veloren/common/src/states/glide.rs

use crate::{
    comp::{CharacterState, StateUpdate},
    sys::character_behavior::JoinData,
};
use std::collections::VecDeque;
use vek::{Vec2, Vec3};

// Gravity is 9.81 * 4, so this makes gravity equal to .15
const GLIDE_ANTIGRAV: f32 = crate::sys::phys::GRAVITY * 0.96;
const GLIDE_ACCEL: f32 = 15.0;
const GLIDE_SPEED: f32 = 45.0;

pub fn behavior(data: &JoinData) -> StateUpdate {
    let mut update = StateUpdate {
        pos: *data.pos,
        vel: *data.vel,
        ori: *data.ori,
        energy: *data.energy,
        character: *data.character,
        local_events: VecDeque::new(),
        server_events: VecDeque::new(),
    };

    // If glide button isn't held or player is on ground, end glide
    if !data.inputs.glide.is_pressed() || data.physics.on_ground {
        update.character = CharacterState::Idle {};
    }

    // If there is a wall in front of character go to climb
    if let Some(_) = data.physics.on_wall {
        update.character = CharacterState::Climb {};
    }

    // Move player according to movement direction vector
    update.vel.0 += Vec2::broadcast(data.dt.0)
        * data.inputs.move_dir
        * if data.vel.0.magnitude_squared() < GLIDE_SPEED.powf(2.0) {
            GLIDE_ACCEL
        } else {
            0.0
        };

    // Determine orientation vector from movement direction vector
    let ori_dir = Vec2::from(update.vel.0);
    if ori_dir.magnitude_squared() > 0.0001
        && (update.ori.0.normalized() - Vec3::from(ori_dir).normalized()).magnitude_squared()
            > 0.001
    {
        update.ori.0 = vek::ops::Slerp::slerp(update.ori.0, ori_dir.into(), 2.0 * data.dt.0);
    }

    // Apply Glide antigrav lift
    if Vec2::<f32>::from(update.vel.0).magnitude_squared() < GLIDE_SPEED.powf(2.0)
        && update.vel.0.z < 0.0
    {
        let lift = GLIDE_ANTIGRAV + update.vel.0.z.abs().powf(2.0) * 0.15;
        update.vel.0.z += data.dt.0
            * lift
            * (Vec2::<f32>::from(update.vel.0).magnitude() * 0.075)
                .min(1.0)
                .max(0.2);
    }

    // Otherwise keep gliding
    update
}