From 4ebd25171c91415e550bae11b13e1402dc1424eb Mon Sep 17 00:00:00 2001
From: Rachael Alexanderson <eruanna@drdteam.org>
Date: Wed, 1 Mar 2017 09:46:31 -0500
Subject: [PATCH] - Implemented a simple graphics switch. This currently
 affects NVidia Optimus-enabled notebooks only.

---
 src/win32/hardware.cpp     | 33 +++++++++++++++++++++++++++++++++
 wadsrc/static/language.enu |  3 +++
 wadsrc/static/menudef.txt  | 13 ++++++++++++-
 3 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/src/win32/hardware.cpp b/src/win32/hardware.cpp
index 70898ebe5..5a17e90ec 100644
--- a/src/win32/hardware.cpp
+++ b/src/win32/hardware.cpp
@@ -71,8 +71,34 @@ FRenderer *gl_CreateInterface();
 void I_RestartRenderer();
 int currentrenderer = -1;
 int currentcanvas = -1;
+int currentgpuswitch = -1;
 bool changerenderer;
 
+// Optimus/Hybrid switcher
+CUSTOM_CVAR(Int, vid_gpuswitch, 0, CVAR_ARCHIVE | CVAR_GLOBALCONFIG | CVAR_NOINITCALL)
+{
+	if (self != currentgpuswitch)
+	{
+		switch (self)
+		{
+		case 0:
+			Printf("Selecting default GPU...\n");
+			break;
+		case 1:
+			Printf("Selecting high-performance dedicated GPU...\n");
+			break;
+		case 2:
+			Printf("Selecting power-saving integrated GPU...\n");
+			break;
+		default:
+			Printf("Unknown option (%d) - falling back to 'default'\n", *vid_gpuswitch);
+			self = 0;
+			break;
+		}
+		Printf("You must restart " GAMENAME " for this change to take effect.\n");
+	}
+}
+
 // Software OpenGL canvas
 CUSTOM_CVAR(Bool, vid_used3d, true, CVAR_ARCHIVE | CVAR_GLOBALCONFIG | CVAR_NOINITCALL)
 {
@@ -128,6 +154,13 @@ void I_InitGraphics ()
 {
 	UCVarValue val;
 
+	// todo: implement ATI version of this. this only works for nvidia notebooks, for now.
+	currentgpuswitch = vid_gpuswitch;
+	if (currentgpuswitch == 1)
+		putenv("SHIM_MCCOMPAT=0x800000001"); // discrete
+	else if (currentgpuswitch == 2)
+		putenv("SHIM_MCCOMPAT=0x800000000"); // integrated
+
 	// If the focus window is destroyed, it doesn't go back to the active window.
 	// (e.g. because the net pane was up, and a button on it had focus)
 	if (GetFocus() == NULL && GetActiveWindow() == Window)
diff --git a/wadsrc/static/language.enu b/wadsrc/static/language.enu
index 75ef5eb51..85f7ee830 100644
--- a/wadsrc/static/language.enu
+++ b/wadsrc/static/language.enu
@@ -1832,6 +1832,7 @@ DSPLYMNU_DIMCOLOR				= "Dim color";
 DSPLYMNU_MOVEBOB 				= "View bob amount while moving";
 DSPLYMNU_STILLBOB 				= "View bob amount while not moving";
 DSPLYMNU_BOBSPEED				= "Weapon bob speed";
+DSPLYMNU_GPUSWITCH				= "Notebook Switchable GPU";
 
 // HUD Options
 HUDMNU_TITLE					= "HUD Options";
@@ -2359,6 +2360,8 @@ OPTVAL_GL 					= "OpenGL";
 OPTVAL_D3D					= "Direct3D";
 OPTVAL_HWPOLY				= "OpenGL-Accelerated";
 OPTVAL_SWDOOM				= "Doom Software Renderer";
+OPTVAL_DEDICATED			= "High-Performance";
+OPTVAL_INTEGRATED			= "Power-Saving";
 
 // Colors
 C_BRICK					= "\cabrick";
diff --git a/wadsrc/static/menudef.txt b/wadsrc/static/menudef.txt
index ef2032241..2f5bd0d71 100644
--- a/wadsrc/static/menudef.txt
+++ b/wadsrc/static/menudef.txt
@@ -683,6 +683,13 @@ OptionValue Fuzziness
 	2.0, "$OPTVAL_SHADOW"
 }
 
+OptionValue GPUSwitch
+{
+	0.0, "$OPTVAL_DEFAULT"
+	1.0, "$OPTVAL_DEDICATED"
+	2.0, "$OPTVAL_INTEGRATED"	
+}
+
 OptionMenu "OpenGLOptions"
 {
 	Title "$GLMNU_TITLE"
@@ -755,7 +762,11 @@ OptionMenu "VideoOptions"
 	Slider "$DSPLYMNU_MOVEBOB",			"movebob", 0, 1.0, 0.05, 2
 	Slider "$DSPLYMNU_STILLBOB",		"stillbob", 0, 1.0, 0.05, 2
 	Slider "$DSPLYMNU_BOBSPEED",				"wbobspeed", 0, 2.0, 0.1
-
+	IfOption(Windows)
+	{
+		StaticText " "
+		Option "$DSPLYMNU_GPUSWITCH",			vid_gpuswitch, "GPUSwitch"
+	}
 }
 
 //-------------------------------------------------------------------------------------------