From 7013490e596dc06ec32f92358ca28cddf772c8a3 Mon Sep 17 00:00:00 2001
From: eri <eri@inventati.org>
Date: Sat, 13 Jul 2024 20:10:50 +0200
Subject: [PATCH] feat: basic touch input

---
 Cargo.toml       |  4 +++-
 examples/jump.rs |  2 +-
 src/input.rs     | 55 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 59 insertions(+), 2 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 9b39bed..6276592 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -25,8 +25,9 @@ release = [ # Only in release (build with --release --no-default-features --feat
   "bevy_embedded_assets",
   "common",
   "tts",
+  "touch",
 ]
-common = ["input", "menu", "ui", "persist"]
+common = ["input", "menu", "persist", "ui"]
 
 3d_camera = []
 input = ["leafwing-input-manager"]
@@ -35,6 +36,7 @@ navigation = ["bevy-alt-ui-navigation-lite"]
 persist = ["bevy-persistent"]
 pixel_perfect = []
 resizable = []
+touch = ["input"]
 trace = ["release", "bevy/trace_tracy"]
 ui = ["sickle_ui"]
 
diff --git a/examples/jump.rs b/examples/jump.rs
index 0a7585c..0640087 100644
--- a/examples/jump.rs
+++ b/examples/jump.rs
@@ -203,7 +203,7 @@ fn update_player(
     };
 
     // Move
-    let axis = input.axis_pair(&Action::Move);
+    let axis = input.clamped_axis_pair(&Action::Move);
     let dir = axis.unwrap_or_default().x();
     if dir.abs() > 0. {
         player.velocity.x = dir * MOVE_VEL;
diff --git a/src/input.rs b/src/input.rs
index 3ca9321..af89446 100644
--- a/src/input.rs
+++ b/src/input.rs
@@ -23,6 +23,15 @@ impl Plugin for InputPlugin {
             Update,
             handle_input.run_if(in_state(crate::GameState::Play)),
         );
+
+        #[cfg(feature = "touch")]
+        app.add_systems(
+            PreUpdate,
+            touch_system
+                .chain()
+                .after(bevy::input::InputSystem)
+                .before(leafwing_input_manager::plugin::InputManagerSystem::Update),
+        );
     }
 }
 
@@ -52,11 +61,16 @@ fn init(mut cmd: Commands) {
     input_map
         .insert(Action::Jump, KeyCode::Space)
         .insert(Action::Jump, GamepadButtonType::South)
+        .insert(Action::Jump, MouseButton::Left)
         .insert(Action::Move, KeyboardVirtualDPad::WASD)
         .insert(Action::Move, GamepadStick::LEFT)
         .insert(Action::Pause, KeyCode::Escape)
         .insert(Action::Pause, GamepadButtonType::Start);
 
+    // If touch input is enabled, make the touch movement map to the move action
+    #[cfg(feature = "touch")]
+    input_map.insert(Action::Move, MouseMove::default());
+
     cmd.spawn(InputManagerBundle::with_map(input_map));
 }
 
@@ -74,3 +88,44 @@ fn handle_input(
         next_state.set(crate::GameState::Menu)
     }
 }
+
+/// Touch inputs are converted to equivalent mouse values to make them
+/// compatible with leafwing
+#[cfg(feature = "touch")]
+fn touch_system(
+    window: Query<Entity, With<bevy::window::PrimaryWindow>>,
+    touches: Res<Touches>,
+    mut mouse_button_writer: EventWriter<bevy::input::mouse::MouseButtonInput>,
+    mut cursor_moved_writer: EventWriter<CursorMoved>,
+) {
+    use bevy::input::{mouse::MouseButtonInput, ButtonState};
+
+    let Ok(window) = window.get_single() else { return };
+
+    for _ in touches.iter_just_pressed() {
+        mouse_button_writer.send(MouseButtonInput {
+            button: MouseButton::Left,
+            state: ButtonState::Pressed,
+            window,
+        });
+    }
+
+    for _ in touches.iter_just_released() {
+        mouse_button_writer.send(MouseButtonInput {
+            button: MouseButton::Left,
+            state: ButtonState::Released,
+            window,
+        });
+    }
+
+    // Doesn't support multitouch
+    let Some(touch) = touches.iter().next() else {
+        return;
+    };
+
+    cursor_moved_writer.send(CursorMoved {
+        position: touch.position(),
+        delta: Some(touch.delta()),
+        window,
+    });
+}