Implement up smash, dacus and further improve input system. (#88)

Reviewed-on: #88
Co-authored-by: Álex Román Núñez <eirexe@eirteam.moe>

src/input/buffer.rs

@@ -9,6 +9,8 @@ use crate::fighter::FighterFacingDirection;
 use crate::fighter::attack::AttackKind;
 use crate::game_settings::GameSettings;
 use crate::input::{DigitalAction, FighterInputFrame};
+use crate::math::int::FGi32;
+use crate::math::vec::FGVec2;
 use crate::netcode::GGRSCfg;
 use crate::player::Player;
 
@@ -64,6 +66,34 @@ pub enum FighterAttackCommandType {
     TiltAttackRight,
 }
 
+#[derive(Clone, Copy, Debug, Hash, PartialEq, Eq)]
+pub enum FlickDirection {
+    Up,
+    Down,
+    Left,
+    Right,
+}
+
+impl FlickDirection {
+    const fn smash_move_command(self) -> FighterCommands {
+        match self {
+            Self::Up => FighterCommands::SmashMoveUp,
+            Self::Down => FighterCommands::SmashMoveDown,
+            Self::Left => FighterCommands::SmashMoveLeft,
+            Self::Right => FighterCommands::SmashMoveRight,
+        }
+    }
+
+    const fn smash_attack_command(self) -> FighterAttackCommandType {
+        match self {
+            Self::Up => FighterAttackCommandType::SmashAttackUp,
+            Self::Down => FighterAttackCommandType::SmashAttackDown,
+            Self::Left => FighterAttackCommandType::SmashAttackLeft,
+            Self::Right => FighterAttackCommandType::SmashAttackRight,
+        }
+    }
+}
+
 impl FighterAttackCommandType {
     pub fn to_attack_kind_grounded(&self) -> AttackKind {
         match self {
@@ -193,6 +223,149 @@ impl ButtonHistory {
     }
 }
 
+#[derive(Clone, Copy, Debug, Hash)]
+struct FlickAxisState {
+    age: u8,
+    eligible: bool,
+    consumed: bool,
+    command_emitted: bool,
+}
+
+impl Default for FlickAxisState {
+    fn default() -> Self {
+        Self {
+            age: u8::MAX,
+            eligible: false,
+            consumed: false,
+            command_emitted: false,
+        }
+    }
+}
+
+impl FlickAxisState {
+    fn update(
+        &mut self,
+        current: FGi32,
+        previous: FGi32,
+        reset_threshold: FGi32,
+        axis_threshold: FGi32,
+        frame_threshold: u8,
+    ) {
+        if current.abs() < reset_threshold {
+            *self = Self::default();
+            return;
+        }
+
+        if previous.abs() < reset_threshold || previous.signum() != current.signum() {
+            self.age = 1;
+            self.consumed = false;
+            self.command_emitted = false;
+        } else {
+            self.age = self.age.saturating_add(1);
+        }
+
+        self.eligible =
+            !self.consumed && current.abs() >= axis_threshold && self.age <= frame_threshold;
+    }
+}
+
+#[derive(Clone, Copy, Debug, Default, Hash)]
+struct StickFlickState {
+    x: FlickAxisState,
+    y: FlickAxisState,
+}
+
+impl StickFlickState {
+    fn update(
+        &mut self,
+        current: FGVec2,
+        previous: FGVec2,
+        reset_threshold: FGi32,
+        axis_threshold: FGi32,
+        frame_threshold: u8,
+    ) {
+        self.x.update(
+            current.x,
+            previous.x,
+            reset_threshold,
+            axis_threshold,
+            frame_threshold,
+        );
+        self.y.update(
+            current.y,
+            previous.y,
+            reset_threshold,
+            axis_threshold,
+            frame_threshold,
+        );
+    }
+
+    fn peek(&self, value: FGVec2) -> Option<FlickDirection> {
+        self.resolve(value, self.x.eligible, self.y.eligible)
+    }
+
+    /// Returns each axis that has not produced a passive command during this
+    /// gesture. This does not consume the flick, so an attack can still use
+    /// the remainder of its smash-input window.
+    fn next_commands(&mut self, value: FGVec2) -> [Option<FlickDirection>; 2] {
+        let use_x = self.x.eligible && !self.x.command_emitted;
+        let use_y = self.y.eligible && !self.y.command_emitted;
+
+        if use_x {
+            self.x.command_emitted = true;
+        }
+        if use_y {
+            self.y.command_emitted = true;
+        }
+
+        [
+            use_x.then_some(if value.x.is_positive() {
+                FlickDirection::Right
+            } else {
+                FlickDirection::Left
+            }),
+            use_y.then_some(if value.y.is_positive() {
+                FlickDirection::Up
+            } else {
+                FlickDirection::Down
+            }),
+        ]
+    }
+
+    fn consume(&mut self, value: FGVec2) -> Option<FlickDirection> {
+        let direction = self.peek(value)?;
+        // Simultaneous eligible axes are one diagonal gesture. Consuming only
+        // the selected axis would expose the other axis on the next frame.
+        if self.x.eligible {
+            self.x.consumed = true;
+            self.x.eligible = false;
+        }
+        if self.y.eligible {
+            self.y.consumed = true;
+            self.y.eligible = false;
+        }
+        Some(direction)
+    }
+
+    fn resolve(&self, value: FGVec2, use_x: bool, use_y: bool) -> Option<FlickDirection> {
+        if use_x {
+            Some(if value.x.is_positive() {
+                FlickDirection::Right
+            } else {
+                FlickDirection::Left
+            })
+        } else if use_y {
+            Some(if value.y.is_positive() {
+                FlickDirection::Up
+            } else {
+                FlickDirection::Down
+            })
+        } else {
+            None
+        }
+    }
+}
+
 /// Per-fighter input state. Every field is deterministic rollback state.
 #[derive(Component, Clone, Copy, Hash)]
 #[require(Rollback)]
@@ -203,8 +376,8 @@ pub struct FighterInput {
     button_history: [ButtonHistory; 3],
     prev_frame: FighterInputFrame,
     current_frame: FighterInputFrame,
-    frames_in_x_flick_deadzone: u8,
-    frames_in_y_flick_deadzone: u8,
+    movement_flick: StickFlickState,
+    directional_attack_flick: StickFlickState,
     attack_command: FighterAttackCommandType,
 }
 
