Fix run direction not being taken into account when accelerating (Fixes #11)

Fixes #22

Extracts shared grounded collision/friction and airborne movement/landing policies while preserving state-specific behavior. Running fighters now pass `can_walk_off = true` so they can run off platform edges. Includes grounded and airborne hitstun call sites.

Reviewed-on: #36
Co-authored-by: Álex Román Núñez <eirexe@eirteam.moe>

src/fighter/state/air.rs

@@ -1,3 +1,6 @@
+use crate::fighter::state::ground::GroundedStateCommon;
+use crate::fighter::state::land::{LandingState, LandingType};
+use crate::fighter::state::{CollisionContext, FighterState};
 use crate::fighter::*;
 
 pub fn integrate_gravity(velocity: &mut FighterVelocity, attributes: &FighterAttributes) {
@@ -53,6 +56,27 @@ pub fn apply_air_motion(
     translation.0 += velocity.0;
 }
 
+pub fn update_standard_motion(ctx: &mut crate::fighter::state::UpdateContext) {
+    integrate_gravity(ctx.velocity, ctx.fighter_attributes);
+    apply_air_drift(ctx.velocity, ctx.fighter_attributes, ctx.input);
+    apply_air_motion(ctx.velocity, ctx.translation, ctx.prev_translation);
+}
+
+pub fn collision_interrupt(
+    ctx: &mut CollisionContext,
+    landing_type: LandingType,
+) -> Option<FighterState> {
+    let res = ctx.air_collide_with_stage()?;
+    ctx.translation.0 = res.hit_position - ctx.ecb.get_bottom_point();
+    let grounded_common = GroundedStateCommon {
+        current_line_id: res.line_id,
+    };
+    Some(FighterState::Land(LandingState::create(
+        grounded_common,
+        landing_type,
+    )))
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

src/fighter/state/air_dodge.rs

@@ -3,10 +3,7 @@ use crate::{
         animation::AnimKind,
         state::{
             CollisionContext, EnterContext, FighterState, FighterStateImpl, InterruptContext,
-            UpdateContext, air,
-            fall::FallState,
-            ground::GroundedStateCommon,
-            land::{LandingState, LandingType},
+            UpdateContext, air, fall::FallState, land::LandingType,
         },
     },
     input,
@@ -43,19 +40,7 @@ impl FighterStateImpl for AirDodgeState {
         &mut self,
         state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
-        if let Some(res) = state_context.air_collide_with_stage() {
-            // Adjust translation
-            state_context.translation.0 = res.hit_position - state_context.ecb.get_bottom_point();
-            let grounded_common = GroundedStateCommon {
-                current_line_id: res.line_id,
-            };
-            Some(FighterState::Land(LandingState {
-                grounded_common,
-                landing_type: LandingType::Special,
-            }))
-        } else {
-            None
-        }
+        air::collision_interrupt(state_context, LandingType::Special)
     }
 
     fn on_enter(&mut self, state_context: &mut EnterContext) {

src/fighter/state/dash.rs

@@ -5,8 +5,7 @@ use super::{
 use crate::fighter::FighterFacingDirection;
 use crate::fighter::animation::AnimKind;
 use crate::fighter::state::FighterState;
-use crate::fighter::state::fall::FallState;
-use crate::fighter::state::ground::{GroundedMotionResult, GroundedStateCommon};
+use crate::fighter::state::ground::GroundedStateCommon;
 use crate::input::FighterCommands::{SmashMoveLeft, SmashMoveRight};
 
 #[derive(Debug, Clone, Hash)]
@@ -107,13 +106,7 @@ impl FighterStateImpl for DashState {
         &mut self,
         state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
-        if let GroundedMotionResult::InAir =
-            ground::collide_with_stage_grounded(state_context, &mut self.ground_common, true)
-        {
-            Some(FighterState::Fall(FallState))
-        } else {
-            None
-        }
+        ground::collision_interrupt(state_context, &mut self.ground_common, true)
     }
 }
 

src/fighter/state/fall.rs

@@ -1,7 +1,5 @@
 use super::{CollisionContext, EnterContext, FighterStateImpl, InterruptContext, UpdateContext};
 use crate::fighter::animation::AnimKind;
-use crate::fighter::state::ground::GroundedStateCommon;
-use crate::fighter::state::land::{LandingState, LandingType};
 use crate::fighter::state::{FighterState, air, jump};
 
