From 235bcacc7b8462d00fe17caa8878f43e90f7428b Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Tue, 13 Nov 2018 20:59:39 +0530
Subject: [PATCH] Make the buffer clearing more robust

Now happens immediately after the buffer is swapped. Fixes #1104
---
 kitty/glfw.c    | 7 +++++--
 kitty/shaders.c | 5 -----
 2 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/kitty/glfw.c b/kitty/glfw.c
index 837887bf4..00211e76c 100644
--- a/kitty/glfw.c
+++ b/kitty/glfw.c
@@ -816,8 +816,11 @@ is_mouse_hidden(OSWindow *w) {
 
 
 void
-swap_window_buffers(OSWindow *w) {
-    glfwSwapBuffers(w->handle);
+swap_window_buffers(OSWindow *os_window) {
+    glfwSwapBuffers(os_window->handle);
+    // ensure all pixels are cleared to background color at least once in the
+    // new buffer
+    if (os_window->clear_count++ < 2) blank_os_window(os_window);
 }
 
 void
diff --git a/kitty/shaders.c b/kitty/shaders.c
index 1f3f1c1c3..ae18fb16f 100644
--- a/kitty/shaders.c
+++ b/kitty/shaders.c
@@ -437,11 +437,6 @@ blank_os_window(OSWindow *os_window) {
 bool
 send_cell_data_to_gpu(ssize_t vao_idx, ssize_t gvao_idx, GLfloat xstart, GLfloat ystart, GLfloat dx, GLfloat dy, Screen *screen, OSWindow *os_window) {
     bool changed = false;
-    if (os_window->clear_count < 2) {
-        os_window->clear_count++;
-        blank_os_window(os_window);
-        changed = true;
-    }
     if (os_window->fonts_data) {
         if (cell_prepare_to_render(vao_idx, gvao_idx, screen, xstart, ystart, dx, dy, os_window->fonts_data)) changed = true;
     }