Open the scrcpy window earlier

Previously, the window was opened only once the first frame was
available. Instead, open it as soon as the frame dimensions are known.

This is especially useful when the encoder does not produce an initial
frame while the phone is turned off (e.g., with --no-power-on).

Fixes #6546 <https://github.com/Genymobile/scrcpy/issues/6546>

app/src/events.h

@@ -9,6 +9,7 @@
 
 enum {
     SC_EVENT_NEW_FRAME = SDL_EVENT_USER,
+    SC_EVENT_OPEN_WINDOW,
     SC_EVENT_RUN_ON_MAIN_THREAD,
     SC_EVENT_DEVICE_DISCONNECTED,
     SC_EVENT_SERVER_CONNECTION_FAILED,

app/src/screen.c

@@ -210,7 +210,6 @@ sc_screen_render(struct sc_screen *screen, bool update_content_rect) {
     bool ok = false;
     SDL_Texture *texture = screen->tex.texture;
     if (!texture) {
-        LOGW("No texture to render");
         goto end;
     }
 
@@ -280,10 +279,8 @@ sc_screen_frame_sink_open(struct sc_frame_sink *sink,
                           const AVCodecContext *ctx,
                           const struct sc_stream_session *session) {
     assert(ctx->pix_fmt == AV_PIX_FMT_YUV420P);
-    (void) session;
 
     struct sc_screen *screen = DOWNCAST(sink);
-    (void) screen;
 
     if (ctx->width <= 0 || ctx->width > 0xFFFF
             || ctx->height <= 0 || ctx->height > 0xFFFF) {
@@ -291,6 +288,19 @@ sc_screen_frame_sink_open(struct sc_frame_sink *sink,
         return false;
     }
 
+    // content_size can be written from this thread, because it is never read
+    // from the main thread before handling SC_EVENT_OPEN_WINDOW (which acts as
+    // a synchronization point) when video is enabled
+    screen->frame_size.width = session->video.width;
+    screen->frame_size.height = session->video.height;
+    screen->content_size = get_oriented_size(screen->frame_size,
+                                             screen->orientation);
+
+    bool ok = sc_push_event(SC_EVENT_OPEN_WINDOW);
+    if (!ok) {
+        return false;
+    }
+
 #ifndef NDEBUG
     screen->open = true;
 #endif
@@ -340,7 +350,6 @@ bool
 sc_screen_init(struct sc_screen *screen,
                const struct sc_screen_params *params) {
     screen->resize_pending = false;
-    screen->has_frame = false;
     screen->window_shown = false;
     screen->paused = false;
     screen->resume_frame = NULL;
@@ -694,14 +703,14 @@ sc_screen_set_orientation(struct sc_screen *screen,
 static bool
 sc_screen_apply_frame(struct sc_screen *screen) {
     assert(screen->video);
+    assert(screen->window_shown);
 
     sc_fps_counter_add_rendered_frame(&screen->fps_counter);
 
     AVFrame *frame = screen->frame;
     struct sc_size new_frame_size = {frame->width, frame->height};
 
-    if (!screen->has_frame
-            || screen->frame_size.width != new_frame_size.width
+    if (screen->frame_size.width != new_frame_size.width
             || screen->frame_size.height != new_frame_size.height) {
 
         // frame dimension changed
@@ -709,14 +718,8 @@ sc_screen_apply_frame(struct sc_screen *screen) {
 
         struct sc_size new_content_size =
             get_oriented_size(new_frame_size, screen->orientation);
-        if (screen->has_frame) {
-            set_content_size(screen, new_content_size);
-            sc_screen_update_content_rect(screen);
-        } else {
-            // This is the first frame
-            screen->has_frame = true;
-            screen->content_size = new_content_size;
-        }
+        set_content_size(screen, new_content_size);
+        sc_screen_update_content_rect(screen);
     }
 
     bool ok = sc_texture_set_from_frame(&screen->tex, frame);
@@ -724,17 +727,6 @@ sc_screen_apply_frame(struct sc_screen *screen) {
         return false;
     }
 
-    assert(screen->has_frame);
-    if (!screen->window_shown) {
-        // this is the very first frame, show the window
-        sc_screen_show_initial_window(screen);
-
-        if (sc_screen_is_relative_mode(screen)) {
-            // Capture mouse on start
-            sc_mouse_capture_set_active(&screen->mc, true);
-        }
-    }
-
     sc_screen_render(screen, false);
     return true;
 }
@@ -856,6 +848,16 @@ sc_screen_resize_to_pixel_perfect(struct sc_screen *screen) {
 void
 sc_screen_handle_event(struct sc_screen *screen, const SDL_Event *event) {
     switch (event->type) {
+        case SC_EVENT_OPEN_WINDOW:
+            sc_screen_show_initial_window(screen);
+
+            if (sc_screen_is_relative_mode(screen)) {
+                // Capture mouse on start
+                sc_mouse_capture_set_active(&screen->mc, true);
+            }
+
+            sc_screen_render(screen, false);
+            return;
         case SC_EVENT_NEW_FRAME: {
             bool ok = sc_screen_update_frame(screen);
             if (!ok) {

app/src/screen.h

@@ -70,7 +70,6 @@ struct sc_screen {
     enum sc_orientation orientation;
     // rectangle of the content (excluding black borders)
     struct SDL_FRect rect;
-    bool has_frame;
     bool window_shown;
 
     AVFrame *frame;