@@ -217,8 +390,8 @@ impl Default for FighterInput {
             button_history: [ButtonHistory::default(); 3],
             prev_frame: FighterInputFrame::default(),
             current_frame: FighterInputFrame::default(),
-            frames_in_x_flick_deadzone: 0xFE,
-            frames_in_y_flick_deadzone: 0xFE,
+            movement_flick: StickFlickState::default(),
+            directional_attack_flick: StickFlickState::default(),
             attack_command: FighterAttackCommandType::Neutral,
         }
     }
@@ -368,8 +541,26 @@ impl FighterInput {
         self.current_frame.bindings_for(action).count()
     }
 
-    pub fn get_frames_in_smash_move_deadzone(&self) -> u8 {
-        self.frames_in_x_flick_deadzone
+    pub fn peek_movement_flick(&self) -> Option<FlickDirection> {
+        self.movement_flick.peek(self.current_frame.movement)
+    }
+
+    pub fn peek_movement_flick_dbg(&self) -> u8 {
+        self.movement_flick.y.age
+    }
+
+    pub fn consume_movement_flick(&mut self) -> Option<FlickDirection> {
+        self.movement_flick.consume(self.current_frame.movement)
+    }
+
+    pub fn peek_directional_attack_flick(&self) -> Option<FlickDirection> {
+        self.directional_attack_flick
+            .peek(self.current_frame.directional_attack)
+    }
+
+    pub fn consume_directional_attack_flick(&mut self) -> Option<FlickDirection> {
+        self.directional_attack_flick
+            .consume(self.current_frame.directional_attack)
     }
     pub fn set_attack_command_type(&mut self, command: FighterAttackCommandType) {
         self.attack_command = command;
@@ -441,31 +632,30 @@ pub fn postprocess_input(
             );
         }
 
-        let x_abs = input.current_frame.movement.x.abs();
-        let y_abs = input.current_frame.movement.y.abs();
+        let movement = input.current_frame.movement;
+        let previous_movement = input.prev_frame.movement;
+        let directional_attack = input.current_frame.directional_attack;
+        let previous_directional_attack = input.prev_frame.directional_attack;
+        let x_abs = movement.x.abs();
+        let y_abs = movement.y.abs();
         let reset_deadzone = game_settings.input_common.smash_input_reset_axis_threshold;
         let axis_threshold = game_settings.input_common.smash_input_axis_threshold;
         let frame_threshold = game_settings.input_common.smash_input_frame_threshold;
 
