src/dedicated/i_video.c

@@ -152,3 +152,8 @@ boolean I_UseNativeKeyboard(void)
 {
 	return false;
 }
+
+void I_SetBorderlessWindow(void) 
+{
+
+}

src/i_video.h

@@ -145,6 +145,8 @@ boolean I_UseNativeKeyboard(void);
 
 boolean I_CheckNativeRes(void);
 
+void I_SetBorderlessWindow(void);
+
 #ifdef USE_FBO_OGL
 
 void RefreshOGLSDLSurface(void);

src/screen.c

@@ -66,7 +66,9 @@ static void Highreshudscale_OnChange(void)
 
 static void SCR_ChangeFullscreen (void);
 
-consvar_t cv_fullscreen = {"fullscreen", "Yes", CV_SAVE|CV_CALL, CV_YesNo, SCR_ChangeFullscreen, 0, NULL, NULL, 0, 0, NULL};
+static CV_PossibleValue_t fullscreen_cons_t[] = {{0, "No"}, {1, "Yes"}, {2, "Borderless Window"}, {0, NULL}};
+
+consvar_t cv_fullscreen = {"fullscreen", "Yes", CV_SAVE|CV_CALL, fullscreen_cons_t, SCR_ChangeFullscreen, 0, NULL, NULL, 0, 0, NULL};
 
 static CV_PossibleValue_t accuratefps_cons_t[] = {{0, "Inaccurate"}, {1, "Accurate"}, {0, NULL}};
 consvar_t cv_accuratefps = {"fpssampling", "1", CV_SAVE, accuratefps_cons_t, NULL, 0, NULL, NULL, 0, 0, NULL};
@@ -325,6 +327,8 @@ void SCR_SetDefaultMode(void)
 void SCR_ChangeFullscreen(void)
 {
 #ifdef DIRECTFULLSCREEN
+	I_SetBorderlessWindow(); // Running this here so we can have borderless window at startup
+
 	// allow_fullscreen is set by VID_PrepareModeList
 	// it is used to prevent switching to fullscreen during startup
 	if (!allow_fullscreen)

src/sdl/i_video.c

@@ -150,7 +150,7 @@ UINT8 graphics_started = 0; // Is used in console.c and screen.c
 // To disable fullscreen at startup; is set in VID_PrepareModeList
 boolean allow_fullscreen = false;
 static SDL_bool disable_fullscreen = SDL_FALSE;
-#define USE_FULLSCREEN (disable_fullscreen||!allow_fullscreen)?0:cv_fullscreen.value
+#define USE_FULLSCREEN (disable_fullscreen||!allow_fullscreen)? 0: (cv_fullscreen.value == 1)
 static SDL_bool disable_mouse = SDL_FALSE;
 #define USE_MOUSEINPUT (!disable_mouse && cv_usemouse.value && havefocus)
 #define MOUSE_MENU false //(!disable_mouse && cv_usemouse.value && menuactive && !USE_FULLSCREEN)
@@ -1353,6 +1353,7 @@ static void SDLSetMode(INT32 width, INT32 height, SDL_bool fullscreen)
 		{
 			wasfullscreen = SDL_TRUE;
 			SDL_SetWindowFullscreen(window, SDL_WINDOW_FULLSCREEN_DESKTOP);
+			I_SetBorderlessWindow();
 		}
 		else // windowed mode
 		{
@@ -2157,4 +2158,10 @@ static void Impl_SetVsync(void)
 #endif
 }
 
+void I_SetBorderlessWindow(void)
+{
+	SDL_bool borderless = (cv_fullscreen.value == 2) ? SDL_FALSE : SDL_TRUE;
+	SDL_SetWindowBordered(window, borderless);
+}
+
 #endif