From cac5f9d1714676f53fbe0f35531db17a3bc9ebfd Mon Sep 17 00:00:00 2001
From: Jaime Passos <lazymyuutsu@gmail.com>
Date: Mon, 17 Feb 2020 12:14:51 -0300
Subject: [PATCH] add -nogl parm

---
 src/d_main.c      |  9 ++++++++-
 src/m_menu.c      | 28 ++++++++++++++++++++++++++--
 src/screen.c      | 14 ++++++++++++++
 src/sdl/i_video.c | 11 +++++++----
 4 files changed, 55 insertions(+), 7 deletions(-)

diff --git a/src/d_main.c b/src/d_main.c
index 6616dfaa6..d9f67675c 100644
--- a/src/d_main.c
+++ b/src/d_main.c
@@ -1291,11 +1291,18 @@ void D_SRB2Main(void)
 	// Lactozilla: Does the render mode need to change?
 	if ((setrenderneeded != 0) && (setrenderneeded != rendermode))
 	{
-		CONS_Printf("Switching the renderer...\n");
+		CONS_Printf(M_GetText("Switching the renderer...\n"));
+		Z_PreparePatchFlush();
+
+		// set needpatchflush / needpatchrecache true for D_CheckRendererState
 		needpatchflush = true;
 		needpatchrecache = true;
+
+		// Set cv_renderer to the new render mode
 		VID_CheckRenderer();
 		SCR_ChangeRendererCVars(setrenderneeded);
+
+		// check the renderer's state, and then clear setrenderneeded
 		D_CheckRendererState();
 		setrenderneeded = 0;
 	}
diff --git a/src/m_menu.c b/src/m_menu.c
index 97c04ebd5..0349ed3bc 100644
--- a/src/m_menu.c
+++ b/src/m_menu.c
@@ -310,6 +310,7 @@ static void M_AssignJoystick(INT32 choice);
 static void M_ChangeControl(INT32 choice);
 
 // Video & Sound
+static void M_VideoOptions(INT32 choice);
 menu_t OP_VideoOptionsDef, OP_VideoModeDef, OP_ColorOptionsDef;
 #ifdef HWRENDER
 static void M_OpenGLOptionsMenu(void);
@@ -1031,7 +1032,7 @@ static menuitem_t OP_MainMenu[] =
 	{IT_SUBMENU | IT_STRING, NULL, "Player 2 Controls...", &OP_P2ControlsDef,   20},
 	{IT_CVAR    | IT_STRING, NULL, "Controls per key",     &cv_controlperkey,   30},
 
-	{IT_SUBMENU | IT_STRING, NULL, "Video Options...",     &OP_VideoOptionsDef, 50},
+	{IT_CALL    | IT_STRING, NULL, "Video Options...",     M_VideoOptions,      50},
 	{IT_SUBMENU | IT_STRING, NULL, "Sound Options...",     &OP_SoundOptionsDef, 60},
 
 	{IT_CALL    | IT_STRING, NULL, "Server Options...",    M_ServerOptions,     80},
@@ -1282,6 +1283,16 @@ static menuitem_t OP_Camera2ExtendedOptionsMenu[] =
 	{IT_STRING  | IT_CVAR, NULL, "Crosshair", &cv_crosshair2, 126},
 };
 
+enum
+{
+	op_video_resolution = 1,
+#if (defined (__unix__) && !defined (MSDOS)) || defined (UNIXCOMMON) || defined (HAVE_SDL)
+	op_video_fullscreen,
+#endif
+	op_video_vsync,
+	op_video_renderer,
+};
+
 static menuitem_t OP_VideoOptionsMenu[] =
 {
 	{IT_HEADER, NULL, "Screen", NULL, 0},
@@ -2078,6 +2089,20 @@ menu_t OP_PlaystyleDef = {
 	0, 0, 0, NULL
 };
 
