veloren/common/src/comp/states/mod.rs

// Module declarations
mod basic_attack;
mod basic_block;
mod charge_attack;
mod climb;
mod fall;
mod glide;
mod idle;
mod jump;
mod roll;
mod run;
mod sit;
mod stand;
mod swim;
mod wield;

// Reexports
pub use basic_attack::*;
pub use basic_block::*;
pub use charge_attack::*;
pub use climb::*;
pub use fall::*;
pub use glide::*;
pub use idle::*;
pub use jump::*;
pub use roll::*;
pub use run::*;
pub use sit::*;
pub use stand::*;
pub use swim::*;
pub use wield::*;

// TODO: Attach these to racial components and/or ecs resources
pub const HUMANOID_ACCEL: f32 = 50.0;
pub const HUMANOID_SPEED: f32 = 120.0;
pub const HUMANOID_AIR_ACCEL: f32 = 10.0;
pub const HUMANOID_AIR_SPEED: f32 = 100.0;
pub const HUMANOID_WATER_ACCEL: f32 = 70.0;
pub const HUMANOID_WATER_SPEED: f32 = 120.0;
pub const HUMANOID_CLIMB_ACCEL: f32 = 5.0;
pub const ROLL_SPEED: f32 = 17.0;
pub const CHARGE_SPEED: f32 = 20.0;
pub const GLIDE_ACCEL: f32 = 15.0;
pub const GLIDE_SPEED: f32 = 45.0;
pub const BLOCK_ACCEL: f32 = 30.0;
pub const BLOCK_SPEED: f32 = 75.0;
pub const TEMP_EQUIP_DELAY: u64 = 100;
// Gravity is 9.81 * 4, so this makes gravity equal to .15
pub const GLIDE_ANTIGRAV: f32 = crate::sys::phys::GRAVITY * 0.96;
pub const CLIMB_SPEED: f32 = 5.0;
pub const MOVEMENT_THRESHOLD_VEL: f32 = 3.0;

use super::{
    ActionState, ActionState::*, AttackKind::*, BlockKind::*, DodgeKind::*, EcsStateData,
    MoveState, MoveState::*, StateUpdate,
};

/// #### A trait for implementing state `handle()`ing logic.
///  _Mimics the typical OOP style state machine pattern, but remains performant and consistent
///  with ECS data-behavior-separation constraint since trait fn's are syntactic sugar for
///  static fn's that accept their implementor's object type as its first parameter. This allows
///  for several benefits over implementing each state's behavior within the `CharacterState` update `System`
///  itself:_
///  
///  1. Less cognitive overhead: State's handling logic is next to the its data, and component (inside the state's .rs file).
///  2. Separation of concerns (between states): all logic within a state's `handle()` is relevant only to that state.
///     States can be added/editted without concerns of affecting other state's logic.
///  3. Clearly defined API and pattern: All states accept the same `EcsStateData` struct, which can be added to as necessary,
///     without the need for updating every state's implementation. All states return the same `StateUpdate` component.
///     `CharacterState` update `System` passes `EcsStateData` to `ActionState`/`MoveState` `handle()` which matches the character's
///     current state to its `handle()` fn, hiding the implementation details, since the System is only concerned with
///     how the update flow occurs and is in charge of updating the ECS components.
pub trait StateHandle {
    fn handle(&self, ecs_data: &EcsStateData) -> StateUpdate;
}

// Public interface that passes EcsStateData to `StateHandle`s `handle()` fn
impl StateHandle for ActionState {
    /// Passes handle to variant or subvariant handlers
    fn handle(&self, ecs_data: &EcsStateData) -> StateUpdate {
        match self {
            Attack(kind) => match kind {
                BasicAttack(state) => state.handle(ecs_data),
                Charge(state) => state.handle(ecs_data),
            },
            Block(kind) => match kind {
                BasicBlock(state) => state.handle(ecs_data),
            },
            Dodge(kind) => match kind {
                Roll(state) => state.handle(ecs_data),
            },
            Wield(state) => state.handle(ecs_data),
            Idle(state) => state.handle(ecs_data),
            // All states should be explicitly handled
            // Do not use default match: _ => {},
        }
    }
}

/// Public interface that passes EcsStateData to `StateHandle`s `handle()` fn
impl StateHandle for MoveState {
    /// Passes handle to variant handlers
    fn handle(&self, ecs_data: &EcsStateData) -> StateUpdate {
        match self {
            Stand(state) => state.handle(&ecs_data),
            Run(state) => state.handle(&ecs_data),
            Jump(state) => state.handle(&ecs_data),
            Climb(state) => state.handle(&ecs_data),
            Glide(state) => state.handle(&ecs_data),
            Swim(state) => state.handle(&ecs_data),
            Fall(state) => state.handle(&ecs_data),
            Sit(state) => state.handle(&ecs_data),
            // All states should be explicitly handled
            // Do not use default match: _ => {},
        }
    }
}