 #[derive(Debug, Clone, Copy, Hash)]
@@ -18,36 +16,17 @@ impl FighterStateImpl for FallState {
     }
 
     fn update(&mut self, state_context: &mut UpdateContext) {
-        air::integrate_gravity(state_context.velocity, state_context.fighter_attributes);
-        air::apply_air_drift(
-            state_context.velocity,
-            state_context.fighter_attributes,
-            state_context.input,
-        );
-        air::apply_air_motion(
-            state_context.velocity,
-            state_context.translation,
-            state_context.prev_translation,
-        );
+        air::update_standard_motion(state_context);
     }
 
     fn check_collision_interrupt(
         &mut self,
         state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
-        if let Some(res) = state_context.air_collide_with_stage() {
-            // Adjust translation
-            state_context.translation.0 = res.hit_position - state_context.ecb.get_bottom_point();
-            let grounded_common = GroundedStateCommon {
-                current_line_id: res.line_id,
-            };
-            Some(FighterState::Land(LandingState::create(
-                grounded_common,
-                LandingType::Normal,
-            )))
-        } else {
-            None
-        }
+        air::collision_interrupt(
+            state_context,
+            crate::fighter::state::land::LandingType::Normal,
+        )
     }
 }
 

src/fighter/state/ground.rs

@@ -3,7 +3,7 @@
 //! bit-for-bit deterministic for rollback.
 
 use crate::fighter::state::{
-    CollisionContext, FighterState, InterruptContext, dash, ground_attack, turn, wait, walk,
+    CollisionContext, FighterState, InterruptContext, dash, fall, ground_attack, turn, wait, walk,
 };
 use crate::fighter::{
     FighterAttributes, FighterPreviousTranslation, FighterTranslation, FighterVelocity,
@@ -163,6 +163,22 @@ pub fn apply_grounded_motion(
     translation.0 += FGVec2::new(velocity.0.x, FGi32::ZERO);
 }
 
+pub fn update_friction_motion(ctx: &mut crate::fighter::state::UpdateContext) {
+    let friction = if ctx.velocity.x.abs() > ctx.fighter_attributes.max_walk_vel {
+        ctx.fighter_attributes.ground_friction
+            * ctx
+                .game_settings
+                .fighter_common
+                .ground_friction_over_walk_speed_multiplier
+    } else {
+        ctx.fighter_attributes.ground_friction
+    };
+
+    let ground_velocity = ctx.velocity.x;
+    ctx.velocity.x += apply_grounded_friction(friction, ground_velocity);
+    apply_grounded_motion(ctx.velocity, ctx.translation, ctx.prev_translation);
+}
+
 pub fn collide_with_stage_grounded(
     state_context: &mut CollisionContext,
     ground_common: &mut GroundedStateCommon,
@@ -210,6 +226,17 @@ pub fn collide_with_stage_grounded(
     }
 }
 
+pub fn collision_interrupt(
+    ctx: &mut CollisionContext,
+    common: &mut GroundedStateCommon,
+    can_walk_off: bool,
+) -> Option<FighterState> {
+    match collide_with_stage_grounded(ctx, common, can_walk_off) {
+        GroundedMotionResult::InGround => None,
+        GroundedMotionResult::InAir => Some(FighterState::Fall(fall::FallState)),
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