+static void M_VideoOptions(INT32 choice)
+{
+	(void)choice;
+#ifdef HWRENDER
+	if (hwrenderloaded == -1)
+	{
+		OP_VideoOptionsMenu[op_video_renderer].status = (IT_TRANSTEXT | IT_PAIR);
+		OP_VideoOptionsMenu[op_video_renderer].patch = "Renderer";
+		OP_VideoOptionsMenu[op_video_renderer].text = "Software";
+	}
+
+#endif
+	M_SetupNextMenu(&OP_VideoOptionsDef);
+}
 
 menu_t OP_VideoOptionsDef =
 {
@@ -12005,7 +12030,6 @@ static void M_VideoModeMenu(INT32 choice)
 
 static void M_DrawMainVideoMenu(void)
 {
-
 	M_DrawGenericScrollMenu();
 	if (itemOn < 8) // where it starts to go offscreen; change this number if you change the layout of the video menu
 	{
diff --git a/src/screen.c b/src/screen.c
index 9c1af11a8..9c61f5689 100644
--- a/src/screen.c
+++ b/src/screen.c
@@ -450,6 +450,20 @@ static int target_renderer = 0;
 void SCR_ActuallyChangeRenderer(void)
 {
 	setrenderneeded = target_renderer;
+
+#ifdef HWRENDER
+	// Well, it didn't even load anyway.
+	if ((hwrenderloaded == -1) && (setrenderneeded == render_opengl))
+	{
+		if (M_CheckParm("-nogl"))
+			CONS_Alert(CONS_ERROR, "OpenGL rendering was disabled!\n");
+		else
+			CONS_Alert(CONS_ERROR, "OpenGL never loaded\n");
+		setrenderneeded = 0;
+		return;
+	}
+#endif
+
 	// setting the same renderer twice WILL crash your game, so let's not, please
 	if (rendermode == setrenderneeded)
 		setrenderneeded = 0;
diff --git a/src/sdl/i_video.c b/src/sdl/i_video.c
index bacb4f771..1dbaf06bd 100644
--- a/src/sdl/i_video.c
+++ b/src/sdl/i_video.c
@@ -1440,7 +1440,7 @@ static SDL_bool Impl_CreateContext(void)
 {
 	// Renderer-specific stuff
 #ifdef HWRENDER
-	if (rendermode == render_opengl)
+	if ((rendermode == render_opengl) && (hwrenderloaded != -1))
 	{
 		if (!sdlglcontext)
 			sdlglcontext = SDL_GL_CreateContext(window);
@@ -1478,7 +1478,6 @@ static void VID_CheckGLLoaded(rendermode_t oldrender)
 {
 	if (hwrenderloaded == -1) // Well, it didn't work the first time anyway.
 	{
-		CONS_Alert(CONS_ERROR, "OpenGL never loaded\n");
 		rendermode = oldrender;
 		if (chosenrendermode == render_opengl) // fallback to software
 			rendermode = render_soft;
@@ -1587,7 +1586,8 @@ static SDL_bool Impl_CreateWindow(SDL_bool fullscreen)
 		flags |= SDL_WINDOW_BORDERLESS;
 
 #ifdef HWRENDER
-	flags |= SDL_WINDOW_OPENGL;
+	if (hwrenderloaded != -1)
+		flags |= SDL_WINDOW_OPENGL;
 #endif
 
 	// Create a window
@@ -1721,7 +1721,10 @@ void I_StartupGraphics(void)
 	//SDL_EnableKeyRepeat(SDL_DEFAULT_REPEAT_DELAY>>1,SDL_DEFAULT_REPEAT_INTERVAL<<2);
 	VID_Command_ModeList_f();
 #ifdef HWRENDER
-	I_StartupHardwareGraphics();
+	if (M_CheckParm("-nogl"))
+		hwrenderloaded = -1; // Don't call SDL_GL_LoadLibrary
+	else
+		I_StartupHardwareGraphics();
 #endif
 
 	// Fury: we do window initialization after GL setup to allow