LibWeb: Implement the Gamepad API with SDL3

Author: https://github.com/Lubrsi
Commit: 74e0483ea5
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/5902
Reviewed-by: https://github.com/gmta
Reviewed-by: https://github.com/trflynn89

Libraries/LibWeb/Page/EventHandler.cpp

@@ -20,6 +20,7 @@
 #include <LibWeb/HTML/HTMLImageElement.h>
 #include <LibWeb/HTML/HTMLMediaElement.h>
 #include <LibWeb/HTML/HTMLVideoElement.h>
+#include <LibWeb/HTML/Navigator.h>
 #include <LibWeb/Layout/Label.h>
 #include <LibWeb/Layout/Viewport.h>
 #include <LibWeb/Page/DragAndDropEventHandler.h>
@@ -37,6 +38,8 @@
 #include <LibWeb/UIEvents/PointerEvent.h>
 #include <LibWeb/UIEvents/WheelEvent.h>
 
+#include <SDL3/SDL_events.h>
+
 namespace Web {
 
 #define FIRE(expression)                                                          \
@@ -1459,6 +1462,56 @@ EventResult EventHandler::handle_paste(String const& text)
     return EventResult::Handled;
 }
 
+void EventHandler::handle_gamepad_connected(SDL_JoystickID sdl_joystick_id)
+{
+    auto active_document = m_navigable->active_document();
+    if (active_document)
+        active_document->window()->navigator()->handle_gamepad_connected(sdl_joystick_id);
+
+    for (auto child_navigable : m_navigable->child_navigables())
+        child_navigable->event_handler().handle_gamepad_connected(sdl_joystick_id);
+}
+
+void EventHandler::handle_gamepad_updated(SDL_JoystickID sdl_joystick_id)
+{
+    auto active_document = m_navigable->active_document();
+    if (active_document)
+        active_document->window()->navigator()->handle_gamepad_updated({}, sdl_joystick_id);
+
+    for (auto child_navigable : m_navigable->child_navigables())
+        child_navigable->event_handler().handle_gamepad_updated(sdl_joystick_id);
+}
+
+void EventHandler::handle_gamepad_disconnected(SDL_JoystickID sdl_joystick_id)
+{
+    auto active_document = m_navigable->active_document();
+    if (active_document)
+        active_document->window()->navigator()->handle_gamepad_disconnected({}, sdl_joystick_id);
+
+    for (auto child_navigable : m_navigable->child_navigables())
+        child_navigable->event_handler().handle_gamepad_disconnected(sdl_joystick_id);
+}
+
+void EventHandler::handle_sdl_input_events()
+{
+    SDL_Event event;
+    while (SDL_PollEvent(&event)) {
+        switch (event.type) {
+        case SDL_EVENT_GAMEPAD_ADDED:
+            handle_gamepad_connected(event.gdevice.which);
+            break;
+        case SDL_EVENT_GAMEPAD_UPDATE_COMPLETE:
+            handle_gamepad_updated(event.gdevice.which);
+            break;
+        case SDL_EVENT_GAMEPAD_REMOVED:
+            handle_gamepad_disconnected(event.gdevice.which);
+            break;
+        default:
+            break;
+        }
+    }
+}
+
 void EventHandler::set_mouse_event_tracking_paintable(GC::Ptr<Painting::Paintable> paintable)
 {
     m_mouse_event_tracking_paintable = paintable;

Libraries/LibWeb/Page/EventHandler.h

@@ -20,6 +20,8 @@
 #include <LibWeb/PixelUnits.h>
 #include <LibWeb/UIEvents/KeyCode.h>
 
+#include <SDL3/SDL_joystick.h>
+
 namespace Web {
 
 class WEB_API EventHandler {
@@ -43,6 +45,8 @@ public:
 
     EventResult handle_paste(String const& text);
 
+    void handle_sdl_input_events();
+
     void visit_edges(JS::Cell::Visitor& visitor) const;
 
     Unicode::Segmenter& word_segmenter();
@@ -68,6 +72,10 @@ private:
 
     bool should_ignore_device_input_event() const;
 
+    void handle_gamepad_connected(SDL_JoystickID);
+    void handle_gamepad_updated(SDL_JoystickID);
+    void handle_gamepad_disconnected(SDL_JoystickID);
+
     GC::Ref<HTML::Navigable> m_navigable;
 
     bool m_in_mouse_selection { false };

Libraries/LibWeb/Page/Page.cpp

@@ -244,6 +244,11 @@ EventResult Page::handle_keyup(UIEvents::KeyCode key, unsigned modifiers, u32 co
     return focused_navigable().event_handler().handle_keyup(key, modifiers, code_point, repeat);
 }
 
+void Page::handle_sdl_input_events()
+{
+    top_level_traversable()->event_handler().handle_sdl_input_events();
+}
+
 void Page::set_top_level_traversable(GC::Ref<HTML::TraversableNavigable> navigable)
 {
     VERIFY(!m_top_level_traversable); // Replacement is not allowed!

Libraries/LibWeb/Page/Page.h

@@ -102,6 +102,8 @@ public:
     EventResult handle_keydown(UIEvents::KeyCode, unsigned modifiers, u32 code_point, bool repeat);
     EventResult handle_keyup(UIEvents::KeyCode, unsigned modifiers, u32 code_point, bool repeat);
 
+    void handle_sdl_input_events();
+
     Gfx::Palette palette() const;
     CSSPixelRect web_exposed_screen_area() const;
     CSS::PreferredColorScheme preferred_color_scheme() const;