From db9ee23a86766d48e65d5f2df96801829b50d7dd Mon Sep 17 00:00:00 2001
From: UnknownShadow200 <unknownshadow200@gmail.com>
Date: Sun, 28 Nov 2021 21:58:48 +1100
Subject: [PATCH] OpenGL: Go into reduced performance mode when window is
 obscured

---
 src/Window.h         |  3 +++
 src/Window_Android.c |  2 ++
 src/Window_Carbon.c  |  2 ++
 src/Window_SDL.c     |  2 ++
 src/Window_Web.c     |  2 ++
 src/Window_Win.c     |  2 ++
 src/Window_X11.c     |  2 ++
 src/_GLShared.h      | 10 +++++++++-
 src/interop_cocoa.m  |  2 ++
 src/interop_ios.m    |  1 +
 10 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/src/Window.h b/src/Window.h
index 480ebd870..b8bfef7f3 100644
--- a/src/Window.h
+++ b/src/Window.h
@@ -103,6 +103,9 @@ int Window_GetWindowState(void);
 cc_result Window_EnterFullscreen(void);
 /* Attempts to restore the window to before it entered full screen. */
 cc_result Window_ExitFullscreen(void);
+/* Returns non-zero if the window is obscured (occluded or minimised) */
+/* NOTE: Not supported by all windowing backends */
+int Window_IsObscured(void);
 
 /* Makes the window visible and focussed on screen. */
 void Window_Show(void);
diff --git a/src/Window_Android.c b/src/Window_Android.c
index a0435b1c9..04b21f3d9 100644
--- a/src/Window_Android.c
+++ b/src/Window_Android.c
@@ -322,6 +322,8 @@ cc_result Window_ExitFullscreen(void) {
 	return 0; 
 }
 
+int Window_IsObscured(void) { return 0; }
+
 void Window_Show(void) { } /* Window already visible */
 void Window_SetSize(int width, int height) { }
 
diff --git a/src/Window_Carbon.c b/src/Window_Carbon.c
index 34c09d6da..47f5bf93e 100644
--- a/src/Window_Carbon.c
+++ b/src/Window_Carbon.c
@@ -543,6 +543,8 @@ cc_result Window_ExitFullscreen(void) {
 	return res;
 }
 
+int Window_IsObscured(void) { return 0; }
+
 void Window_Show(void) {
 	ShowWindow(win_handle);
 	/* TODO: Do we actually need to reposition */
diff --git a/src/Window_SDL.c b/src/Window_SDL.c
index d4193ea3c..720415ee8 100644
--- a/src/Window_SDL.c
+++ b/src/Window_SDL.c
@@ -83,6 +83,8 @@ cc_result Window_EnterFullscreen(void) {
 }
 cc_result Window_ExitFullscreen(void) { SDL_RestoreWindow(win_handle); return 0; }
 
+int Window_IsObscured(void) { return 0; }
+
 void Window_Show(void) { SDL_ShowWindow(win_handle); }
 
 void Window_SetSize(int width, int height) {
diff --git a/src/Window_Web.c b/src/Window_Web.c
index 22e351d22..7eb14d503 100644
--- a/src/Window_Web.c
+++ b/src/Window_Web.c
@@ -466,6 +466,8 @@ cc_result Window_ExitFullscreen(void) {
 	return 0;
 }
 
+int Window_IsObscured(void) { return 0; }
+
 void Window_Show(void) { }
 
 void Window_SetSize(int width, int height) {
diff --git a/src/Window_Win.c b/src/Window_Win.c
index 040370bdb..2c4792850 100644
--- a/src/Window_Win.c
+++ b/src/Window_Win.c
@@ -447,6 +447,8 @@ cc_result Window_ExitFullscreen(void) {
 	return 0;
 }
 
+int Window_IsObscured(void) { return 0; }
+
 void Window_Show(void) {
 	ShowWindow(win_handle, SW_SHOW);
 	BringWindowToTop(win_handle);
diff --git a/src/Window_X11.c b/src/Window_X11.c
index fd206188c..234d2f848 100644
--- a/src/Window_X11.c
+++ b/src/Window_X11.c
@@ -433,6 +433,8 @@ cc_result Window_ExitFullscreen(void) {
 	ToggleFullscreen(_NET_WM_STATE_REMOVE); return 0;
 }
 
+int Window_IsObscured(void) { return 0; }
+
 void Window_Show(void) { XMapWindow(win_display, win_handle); }
 
 void Window_SetSize(int width, int height) {
diff --git a/src/_GLShared.h b/src/_GLShared.h
index 293bb5d82..231744a60 100644
--- a/src/_GLShared.h
+++ b/src/_GLShared.h
@@ -275,7 +275,15 @@ void Gfx_SetFpsLimit(cc_bool vsync, float minFrameMs) {
 void Gfx_BeginFrame(void) { frameStart = Stopwatch_Measure(); }
 void Gfx_Clear(void) { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); }
 
-void Gfx_EndFrame(void) { 
+void Gfx_EndFrame(void) {
+#ifndef CC_BUILD_GLMODERN
+	if (Window_IsObscured()) {
+		TickReducedPerformance();
+	} else {
+		EndReducedPerformance();
+	}
+#endif
+
 	if (!GLContext_SwapBuffers()) Gfx_LoseContext("GLContext lost");
 	if (gfx_minFrameMs) LimitFPS();
 }
diff --git a/src/interop_cocoa.m b/src/interop_cocoa.m
index 98737939f..6e24efd73 100644
--- a/src/interop_cocoa.m
+++ b/src/interop_cocoa.m
@@ -323,6 +323,8 @@ cc_result Window_ExitFullscreen(void) {
 	return 0;
 }
 
+int Window_IsObscured(void) { return 0; }
+
 void Window_Show(void) { 
 	[winHandle makeKeyAndOrderFront:appHandle];
 	RefreshWindowBounds(); // TODO: even necessary?
diff --git a/src/interop_ios.m b/src/interop_ios.m
index 254437453..4646c6351 100644
--- a/src/interop_ios.m
+++ b/src/interop_ios.m
@@ -248,6 +248,7 @@ void Window_CloseKeyboard(void) {
 int Window_GetWindowState(void) { return WINDOW_STATE_NORMAL; }
 cc_result Window_EnterFullscreen(void) { return ERR_NOT_SUPPORTED; }
 cc_result Window_ExitFullscreen(void) { return ERR_NOT_SUPPORTED; }
+int Window_IsObscured(void) { return 0; }
 
 void Window_EnableRawMouse(void)  { }
 void Window_UpdateRawMouse(void)  { }