From 3fb00f6c70e2f575357c5812222442c79dead755 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Fri, 28 Jun 2019 18:26:11 +0530
Subject: [PATCH] Re-request render frames if we dont hear back in a quarter of
 a second

Fixes #1748 (I hope)
---
 kitty/child-monitor.c | 7 ++++++-
 kitty/glfw.c          | 2 ++
 kitty/state.h         | 1 +
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/kitty/child-monitor.c b/kitty/child-monitor.c
index ae40c68b9..9ff7e253a 100644
--- a/kitty/child-monitor.c
+++ b/kitty/child-monitor.c
@@ -675,6 +675,11 @@ draw_resizing_text(OSWindow *w) {
     }
 }
 
+static inline bool
+no_render_frame_received_recently(OSWindow *w, double now) {
+    return now - w->last_render_frame_received_at > 0.25;
+}
+
 static inline void
 render(double now) {
     double time_since_last_render = now - last_render_at;
@@ -691,7 +696,7 @@ render(double now) {
             continue;
         }
         if (USE_RENDER_FRAMES && w->render_state != RENDER_FRAME_READY) {
-            if (w->render_state == RENDER_FRAME_NOT_REQUESTED) request_frame_render(w);
+            if (w->render_state == RENDER_FRAME_NOT_REQUESTED || no_render_frame_received_recently(w, now)) request_frame_render(w);
             continue;
         }
         make_os_window_context_current(w);
diff --git a/kitty/glfw.c b/kitty/glfw.c
index 8dbf48529..ed80857cd 100644
--- a/kitty/glfw.c
+++ b/kitty/glfw.c
@@ -1052,6 +1052,7 @@ cocoa_frame_request_callback(GLFWwindow *window) {
     for (size_t i = 0; i < global_state.num_os_windows; i++) {
         if (global_state.os_windows[i].handle == window) {
             global_state.os_windows[i].render_state = RENDER_FRAME_READY;
+            global_state.os_windows[i].last_render_frame_received_at = monotonic();
             request_tick_callback();
             break;
         }
@@ -1071,6 +1072,7 @@ wayland_frame_request_callback(id_type os_window_id) {
     for (size_t i = 0; i < global_state.num_os_windows; i++) {
         if (global_state.os_windows[i].id == os_window_id) {
             global_state.os_windows[i].render_state = RENDER_FRAME_READY;
+            global_state.os_windows[i].last_render_frame_received_at = monotonic();
             request_tick_callback();
             break;
         }
diff --git a/kitty/state.h b/kitty/state.h
index 30e3a481e..617fc36c6 100644
--- a/kitty/state.h
+++ b/kitty/state.h
@@ -148,6 +148,7 @@ typedef struct {
     id_type temp_font_group_id;
     double pending_scroll_pixels;
     enum RENDER_STATE render_state;
+    double last_render_frame_received_at;
     id_type last_focused_counter;
     ssize_t gvao_idx;
 } OSWindow;