-        if x_abs < reset_deadzone {
-            input.frames_in_x_flick_deadzone = 0xFE;
-        } else if input.prev_frame.movement.x.abs() < reset_deadzone
-            || input.prev_frame.movement.x.signum() != input.current_frame.movement.x.signum()
-        {
-            input.frames_in_x_flick_deadzone = 1;
-        } else {
-            input.frames_in_x_flick_deadzone = input.frames_in_x_flick_deadzone.saturating_add(1);
-        }
-
-        if y_abs < reset_deadzone {
-            input.frames_in_y_flick_deadzone = 0xFE;
-        } else if input.prev_frame.movement.y.abs() < reset_deadzone
-            || input.prev_frame.movement.y.signum() != input.current_frame.movement.y.signum()
-        {
-            input.frames_in_y_flick_deadzone = 1;
-        } else {
-            input.frames_in_y_flick_deadzone = input.frames_in_y_flick_deadzone.saturating_add(1);
-        }
+        input.movement_flick.update(
+            movement,
+            previous_movement,
+            reset_deadzone,
+            axis_threshold,
+            frame_threshold,
+        );
+        input.directional_attack_flick.update(
+            directional_attack,
+            previous_directional_attack,
+            reset_deadzone,
+            axis_threshold,
+            frame_threshold,
+        );
 
         let tap = game_settings.input_common.input_buffer_size;
         let jump_pressed = input.is_pressed(DigitalAction::Jump);
@@ -485,62 +675,40 @@ pub fn postprocess_input(
             input.set_lifetime(FighterCommands::GuardHold, tap);
         }
 
-        let mut y_flick_detected =
-            y_abs >= axis_threshold && input.frames_in_y_flick_deadzone <= frame_threshold;
-        let mut x_flick_detected =
-            x_abs >= axis_threshold && input.frames_in_x_flick_deadzone <= frame_threshold;
-        if y_flick_detected {
-            input.clear_command(FighterCommands::SmashMoveUp);
-            input.clear_command(FighterCommands::SmashMoveDown);
-            input.frames_in_y_flick_deadzone = 0xFF;
-            let command = if input.current_frame.movement.y > 0.0 {
-                FighterCommands::SmashMoveUp
-            } else {
-                FighterCommands::SmashMoveDown
-            };
+        for flick in input
+            .movement_flick
+            .next_commands(movement)
+            .into_iter()
+            .flatten()
+        {
+            let command = flick.smash_move_command();
+            match flick {
+                FlickDirection::Up | FlickDirection::Down => {
+                    input.clear_command(FighterCommands::SmashMoveUp);
+                    input.clear_command(FighterCommands::SmashMoveDown);
+                }
+                FlickDirection::Left | FlickDirection::Right => {
+                    input.clear_command(FighterCommands::SmashMoveLeft);
+                    input.clear_command(FighterCommands::SmashMoveRight);
+                }
+            }
             input.set_lifetime(command, tap);
-        }
-        if x_flick_detected {
-            input.clear_command(FighterCommands::SmashMoveLeft);
-            input.clear_command(FighterCommands::SmashMoveRight);
-            input.frames_in_x_flick_deadzone = 0xFF;
-            let command = if input.current_frame.movement.x > 0.0 {
-                FighterCommands::SmashMoveRight
-            } else {
-                FighterCommands::SmashMoveLeft
-            };
-            input.set_lifetime(command, tap);
-        }
-        if x_flick_detected && y_flick_detected {
-            x_flick_detected = x_abs > y_abs;
-            y_flick_detected = !x_flick_detected;
-        }
-
-        if y_flick_detected && input.current_frame.movement.y > 0.0 {
-            input.set_lifetime(FighterCommands::TapJump, tap);
+            if flick == FlickDirection::Up {
+                input.set_lifetime(FighterCommands::TapJump, tap);
+            }
         }
 
         if attack_pressed {
-            let attack_type = if y_flick_detected {
-                if input.current_frame.movement.y > 0.0 {
-                    FighterAttackCommandType::SmashAttackUp
-                } else {
-                    FighterAttackCommandType::SmashAttackDown
-                }
-            } else if x_flick_detected {
-                if input.current_frame.movement.x > 0.0 {
-                    FighterAttackCommandType::SmashAttackRight
-                } else {
-                    FighterAttackCommandType::SmashAttackLeft
-                }
+            let attack_type = if let Some(flick) = input.consume_movement_flick() {
+                flick.smash_attack_command()
             } else if x_abs > y_abs {
-                if input.current_frame.movement.x.is_positive() {
+                if movement.x.is_positive() {
                     FighterAttackCommandType::TiltAttackRight
                 } else {
                     FighterAttackCommandType::TiltAttackLeft
                 }
             } else if y_abs > x_abs {
-                if input.current_frame.movement.y.is_positive() {
+                if movement.y.is_positive() {
                     FighterAttackCommandType::TiltAttackUp
                 } else {
                     FighterAttackCommandType::TiltAttackDown
@@ -548,10 +716,17 @@ pub fn postprocess_input(
             } else {
                 FighterAttackCommandType::Neutral
             };
+
+            dbg!(input.movement_flick.y, attack_type);
             input.set_lifetime(FighterCommands::Attack, tap);
             input.set_attack_command_type(attack_type);
         }
 
