From bbc140e020a4490f0505abded5eac63ede6b7c97 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Tue, 21 Nov 2017 17:05:39 +0530
Subject: [PATCH] Only enable GL_BLEND when actually needed

---
 kitty/gl.h      | 4 +---
 kitty/glfw.c    | 4 +---
 kitty/shaders.c | 2 ++
 3 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/kitty/gl.h b/kitty/gl.h
index aefdec151..3cd01a413 100644
--- a/kitty/gl.h
+++ b/kitty/gl.h
@@ -44,10 +44,9 @@ check_for_gl_error(const char *name, void UNUSED *funcptr, int UNUSED len_args,
     }
 }
 
-static bool glad_loaded = false;
-
 void
 gl_init() {
+    static bool glad_loaded = false;
     if (!glad_loaded) {
         if (!init_glad((GLADloadproc) glfwGetProcAddress, global_state.debug_gl)) {
             fatal("Loading the OpenGL library failed");
@@ -61,7 +60,6 @@ gl_init() {
 #undef ARB_TEST
         glad_loaded = true;
     }
-    glEnable(GL_BLEND);
 }
 
 void
diff --git a/kitty/glfw.c b/kitty/glfw.c
index aad92d88b..509f313b2 100644
--- a/kitty/glfw.c
+++ b/kitty/glfw.c
@@ -209,8 +209,6 @@ create_os_window(PyObject UNUSED *self, PyObject *args) {
         glfwWindowHint(GLFW_SAMPLES, 0);
 #ifdef __APPLE__
         if (OPT(macos_hide_titlebar)) glfwWindowHint(GLFW_DECORATED, false);
-        // OS X cannot handle 16bit stencil buffers
-        glfwWindowHint(GLFW_STENCIL_BITS, 8);
 #endif
 
         standard_cursor = glfwCreateStandardCursor(GLFW_IBEAM_CURSOR);
@@ -238,8 +236,8 @@ create_os_window(PyObject UNUSED *self, PyObject *args) {
     if (x != -1 && y != -1) glfwSetWindowPos(glfw_window, x, y);
     current_os_window_ctx = glfw_window;
     glfwSwapInterval(swap_interval);  // a value of 1 makes mouse selection laggy
-    gl_init();
     if (is_first_window) { 
+        gl_init();
         PyObject *ret = PyObject_CallFunction(load_programs, NULL);
         if (ret == NULL) return NULL;
         Py_DECREF(ret);
diff --git a/kitty/shaders.c b/kitty/shaders.c
index 9000bc26b..4ffb925d4 100644
--- a/kitty/shaders.c
+++ b/kitty/shaders.c
@@ -308,6 +308,7 @@ draw_all_cells(ssize_t vao_idx, ssize_t gvao_idx, Screen *screen) {
 
 static void
 draw_cells_interleaved(ssize_t vao_idx, ssize_t gvao_idx, Screen *screen) {
+    glEnable(GL_BLEND);
     bind_program(CELL_BACKGROUND_PROGRAM); 
     glDrawArraysInstanced(GL_TRIANGLE_FAN, 0, 4, screen->lines * screen->columns); 
 
@@ -321,6 +322,7 @@ draw_cells_interleaved(ssize_t vao_idx, ssize_t gvao_idx, Screen *screen) {
     glDrawArraysInstanced(GL_TRIANGLE_FAN, 0, 4, screen->lines * screen->columns); 
 
     if (screen->grman->num_of_positive_refs) draw_graphics(vao_idx, gvao_idx, screen->grman->render_data, screen->grman->num_of_negative_refs, screen->grman->num_of_positive_refs);
+    glDisable(GL_BLEND);
 }
 
 void