformTaskPoster                                   platform_task_poster_;
+  std::shared_ptr<CameraTexture>                       texture_;
+  // Guards texture_ against concurrent teardown: preview samples arrive on an
+  // MF callback thread and touch texture_, while DisposeInternal frees it on
+  // the dispose thread. See CRASH.md.
+  std::mutex                                           texture_mutex_;
+
+  // ── Capture engine + D3D11 ─────────────────────────────────────────────
+  ComPtr<IMFCaptureEngine>      capture_engine_;
+  ComPtr<IMFCapturePreviewSink> preview_sink_;
+  ComPtr<ID3D11Device>          dx11_device_;
+  ComPtr<IMFDXGIDeviceManager>  dxgi_device_manager_;
+  UINT                          dx_device_reset_token_ = 0;
+
+  // Negotiated media types (set in FindBaseMediaTypes before preview starts).
+  ComPtr<IMFMediaType> base_preview_media_type_;
+  ComPtr<IMFMediaType> base_capture_media_type_;
+  int preview_width_  = 0;
+  int preview_height_ = 0;
+  int record_width_   = 0;
+  int record_height_  = 0;
+  int record_fps_     = 0;
+
+  // ── Recording ──────────────────────────────────────────────────────────
+  std::unique_ptr<RecordHandler> record_handler_;
+  std::wstring                   current_record_path_;
+  std::atomic<bool>              is_recording_{false};
+  int                            active_record_bitrate_ = 0;
+
+  // ── Preview / frame state ───────────────────────────────────────────────
+  std::atomic<bool> first_frame_received_{false};
+  std::atomic<bool> preview_paused_{false};
+  std::atomic<bool> image_streaming_{false};
+
+  // ── Latest frame for photo capture (natural BGRA) ─────────────────────
+  std::vector<uint8_t> latest_frame_;
+  std::mutex           latest_frame_mutex_;
+
+  // ── Per-frame working buffer ────────────────────────────────────────────
+  std::vector<uint8_t> packed_frame_;
+
+  // ── Camera state ────────────────────────────────────────────────────────
+  CameraState        state_ = CameraState::kCreated;
+  mutable std::mutex state_mutex_;
+
+  // ── Pending async MethodResults ─────────────────────────────────────────
+  mutable std::mutex pending_mutex_;
+  std::unique_ptr<flutter::MethodResult<flutter::EncodableValue>>
+      pending_init_;
+  std::unique_ptr<flutter::MethodResult<flutter::EncodableValue>>
+      pending_start_record_;
+  std::unique_ptr<flutter::MethodResult<flutter::EncodableValue>>
+      pending_stop_record_;
+
+  // ── Init timing (diagnostics) ───────────────────────────────────────────
+  std::chrono::steady_clock::time_point create_start_{};
+
+  // ── Initialisation timeout ──────────────────────────────────────────────
+  std::thread             init_timeout_thread_;
+  std::mutex              init_timeout_cancel_mutex_;
+  std::condition_variable init_timeout_cancel_cv_;
+  bool                    init_timeout_cancelled_ = false;
+
+  // ── Image stream delivery ───────────────────────────────────────────────
+  struct ImageStreamBuffer {
+    int64_t  sequence;
+    int32_t  width;
+    int32_t  height;
+    int32_t  bytes_per_row;
+    int32_t  format;   // 0=BGRA, 1=RGBA
+    int32_t  ready;    // 1=Dart may read, 0=native writing
+    int32_t  _pad;
+    uint8_t  pixels[1];
+  };
+
+  ImageStreamBuffer* image_stream_buffer_      = nullptr;
+  size_t             image_stream_buffer_size_ = 0;
+  void (*image_stream_callback_)(int32_t)      = nullptr;
+  int64_t            image_stream_sequence_    = 0;
+  std::mutex         image_stream_ffi_mutex_;
+
+  struct ImageStreamSlot {
+    std::vector<uint8_t> data;
+    int  width  = 0;
+    int  height = 0;
+    bool dirty  = false;
+  };
+  std::mutex              image_stream_mutex_;
+  std::condition_variable image_stream_cv_;
+  ImageStreamSlot         image_stream_slot_;
+  std::thread             image_stream_thread_;
+  std::atomic<bool>       image_stream_running_{false};
+  std::thread             image_stream_join_thread_;
+  std::mutex              image_stream_thread_mutex_;
+
+  // ── Async dispose ───────────────────────────────────────────────────────
+  std::thread                         dispose_thread_;
+  std::mutex                          dispose_mutex_;
+  std::vector<std::function<void()>>  dispose_callbacks_;
+};
+
+
+