src/fighter/state/hitstun.rs

@@ -6,8 +6,8 @@ use crate::{
             CollisionContext, EnterContext, ExitContext, FighterState, FighterStateImpl,
             InterruptContext, UpdateContext, air,
             fall::FallState,
-            ground::{GroundedMotionResult, GroundedStateCommon, collide_with_stage_grounded},
-            land::{LandingState, LandingType},
+            ground::{GroundedStateCommon, collision_interrupt},
+            land::LandingType,
             wait::WaitState,
         },
     },
@@ -88,29 +88,10 @@ impl FighterStateImpl for HitstunState {
     ) -> Option<FighterState> {
         match &mut self.hitstop_kind {
             HitstopStateKind::Grounded(grounded_state_common) => {
-                if let GroundedMotionResult::InAir =
-                    collide_with_stage_grounded(state_context, grounded_state_common, true)
-                {
-                    Some(FighterState::Fall(FallState {}))
-                } else {
-                    None
-                }
+                collision_interrupt(state_context, grounded_state_common, true)
             }
             HitstopStateKind::Airborne => {
-                if let Some(res) = state_context.air_collide_with_stage() {
-                    // Adjust translation
-                    state_context.translation.0 =
-                        res.hit_position - state_context.ecb.get_bottom_point();
-                    let grounded_common = GroundedStateCommon {
-                        current_line_id: res.line_id,
-                    };
-                    Some(FighterState::Land(LandingState::create(
-                        grounded_common,
-                        LandingType::Normal,
-                    )))
-                } else {
-                    None
-                }
+                air::collision_interrupt(state_context, LandingType::Normal)
             }
         }
     }

src/fighter/state/jump.rs

@@ -7,9 +7,7 @@ use crate::{
             CollisionContext, EnterContext, FighterState, FighterStateImpl, InterruptContext,
             UpdateContext, air,
             air_dodge::{self, AirDodgeState},
-            fall::FallState,
-            ground::{self, GroundedMotionResult, GroundedStateCommon},
-            land::{LandingState, LandingType},
+            ground::{self, GroundedStateCommon},
         },
     },
     input::FighterCommands,
@@ -84,40 +82,14 @@ impl FighterStateImpl for JumpSquatState {
 
     fn update(&mut self, state_context: &mut UpdateContext) {
         self.duration_counter += 1;
-
-        let friction =
-            if state_context.velocity.x.abs() > state_context.fighter_attributes.max_walk_vel {
-                state_context.fighter_attributes.ground_friction
-                    * state_context
-                        .game_settings
-                        .fighter_common
-                        .ground_friction_over_walk_speed_multiplier
-            } else {
-                state_context.fighter_attributes.ground_friction
-            };
-
-        let ground_velocity = state_context.velocity.x;
-
-        state_context.velocity.x += ground::apply_grounded_friction(friction, ground_velocity);
-
-        ground::apply_grounded_motion(
-            state_context.velocity,
-            state_context.translation,
-            state_context.prev_translation,
-        );
+        ground::update_friction_motion(state_context);
     }
 
     fn check_collision_interrupt(
         &mut self,
         state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
-        if let GroundedMotionResult::InAir =
-            ground::collide_with_stage_grounded(state_context, &mut self.grounded_common, false)
-        {
-            Some(FighterState::Fall(FallState))
-        } else {
-            None
-        }
+        ground::collision_interrupt(state_context, &mut self.grounded_common, false)
     }
 
     fn on_enter(&mut self, state_context: &mut EnterContext) {
@@ -139,17 +111,7 @@ impl FighterStateImpl for JumpState {
     }
 
     fn update(&mut self, state_context: &mut UpdateContext) {
-        air::integrate_gravity(state_context.velocity, state_context.fighter_attributes);
-        air::apply_air_drift(
-            state_context.velocity,
-            state_context.fighter_attributes,
-            state_context.input,
-        );
-        air::apply_air_motion(
-            state_context.velocity,
-            state_context.translation,
-            state_context.prev_translation,
-        );
+        air::update_standard_motion(state_context);
     }
 
     fn on_enter(&mut self, state_context: &mut EnterContext) {
@@ -207,19 +169,10 @@ impl FighterStateImpl for JumpState {
         &mut self,
         state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
-        if let Some(res) = state_context.air_collide_with_stage() {
-            // Adjust translation
-            state_context.translation.0 = res.hit_position - state_context.ecb.get_bottom_point();
-            let grounded_common = GroundedStateCommon {
-                current_line_id: res.line_id,
-            };
-            Some(FighterState::Land(LandingState::create(
-                grounded_common,
-                LandingType::Normal,
-            )))
-        } else {
-            None
-        }
+        air::collision_interrupt(
+            state_context,
+            crate::fighter::state::land::LandingType::Normal,
+        )
     }
 }
 

