[feat] use SDL_WaitEventTimeout to refresh frames and reduce CPU usage

src/single_window/render.cpp

@@ -982,8 +982,12 @@ void Render::MainLoop() {
       CreateConnectionPeer();
     }
 
+    SDL_Event event;
+    if (SDL_WaitEventTimeout(&event, sdl_refresh_ms_)) {
+      ProcessSdlEvent(event);
+    }
+
     UpdateLabels();
-    ProcessSdlEvent();
     HandleRecentConnections();
     HandleStreamWindow();
 
@@ -1229,9 +1233,7 @@ void Render::UpdateRenderRect() {
   }
 }
 
-void Render::ProcessSdlEvent() {
-  SDL_Event event;
-  while (SDL_PollEvent(&event)) {
+void Render::ProcessSdlEvent(const SDL_Event& event) {
   if (main_ctx_) {
     ImGui::SetCurrentContext(main_ctx_);
     ImGui_ImplSDL3_ProcessEvent(&event);
@@ -1340,18 +1342,18 @@ void Render::ProcessSdlEvent() {
         ProcessMouseEvent(event);
       }
       break;
-    }
 
+    default:
       if (event.type == STREAM_REFRESH_EVENT) {
         auto* props = static_cast<SubStreamWindowProperties*>(event.user.data1);
         if (!props) {
-        continue;
+          break;
         }
         if (props->video_width_ <= 0 || props->video_height_ <= 0) {
-        continue;
+          break;
         }
         if (!props->dst_buffer_) {
-        continue;
+          break;
         }
 
         // use libyuv to convert NV12 to ARGB in order to fix SDL3 NV12 texture
@@ -1363,10 +1365,10 @@ void Render::ProcessSdlEvent() {
             props->texture_height_ = props->video_height_;
 
             SDL_DestroyTexture(props->stream_texture_);
-          props->stream_texture_ =
-              SDL_CreateTexture(stream_renderer_, SDL_PIXELFORMAT_ARGB8888,
-                                SDL_TEXTUREACCESS_STREAMING,
-                                props->texture_width_, props->texture_height_);
+            props->stream_texture_ = SDL_CreateTexture(
+                stream_renderer_, SDL_PIXELFORMAT_ARGB8888,
+                SDL_TEXTUREACCESS_STREAMING, props->texture_width_,
+                props->texture_height_);
           }
         } else {
           props->texture_width_ = props->video_width_;
@@ -1398,7 +1400,7 @@ void Render::ProcessSdlEvent() {
 
         SDL_UpdateTexture(props->stream_texture_, NULL, props->argb_buffer_,
                           static_cast<int>(argb_stride));
+      }
       break;
   }
 }
-}

src/single_window/render.h

@@ -138,7 +138,7 @@ class Render {
   void CleanSubStreamWindowProperties(
       std::shared_ptr<SubStreamWindowProperties> props);
   void UpdateRenderRect();
-  void ProcessSdlEvent();
+  void ProcessSdlEvent(const SDL_Event &event);
 
  private:
   int CreateStreamRenderWindow();
@@ -213,7 +213,7 @@ class Render {
 
  private:
   int SendKeyCommand(int key_code, bool is_down);
-  int ProcessMouseEvent(SDL_Event &event);
+  int ProcessMouseEvent(const SDL_Event &event);
 
   static void SdlCaptureAudioIn(void *userdata, Uint8 *stream, int len);
   static void SdlCaptureAudioOut(void *userdata, Uint8 *stream, int len);
@@ -290,6 +290,7 @@ class Render {
   SDL_Renderer *main_renderer_ = nullptr;
   ImGuiContext *main_ctx_ = nullptr;
   bool exit_ = false;
+  const int sdl_refresh_ms_ = 16;  // ~60 FPS
 
   // main window properties
   bool start_mouse_controller_ = false;

src/single_window/render_callback_func.cpp

@@ -35,7 +35,7 @@ int Render::SendKeyCommand(int key_code, bool is_down) {
   return 0;
 }
 
-int Render::ProcessMouseEvent(SDL_Event &event) {
+int Render::ProcessMouseEvent(const SDL_Event &event) {
   controlled_remote_id_ = "";
   int video_width, video_height = 0;
   int render_width, render_height = 0;