wayland: always be sure to initially try to render

A subtle regression from c26d833. On sway if mpv was set to be a
floating window in the config, set_buffer_scale would actually get
applied twice according to the wayland log. That meant a 1920x1080
window would appear as a 960x540 window if the scale of the wl_output
was set to 2. This only affected egl on sway (didn't occur on weston and
was too lazy to try anything else; probably they were fine). Since
wl->render is initially false, that meant that the very first run
through the render loop returns false. This probably caused something
weird to happen with the set_buffer_scale calls (the egl window gets
created and everything but mpv doesn't write to it just yet) which makes
the set_buffer_scale call happen an extra time. Since it was always
intended for mpv to initally render, this is worth fixing. Just chnage
wl->render to wl->hidden (again) and flip the bools around. That way,
the initial false value results in render == true and mpv tries to draw
on the first pass. This fixes the weird scaling behavior because
reasons.

video/out/opengl/context_wayland.c

@@ -60,7 +60,7 @@ static bool wayland_egl_start_frame(struct ra_swapchain *sw, struct ra_fbo *out_
 {
     struct ra_ctx *ctx = sw->ctx;
     struct vo_wayland_state *wl = ctx->vo->wl;
-    bool render = wl->render || wl->opts->disable_vsync;
+    bool render = !wl->hidden || wl->opts->disable_vsync;
     wl->frame_wait = true;
 
     return render ? ra_gl_ctx_start_frame(sw, out_fbo) : false;

video/out/vo_wlshm.c

@@ -218,7 +218,7 @@ static void draw_image(struct vo *vo, struct mp_image *src)
     struct priv *p = vo->priv;
     struct vo_wayland_state *wl = vo->wl;
     struct buffer *buf;
-    bool render = wl->render || wl->opts->disable_vsync;
+    bool render = !wl->hidden || wl->opts->disable_vsync;
     wl->frame_wait = true;
 
     if (!render)

video/out/vulkan/context_wayland.c

@@ -29,7 +29,7 @@ struct priv {
 static bool wayland_vk_start_frame(struct ra_ctx *ctx)
 {
     struct vo_wayland_state *wl = ctx->vo->wl;
-    bool render = wl->render || wl->opts->disable_vsync;
+    bool render = !wl->hidden || wl->opts->disable_vsync;
     wl->frame_wait = true;
 
     return render;

video/out/wayland_common.c

@@ -1964,18 +1964,17 @@ void vo_wayland_wait_frame(struct vo_wayland_state *wl)
     if (wl->frame_wait) {
         // Only consider consecutive missed callbacks.
         if (wl->timeout_count > 1) {
-            wl->render = false;
+            wl->hidden = true;
             return;
         } else {
             wl->timeout_count += 1;
-            wl->render = true;
+            wl->hidden = false;
             return;
         }
     }
 
     wl->timeout_count = 0;
-    wl->render = true;
-    return;
+    wl->hidden = false;
 }
 
 void vo_wayland_wait_events(struct vo *vo, int64_t until_time_us)

video/out/wayland_common.h

@@ -58,7 +58,7 @@ struct vo_wayland_state {
     bool has_keyboard_input;
     bool focused;
     bool frame_wait;
-    bool render;
+    bool hidden;
     bool state_change;
     bool toplevel_configured;
     int display_fd;