From 9dc29a75b416c6dab27ce93d0129383309cbf2c2 Mon Sep 17 00:00:00 2001
From: HybridDog <3192173+HybridDog@users.noreply.github.com>
Date: Sat, 3 Oct 2020 18:33:51 +0200
Subject: Reduce the FPS when the window is unfocused (#8837)

---
 src/client/game.cpp     |  7 ++++---
 src/defaultsettings.cpp |  4 ++--
 src/gui/guiEngine.cpp   | 17 +++++++++--------
 src/gui/guiEngine.h     |  2 +-
 4 files changed, 16 insertions(+), 14 deletions(-)

(limited to 'src')

diff --git a/src/client/game.cpp b/src/client/game.cpp
index 920383aaf..8f9d51417 100644
--- a/src/client/game.cpp
+++ b/src/client/game.cpp
@@ -3996,9 +3996,10 @@ inline void Game::limitFps(FpsControl *fps_timings, f32 *dtime)
 	else
 		fps_timings->busy_time = 0;
 
-	u32 frametime_min = 1000 / (g_menumgr.pausesGame()
-			? g_settings->getFloat("pause_fps_max")
-			: g_settings->getFloat("fps_max"));
+	u32 frametime_min = 1000 / (
+		device->isWindowFocused() && !g_menumgr.pausesGame()
+			? g_settings->getFloat("fps_max")
+			: g_settings->getFloat("fps_max_unfocused"));
 
 	if (fps_timings->busy_time < frametime_min) {
 		fps_timings->sleep_time = frametime_min - fps_timings->busy_time;
diff --git a/src/defaultsettings.cpp b/src/defaultsettings.cpp
index 3a0b88dc2..8f5ed3e17 100644
--- a/src/defaultsettings.cpp
+++ b/src/defaultsettings.cpp
@@ -165,7 +165,7 @@ void set_default_settings(Settings *settings)
 	settings->setDefault("tooltip_show_delay", "400");
 	settings->setDefault("tooltip_append_itemname", "false");
 	settings->setDefault("fps_max", "60");
-	settings->setDefault("pause_fps_max", "20");
+	settings->setDefault("fps_max_unfocused", "20");
 	settings->setDefault("viewing_range", "100");
 #if ENABLE_GLES
 	settings->setDefault("near_plane", "0.1");
@@ -477,7 +477,7 @@ void set_default_settings(Settings *settings)
 	settings->setDefault("max_block_generate_distance", "5");
 	settings->setDefault("enable_3d_clouds", "false");
 	settings->setDefault("fps_max", "30");
-	settings->setDefault("pause_fps_max", "10");
+	settings->setDefault("fps_max_unfocused", "10");
 	settings->setDefault("max_objects_per_block", "20");
 	settings->setDefault("sqlite_synchronous", "1");
 	settings->setDefault("server_map_save_interval", "15");
diff --git a/src/gui/guiEngine.cpp b/src/gui/guiEngine.cpp
index b40707d01..4a13f0b11 100644
--- a/src/gui/guiEngine.cpp
+++ b/src/gui/guiEngine.cpp
@@ -297,10 +297,14 @@ void GUIEngine::run()
 
 		driver->endScene();
 
+		IrrlichtDevice *device = RenderingEngine::get_raw_device();
+		u32 frametime_min = 1000 / (device->isWindowFocused()
+			? g_settings->getFloat("fps_max")
+			: g_settings->getFloat("fps_max_unfocused"));
 		if (m_clouds_enabled)
-			cloudPostProcess();
+			cloudPostProcess(frametime_min, device);
 		else
-			sleep_ms(25);
+			sleep_ms(frametime_min);
 
 		m_script->step();
 
@@ -367,9 +371,8 @@ void GUIEngine::cloudPreProcess()
 }
 
 /******************************************************************************/
-void GUIEngine::cloudPostProcess()
+void GUIEngine::cloudPostProcess(u32 frametime_min, IrrlichtDevice *device)
 {
-	float fps_max = g_settings->getFloat("pause_fps_max");
 	// Time of frame without fps limit
 	u32 busytime_u32;
 
@@ -380,12 +383,10 @@ void GUIEngine::cloudPostProcess()
 	else
 		busytime_u32 = 0;
 
-	// FPS limiter
-	u32 frametime_min = 1000./fps_max;
-
+	// FPS limit
 	if (busytime_u32 < frametime_min) {
 		u32 sleeptime = frametime_min - busytime_u32;
-		RenderingEngine::get_raw_device()->sleep(sleeptime);
+		device->sleep(sleeptime);
 	}
 }
 
diff --git a/src/gui/guiEngine.h b/src/gui/guiEngine.h
index f9ad0fb0a..e5b3edce7 100644
--- a/src/gui/guiEngine.h
+++ b/src/gui/guiEngine.h
@@ -277,7 +277,7 @@ private:
 	/** do preprocessing for cloud subsystem */
 	void cloudPreProcess();
 	/** do postprocessing for cloud subsystem */
-	void cloudPostProcess();
+	void cloudPostProcess(u32 frametime_min, IrrlichtDevice *device);
 
 	/** internam data required for drawing clouds */
 	struct clouddata {
-- 
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