src/fighter/state/land.rs

@@ -3,11 +3,7 @@ use crate::fighter::{
     state::{
         CollisionContext, EnterContext, FighterState, FighterStateImpl, InterruptContext,
         UpdateContext, dash,
-        fall::FallState,
-        ground::{
-            self, GroundedMotionResult, GroundedStateCommon,
-            grounded_movement_standstill_common_interrupts,
-        },
+        ground::{self, GroundedStateCommon, grounded_movement_standstill_common_interrupts},
         walk,
     },
 };
@@ -53,39 +49,14 @@ impl FighterStateImpl for LandingState {
     }
 
     fn update(&mut self, state_context: &mut UpdateContext) {
-        let friction =
-            if state_context.velocity.x.abs() > state_context.fighter_attributes.max_walk_vel {
-                state_context.fighter_attributes.ground_friction
-                    * state_context
-                        .game_settings
-                        .fighter_common
-                        .ground_friction_over_walk_speed_multiplier
-            } else {
-                state_context.fighter_attributes.ground_friction
-            };
-
-        let ground_velocity = state_context.velocity.x;
-
-        state_context.velocity.x += ground::apply_grounded_friction(friction, ground_velocity);
-
-        ground::apply_grounded_motion(
-            state_context.velocity,
-            state_context.translation,
-            state_context.prev_translation,
-        );
+        ground::update_friction_motion(state_context);
     }
 
     fn check_collision_interrupt(
         &mut self,
         state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
-        if let GroundedMotionResult::InAir =
-            ground::collide_with_stage_grounded(state_context, &mut self.grounded_common, true)
-        {
-            Some(FighterState::Fall(FallState))
-        } else {
-            None
-        }
+        ground::collision_interrupt(state_context, &mut self.grounded_common, true)
     }
 
     fn on_enter(&mut self, state_context: &mut EnterContext) {

src/fighter/state/mod.rs

@@ -150,6 +150,7 @@ pub struct UpdateContext<'a> {
     pub fighter_attributes: &'a FighterAttributes,
     pub attack_scripts: &'a Assets<FighterAttackScript>,
     pub attack_script_assets: &'a FighterAttackScriptAssets,
+    pub facing_direction: &'a FighterFacingDirection,
 }
 
 impl UpdateContext<'_> {
@@ -290,6 +291,7 @@ impl<'w, 's> FighterFrameQueryItem<'w, 's> {
             fighter_attributes: attributes,
             attack_scripts,
             attack_script_assets,
+            facing_direction: &self.facing_direction
         }
     }
 

src/fighter/state/run.rs

@@ -6,9 +6,7 @@ use super::{
 };
 use crate::fighter::animation::AnimKind;
 use crate::fighter::state::FighterState;
-use crate::fighter::state::fall::FallState;
-use crate::fighter::state::ground::{GroundedMotionResult, GroundedStateCommon};
-use crate::math::int::FGi32;
+use crate::fighter::state::ground::GroundedStateCommon;
 
 #[derive(Component, Debug, Clone, Hash)]
 pub struct RunState {
@@ -43,7 +41,7 @@ impl FighterStateImpl for RunState {
         let last_frame = state_context.input.get_last_frame();
         let (accel, target_vel) = state_context
             .fighter_attributes
-            .get_accel_and_target_dashrun(&last_frame, FGi32::ONE);
+            .get_accel_and_target_dashrun(&last_frame, state_context.facing_direction.to_sign());
         let accel = ground::compute_ground_accel(
             accel,
             target_vel,
@@ -64,13 +62,7 @@ impl FighterStateImpl for RunState {
         &mut self,
         state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
-        if let GroundedMotionResult::InAir =
-            ground::collide_with_stage_grounded(state_context, &mut self.grounded_common, false)
-        {
-            Some(FighterState::Fall(FallState))
-        } else {
-            None
-        }
+        ground::collision_interrupt(state_context, &mut self.grounded_common, true)
     }
 }
 

src/fighter/state/turn.rs

@@ -1,7 +1,6 @@
 use super::{CollisionContext, EnterContext, FighterStateImpl, InterruptContext, UpdateContext};
 use crate::fighter::animation::AnimKind;
-use crate::fighter::state::fall::FallState;
-use crate::fighter::state::ground::{self, GroundedMotionResult, GroundedStateCommon};
+use crate::fighter::state::ground::{self, GroundedStateCommon};
 use crate::fighter::state::{FighterState, dash, jump, wait, walk};
 use crate::input::FighterCommands;
 
