write video frames in separate thread

demo/Makefile

@@ -9,7 +9,7 @@ SDLCONFIG = /home/frank/local/sdl/bin/sdl2-config
 CFLAGS = -Wall -O2 -c -I$(SFW_LIB_DIR) -I$(SFW_SRC_DIR)
 CPP_FLAGS = $(CFLAGS) --std=c++17
 SDL_FLAGS = $(shell $(SDLCONFIG) --cflags)
-LFLAGS = $(shell $(SDLCONFIG) --libs)
+LFLAGS = $(shell $(SDLCONFIG) --libs) -lpthread
 export ANDROID_HOME = /home/frank/ext/software/android-sdk
 export ANDROID_NDK_HOME = /home/frank/ext/software/android-ndk-r8d
 BUILDDIR = build

src/Recorder.cpp

@@ -56,13 +56,20 @@ void Recorder::end_recording()
 {
     std::cout << "Ending recording..." << std::endl;
     animation.reset();
-    SDL_Surface* frame;
     nlohmann::json config = get_configuration();
     fs::path root = config["path"]["video"];
     fs::create_directories(root);
     fs::path directory = sfw::get_next_file_name(root, 5, "video-");
     fs::create_directories(directory);
+    std::function<void(fs::path)> f = std::bind(&Recorder::write_video_frames, this, std::placeholders::_1);
+    std::thread writing(f, directory);
+    writing.detach();
+}
+
+void Recorder::write_video_frames(fs::path directory)
+{
     std::cout << "Writing recording to " << directory << "..." << std::endl;
+    SDL_Surface* frame;
     for (int ii = 0; not frames.empty(); ii++)
     {
         frame = frames.front();
@@ -73,6 +80,7 @@ void Recorder::end_recording()
         frames.erase(frames.begin());
         SDL_FreeSurface(frame);
     }
+    std::cout << "Wrote " << directory << std::endl;
 }
 
 void Recorder::update()

src/Recorder.hpp

@@ -3,6 +3,8 @@
 
 #include <sstream>
 #include <string>
+#include <thread>
+#include <functional>
 
 #include "SDL.h"
 
@@ -29,6 +31,7 @@ struct Recorder : Node
     void start_recording();
     void add_frame_to_video();
     void end_recording();
+    void write_video_frames(fs::path);
     void update();
     std::string get_class_name() { return "Recorder"; }