Initial work on rollback and refactor

src/fighter/state/walk.rs

@@ -0,0 +1,43 @@
+use bevy::prelude::*;
+
+use super::{FighterState, FighterStateContext, FighterStateTransition, dash, ground, wait};
+use crate::fighter::{FighterAttributes, FighterVelocity};
+use crate::game_settings::GameSettings;
+use crate::input::FighterInput;
+
+#[derive(Component, Debug, Clone, Copy)]
+pub struct WalkState;
+
+impl FighterState for WalkState {
+    fn check_interrupt(
+        &self,
+        state_context: &FighterStateContext,
+    ) -> Option<FighterStateTransition> {
+        wait::check_input(state_context).or_else(|| dash::check_input(state_context))
+    }
+}
+
+pub fn check_input(state_context: &FighterStateContext) -> Option<FighterStateTransition> {
+    let input_frame = state_context.input.get_last_frame();
+
+    if input_frame.movement.x.abs() >= state_context.game_settings.input_common.stick_deadzone {
+        return Some(FighterStateTransition::Walk);
+    }
+
+    None
+}
+
+pub fn walk_update(
+    fighters: Query<(&mut FighterVelocity, &FighterAttributes, &FighterInput), With<WalkState>>,
+    game_settings: Res<GameSettings>,
+) {
+    for (mut velocity, attributes, input) in fighters {
+        let last_frame = input.get_last_frame();
+        let (accel, target_vel) = attributes.get_accel_and_target_walk(&last_frame);
+
+        let accel =
+            ground::compute_ground_accel(accel, target_vel, velocity.x, attributes, &game_settings);
+
+        velocity.x += accel;
+    }
+}