@@ -48,39 +47,14 @@ impl FighterStateImpl for TurnState {
     }
 
     fn update(&mut self, state_context: &mut UpdateContext) {
-        let friction =
-            if state_context.velocity.x.abs() > state_context.fighter_attributes.max_walk_vel {
-                state_context.fighter_attributes.ground_friction
-                    * state_context
-                        .game_settings
-                        .fighter_common
-                        .ground_friction_over_walk_speed_multiplier
-            } else {
-                state_context.fighter_attributes.ground_friction
-            };
-
-        let ground_velocity = state_context.velocity.x;
-
-        state_context.velocity.x += ground::apply_grounded_friction(friction, ground_velocity);
-
-        ground::apply_grounded_motion(
-            state_context.velocity,
-            state_context.translation,
-            state_context.prev_translation,
-        );
+        ground::update_friction_motion(state_context);
     }
 
     fn check_collision_interrupt(
         &mut self,
         state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
-        if let GroundedMotionResult::InAir =
-            ground::collide_with_stage_grounded(state_context, &mut self.grounded_common, false)
-        {
-            Some(FighterState::Fall(FallState))
-        } else {
-            None
-        }
+        ground::collision_interrupt(state_context, &mut self.grounded_common, false)
     }
 }
 

src/fighter/state/wait.rs

@@ -3,8 +3,7 @@ use super::{
 };
 use crate::fighter::animation::AnimKind;
 use crate::fighter::state::FighterState;
-use crate::fighter::state::fall::FallState;
-use crate::fighter::state::ground::{GroundedMotionResult, GroundedStateCommon};
+use crate::fighter::state::ground::GroundedStateCommon;
 
 #[derive(Debug, Clone, Hash)]
 pub struct WaitState {
@@ -38,39 +37,14 @@ impl FighterStateImpl for WaitState {
     }
 
     fn update(&mut self, state_context: &mut UpdateContext) {
-        let friction =
-            if state_context.velocity.x.abs() > state_context.fighter_attributes.max_walk_vel {
-                state_context.fighter_attributes.ground_friction
-                    * state_context
-                        .game_settings
-                        .fighter_common
-                        .ground_friction_over_walk_speed_multiplier
-            } else {
-                state_context.fighter_attributes.ground_friction
-            };
-
-        let ground_velocity = state_context.velocity.x;
-
-        state_context.velocity.x += ground::apply_grounded_friction(friction, ground_velocity);
-
-        ground::apply_grounded_motion(
-            state_context.velocity,
-            state_context.translation,
-            state_context.prev_translation,
-        );
+        ground::update_friction_motion(state_context);
     }
 
     fn check_collision_interrupt(
         &mut self,
         state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
-        if let GroundedMotionResult::InAir =
-            ground::collide_with_stage_grounded(state_context, &mut self.grounded_common, false)
-        {
-            Some(FighterState::Fall(FallState))
-        } else {
-            None
-        }
+        ground::collision_interrupt(state_context, &mut self.grounded_common, false)
     }
 }
 

src/fighter/state/walk.rs

@@ -4,8 +4,7 @@ use super::{
 };
 use crate::fighter::animation::AnimKind;
 use crate::fighter::state::FighterState;
-use crate::fighter::state::fall::FallState;
-use crate::fighter::state::ground::{GroundedMotionResult, GroundedStateCommon};
+use crate::fighter::state::ground::GroundedStateCommon;
 
 #[derive(Debug, Clone, Hash)]
 pub struct WalkState {
@@ -55,13 +54,7 @@ impl FighterStateImpl for WalkState {
         &mut self,
         state_context: &mut CollisionContext,
     ) -> Option<FighterState> {
-        if let GroundedMotionResult::InAir =
-            ground::collide_with_stage_grounded(state_context, &mut self.grounded_common, false)
-        {
-            Some(FighterState::Fall(FallState))
-        } else {
-            None
-        }
+        ground::collision_interrupt(state_context, &mut self.grounded_common, false)
     }
 }