+        if let Some(flick) = input.consume_directional_attack_flick() {
+            input.set_lifetime(FighterCommands::Attack, tap);
+            input.set_attack_command_type(flick.smash_attack_command());
+        }
+
         for command in FighterCommands::iter() {
             input.update_hold(command);
         }
@@ -563,6 +738,20 @@ mod tests {
     use super::*;
     use crate::input::ActionBindingMask;
 
+    const RESET_THRESHOLD: FGi32 = FGi32::lit("0.2");
+    const AXIS_THRESHOLD: FGi32 = FGi32::lit("0.8");
+    const FRAME_THRESHOLD: u8 = 3;
+
+    fn update_flick(state: &mut StickFlickState, current: FGVec2, previous: FGVec2) {
+        state.update(
+            current,
+            previous,
+            RESET_THRESHOLD,
+            AXIS_THRESHOLD,
+            FRAME_THRESHOLD,
+        );
+    }
+
     fn advance_command(input: &mut FighterInput, command: FighterCommands) {
         input.reduce_command_lifetime(command);
         input.update_hold(command);
@@ -583,6 +772,94 @@ mod tests {
         assert!(second_binding_pressed(current, previous));
     }
 
+    #[test]
+    fn flick_remains_available_for_the_configured_window() {
+        let mut flick = StickFlickState::default();
+        let right = FGVec2::lit("1", "0");
+
+        update_flick(&mut flick, right, FGVec2::ZERO);
+        assert_eq!(flick.peek(right), Some(FlickDirection::Right));
+
+        for _ in 2..=FRAME_THRESHOLD {
+            update_flick(&mut flick, right, right);
+            assert_eq!(flick.peek(right), Some(FlickDirection::Right));
+        }
+
+        update_flick(&mut flick, right, right);
+        assert_eq!(flick.peek(right), None);
+    }
+
+    #[test]
+    fn passive_command_does_not_consume_flick() {
+        let mut flick = StickFlickState::default();
+        let right = FGVec2::lit("1", "0");
+
+        update_flick(&mut flick, right, FGVec2::ZERO);
+        assert_eq!(
+            flick.next_commands(right),
+            [Some(FlickDirection::Right), None]
+        );
+        assert_eq!(flick.next_commands(right), [None, None]);
+        assert_eq!(flick.peek(right), Some(FlickDirection::Right));
+
+        update_flick(&mut flick, right, right);
+        assert_eq!(flick.consume(right), Some(FlickDirection::Right));
+        assert_eq!(flick.peek(right), None);
+    }
+
+    #[test]
+    fn consumed_flick_rearms_after_returning_below_reset_threshold() {
+        let mut flick = StickFlickState::default();
+        let right = FGVec2::lit("1", "0");
+
+        update_flick(&mut flick, right, FGVec2::ZERO);
+        assert_eq!(flick.consume(right), Some(FlickDirection::Right));
+        update_flick(&mut flick, right, right);
+        assert_eq!(flick.peek(right), None);
+
+        update_flick(&mut flick, FGVec2::ZERO, right);
+        update_flick(&mut flick, right, FGVec2::ZERO);
+        assert_eq!(flick.peek(right), Some(FlickDirection::Right));
+    }
+
+    #[test]
+    fn flick_can_reach_activation_threshold_after_entering_reset_deadzone() {
+        let mut flick = StickFlickState::default();
+        let partial = FGVec2::lit("0.4", "0");
+        let right = FGVec2::lit("1", "0");
+
+        update_flick(&mut flick, partial, FGVec2::ZERO);
+        assert_eq!(flick.peek(partial), None);
+        update_flick(&mut flick, right, partial);
+        assert_eq!(flick.peek(right), Some(FlickDirection::Right));
+    }
+
+    #[test]
+    fn diagonal_flick_prioritizes_horizontal_and_consumes_the_gesture() {
+        let mut flick = StickFlickState::default();
+        let diagonal = FGVec2::lit("0.9", "1");
+
+        update_flick(&mut flick, diagonal, FGVec2::ZERO);
+        assert_eq!(
+            flick.next_commands(diagonal),
+            [Some(FlickDirection::Right), Some(FlickDirection::Up)]
+        );
+        assert_eq!(flick.consume(diagonal), Some(FlickDirection::Right));
+        assert_eq!(flick.peek(diagonal), None);
+    }
+
+    #[test]
+    fn direction_reversal_starts_a_new_flick() {
+        let mut flick = StickFlickState::default();
+        let right = FGVec2::lit("1", "0");
+        let left = FGVec2::lit("-1", "0");
+
+        update_flick(&mut flick, right, FGVec2::ZERO);
+        assert_eq!(flick.consume(right), Some(FlickDirection::Right));
+        update_flick(&mut flick, left, right);
+        assert_eq!(flick.peek(left), Some(FlickDirection::Left));
+    }
+
     #[test]
     fn command_can_be_consumed_without_erasing_raw_input() {
         let mut input = FighterInput::default();