restore multithreading on iOS and use DisplayLink to decouple rendering from the main loop

PanoPainter/GameViewController.h

@@ -21,6 +21,7 @@
     >
 {
 @public GameView* glview;
+@public CADisplayLink *displayLink;
 }
 - (void)display_file:(std::string)filename;
 - (void)reset_touch;
@@ -32,4 +33,6 @@
 - (void)unregisterForKeyboardNotifications;
 - (void)crash;
 - (void)share_file:(NSString*)file_path;
+- (void)tick;
+- (void)render_loop;
 @end

PanoPainter/GameViewController.m

@@ -14,6 +14,8 @@
 
 std::deque<std::packaged_task<void()>> tasklist;
 std::mutex task_mutex;
+std::mutex render_mutex;
+std::condition_variable render_cv;
 
 @interface GameImagePicker : UIImagePickerController
 {
@@ -432,13 +434,14 @@ std::set<UITouch*> ignored_touch;
     return YES;
 }
 
-- (void)setupGL
+-(void)tick
 {
-    [self async_lock];
-    App::I.init();
-    [self async_unlock];
+    //std::lock_guard<std::mutex> lock(render_mutex);
+    render_cv.notify_one();
+}
 
-    std::thread([self]{
+-(void)render_loop
+{
     while (true)
     {
         static auto time = std::chrono::steady_clock::now();
@@ -450,7 +453,7 @@ std::set<UITouch*> ignored_touch;
         elapsed += dt.count();
         min_fps_timer += dt.count();
 
-            if (min_fps_timer > 0.1)
+        if (min_fps_timer > 0.5)
         {
             App::I.redraw = true;
             min_fps_timer = 0;
@@ -465,15 +468,16 @@ std::set<UITouch*> ignored_touch;
 
         App::I.tick(dt.count());
 
-            [self async_lock];
         if (!(App::I.redraw || App::I.animate || !working_list.empty()))
         {
             //[self.context presentRenderbuffer:GL_FRAMEBUFFER];
-                [self async_unlock];
-                std::this_thread::sleep_for(std::chrono::milliseconds(100));
+            //[self async_unlock];
+            std::unique_lock<std::mutex> lock(render_mutex);
+            render_cv.wait(lock);
             continue;
         }
 
+        [self async_lock];
         while (!working_list.empty())
         {
             working_list.front()();
@@ -486,7 +490,21 @@ std::set<UITouch*> ignored_touch;
         [self->glview display];
         elapsed = 0;
     }
+}
+
+- (void)setupGL
+{
+    [self async_lock];
+    App::I.init();
+    [self async_unlock];
+    
+    std::thread([self]{
+        [self render_loop];
     }).detach();
+    
+    displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(tick)];
+    displayLink.frameInterval = 4;
+    [displayLink addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
 }
 
 - (void)tearDownGL

src/canvas.cpp

@@ -1176,10 +1176,6 @@ void Canvas::clear_context()
 
 void Canvas::import_equirectangular(std::string file_path)
 {
-#if __IOS__
-    import_equirectangular_thread(file_path);
-    return;
-#endif
     std::thread t(&Canvas::import_equirectangular_thread, this, file_path);
     t.detach();
 }
@@ -1253,12 +1249,6 @@ void Canvas::export_equirectangular(std::string file_path, std::function<void()>
 {
     if (App::I.check_license())
     {
-#if __IOS__
-        export_equirectangular_thread(file_path);
-        if (on_complete)
-            on_complete();
-        return;
-#endif
         std::thread t([=] {
             export_equirectangular_thread(file_path);
             if (on_complete)
@@ -1563,12 +1553,6 @@ void Canvas::export_layers(std::string file_name, std::function<void()> on_compl
 {
     if (App::I.check_license())
     {
-#if __IOS__
-        export_layers_thread(file_name);
-        if (on_complete)
-            on_complete();
-        return;
-#endif
         std::thread t([=] {
             export_layers_thread(file_name);
             if (on_complete)
@@ -1824,12 +1808,6 @@ void Canvas::project_save(std::function<void(bool)> on_complete)
 {
     if (App::I.check_license())
     {
-#if __IOS__
-        bool ret = project_save_thread(App::I.doc_path);
-        if (on_complete)
-            on_complete(ret);
-        return;
-#endif
         std::thread t([=] {
             bool ret = project_save_thread(App::I.doc_path);
             if (on_complete)
@@ -1844,12 +1822,6 @@ void Canvas::project_save(std::string file_path, std::function<void(bool)> on_co
     LOG("saving %s", file_path.c_str());
     if (App::I.check_license())
     {
-#if __IOS__
-        bool ret = project_save_thread(file_path);
-        if (on_complete)
-            on_complete(ret);
-        return;
-#endif
         std::thread t([=] {
             bool ret = project_save_thread(file_path);
             if (on_complete)
@@ -2046,12 +2018,6 @@ bool Canvas::project_save_thread(std::string file_path)
 
 void Canvas::project_open(std::string file_path, std::function<void(bool)> on_complete)
 {
-#if __IOS__
-    bool ret = project_open_thread(file_path);
-    if (on_complete)
-        on_complete(ret);
-    return;
-#endif
     std::thread t([=] {
         bool result = project_open_thread(file_path);
         if (on_complete)

src/node_stroke_preview.cpp

@@ -492,6 +492,7 @@ void NodeStrokePreview::draw_stroke()
                     gl.save();
                     node->draw_stroke_immediate();
                     gl.restore();
+                    node->app_redraw();
                     node->async_end();
                     std::this_thread::sleep_for(std::chrono::milliseconds(30));
                 }