Added documentation to WindowMode to better document what 'use_size' … (#3216)

This pull request aims to solve the issue of a lack of documentation in the enum WindowMode

# Objective

- Fixes #3136

## Solution

- Added a few lines of documentation that should document what the enum does better

crates/bevy_window/src/window.rs

@@ -183,15 +183,17 @@ pub enum WindowCommand {
 }
 
 /// Defines the way a window is displayed
-/// The use_size option that is used in the Fullscreen variant
-/// defines whether a videomode is chosen that best fits the width and height
-/// in the Window structure, or if these are ignored.
-/// E.g. when use_size is set to false the best video mode possible is chosen.
 #[derive(Debug, Clone, Copy, PartialEq)]
 pub enum WindowMode {
+    /// Creates a window that uses the given size
     Windowed,
+    /// Creates a borderless window that uses the full size of the screen
     BorderlessFullscreen,
-    Fullscreen { use_size: bool },
+    /// Creates a fullscreen window that will render at desktop resolution. The app will use the closest supported size
+    /// from the given size and scale it to fit the screen.
+    SizedFullscreen,
+    /// Creates a fullscreen window that uses the maximum supported size
+    Fullscreen,
 }
 
 impl Window {

crates/bevy_winit/src/lib.rs

@@ -59,16 +59,18 @@ fn change_window(world: &mut World) {
                         bevy_window::WindowMode::BorderlessFullscreen => {
                             window.set_fullscreen(Some(winit::window::Fullscreen::Borderless(None)))
                         }
-                        bevy_window::WindowMode::Fullscreen { use_size } => window.set_fullscreen(
+                        bevy_window::WindowMode::Fullscreen => {
-                            Some(winit::window::Fullscreen::Exclusive(match use_size {
+                            window.set_fullscreen(Some(winit::window::Fullscreen::Exclusive(
-                                true => get_fitting_videomode(
+                                get_best_videomode(&window.current_monitor().unwrap()),
-                                    &window.current_monitor().unwrap(),
+                            )))
-                                    width,
+                        }
-                                    height,
+                        bevy_window::WindowMode::SizedFullscreen => window.set_fullscreen(Some(
-                                ),
+                            winit::window::Fullscreen::Exclusive(get_fitting_videomode(
-                                false => get_best_videomode(&window.current_monitor().unwrap()),
+                                &window.current_monitor().unwrap(),
-                            })),
+                                width,
-                        ),
+                                height,
+                            )),
+                        )),
                         bevy_window::WindowMode::Windowed => window.set_fullscreen(None),
                     }
                 }

crates/bevy_winit/src/winit_windows.rs

@@ -31,15 +31,17 @@ impl WinitWindows {
             WindowMode::BorderlessFullscreen => winit_window_builder.with_fullscreen(Some(
                 winit::window::Fullscreen::Borderless(event_loop.primary_monitor()),
             )),
-            WindowMode::Fullscreen { use_size } => winit_window_builder.with_fullscreen(Some(
+            WindowMode::Fullscreen => {
-                winit::window::Fullscreen::Exclusive(match use_size {
+                winit_window_builder.with_fullscreen(Some(winit::window::Fullscreen::Exclusive(
-                    true => get_fitting_videomode(
+                    get_best_videomode(&event_loop.primary_monitor().unwrap()),
-                        &event_loop.primary_monitor().unwrap(),
+                )))
-                        window_descriptor.width as u32,
+            }
-                        window_descriptor.height as u32,
+            WindowMode::SizedFullscreen => winit_window_builder.with_fullscreen(Some(
-                    ),
+                winit::window::Fullscreen::Exclusive(get_fitting_videomode(
-                    false => get_best_videomode(&event_loop.primary_monitor().unwrap()),
+                    &event_loop.primary_monitor().unwrap(),
-                }),
+                    window_descriptor.width as u32,
+                    window_descriptor.height as u32,
+                )),
             )),
             _ => {
                 let WindowDescriptor {
@@ -180,6 +182,7 @@ impl WinitWindows {
         self.winit_to_window_id.get(&id).cloned()
     }
 }
+
 pub fn get_fitting_videomode(
     monitor: &winit::monitor::MonitorHandle,
     width: u32,