use SDL's desktop fullscreen flag for simpler fullscreen behavior, and use Emscripten's fullscreen functionality for web builds; add a flag for disabling fullscreen through the configuration

src/Configuration.cpp

@@ -51,7 +51,8 @@ void Configuration::set_defaults()
         {"default font path", "BPmono.ttf"},
         {"default font size", 16},
         {"use play button", false},
-        {"fullscreen", false}
+        {"fullscreen", false},
+        {"fullscreen enabled", true}
     };
     config["audio"] = {
         {"default-sfx-root", "resource/sfx"},

src/Display.cpp

@@ -186,38 +186,39 @@ void sb::Display::respond(SDL_Event& event)
 
 void sb::Display::toggle_fullscreen() const
 {
-    if (SDL_GetWindowFlags(const_cast<SDL_Window*>(window())) & SDL_WINDOW_FULLSCREEN)
+    if (configuration()("display", "fullscreen enabled"))
     {
-        sb::Log::log("exit fullscreen requested");
+#if !defined(__EMSCRIPTEN__)
-        SDL_SetWindowFullscreen(const_cast<SDL_Window*>(window()), 0);
+        if (SDL_GetWindowFlags(const_cast<SDL_Window*>(window())) & SDL_WINDOW_FULLSCREEN_DESKTOP)
-    }
-    else
-    {
-        /* Get the index of the display currently displaying the game window */
-        int display_index;
-        if ((display_index = SDL_GetWindowDisplayIndex(const_cast<SDL_Window*>(window()))) < 0)
         {
-            display_index = 0;
+            sb::Log::log("Fullscreen requested");
-            sb::Log::sdl_error("Error getting current display index of window, defaulting to index 0.");
+            SDL_SetWindowFullscreen(const_cast<SDL_Window*>(window()), 0);
-        }
-
-        /* Get the display mode (including the resolution) of the display currently displaying the window */
-        SDL_DisplayMode mode;
-        if (SDL_GetDesktopDisplayMode(display_index, &mode) != 0)
-        {
-            sb::Log::sdl_error("Error getting display mode");
         }
         else
         {
-            /* Set the window's fullscreen display mode to the same as the desktop to use the same resolution */
+            sb::Log::log("Exit fullscreen requested");
-            sb::Log::log("Setting window's fullscreen display mode to current desktop display mode");
+            SDL_SetWindowFullscreen(const_cast<SDL_Window*>(window()), SDL_WINDOW_FULLSCREEN_DESKTOP);
-            if (SDL_SetWindowDisplayMode(const_cast<SDL_Window*>(window()), &mode) != 0)
-            {
-                sb::Log::sdl_error("Error setting window's fullscreen display mode");
-            }
         }
+#else
+        EmscriptenFullscreenChangeEvent status;
+        emscripten_get_fullscreen_status(&status);
+        if (!status.isFullscreen)
+        {
+            sb::Log::log("Fullscreen requested");
 
-        sb::Log::log("fullscreen requested");
+            /* Set a string to refer to Module.canvas. See https://emscripten.org/docs/api_reference/html5.h.html#registration-functions */
-        SDL_SetWindowFullscreen(const_cast<SDL_Window*>(window()), SDL_WINDOW_FULLSCREEN);
+            EM_ASM(specialHTMLTargets["!canvas"] = Module.canvas;);
+            emscripten_request_fullscreen("!canvas", true);
+        }
+        else
+        {
+            sb::Log::log("Exit fullscreen requested");
+            emscripten_exit_fullscreen();
+        }
+#endif
+    }
+    else
+    {
+        sb::Log::log("Fullscreen requested, but it is currently disabled by the configuration.", sb::Log::WARN);
     }
 }

src/Display.hpp

@@ -11,11 +11,19 @@
 #pragma once
 
 #include <sstream>
+
 #include "glm/vec2.hpp"
+
 #include "SDL.h"
 #include "SDL_image.h"
+
 #include "sdl2-gfx/SDL2_gfxPrimitives.h"
 #include "sdl2-gfx/SDL2_rotozoom.h"
+
+#if defined(__EMSCRIPTEN__)
+#include "emscripten/html5.h"
+#endif
+
 #include "Node.hpp"
 #include "Box.hpp"
 #include "Log.hpp"
@@ -52,13 +60,14 @@ namespace sb
         void respond(SDL_Event& event);
 
         /*!
-         * Query SDL window flags to determine if fullscreen is on or off and use SDL's fullscreen function to toggle the fullscreen
+         * Set window to fullscreen if it is not currently displayed fullscreen, otherwise exit fullscreen.
-         * state to the opposite state.
          *
-         * Before calling SDL's fullscreen function, this function queries the display index to find out which display (for example,
+         * In builds other than Emscripten, this uses the SDL_WINDOW_FULLSCREEN_DESKTOP flag to create a fullscreen window. SDL creates
-         * which monitor in a dual-screen system) is displaying the window. It then sets the window's fullscreen display mode to the
+         * the fullscreen window without changing video modes by resizing the window to the size of desktop and removing borders.
-         * current desktop display mode of that display. This ensures that the fullscreen will succeed smoothly, without a resolution
+         * 
-         * change, but it also requires that the game is adaptable to dynamic window sizing.
+         * Emscripten builds use `emscripten_request_fullscreen()` instead, which handles fullscreen from web browsers more smoothly.
+         *
+         * If "display" > "fullscreen enabled" is false in the configuration, this function does nothing.
          */
         void toggle_fullscreen() const;