lyra-engine/examples/testbed/src/main.rs

use lyra_engine::{math::{self, Vec3}, ecs::{World, components::{transform::TransformComponent, camera::CameraComponent, model::ModelComponent, DeltaTime}, EventQueue, SimpleSystem, Component, Criteria, CriteriaSchedule, BatchedSystem}, math::Transform, input::{KeyCode, InputButtons, MouseMotion}, game::Game, plugin::Plugin, render::window::{CursorGrabMode, WindowOptions}, change_tracker::Ct};
use lyra_engine::assets::{ResourceManager, Model};

mod free_fly_camera;
use free_fly_camera::{FreeFlyCameraPlugin, FreeFlyCamera};

struct FixedTimestep {
    max_tps: u32,
    fixed_time: f32,
    accumulator: f32,
}

impl FixedTimestep {
    pub fn new(max_tps: u32) -> Self {
        Self {
            max_tps,
            fixed_time: Self::calc_fixed_time(max_tps),
            accumulator: 0.0,
        }
    }

    fn calc_fixed_time(max_tps: u32) -> f32 {
        1.0 / max_tps as f32
    }

    fn set_tps(&mut self, tps: u32) {
        self.max_tps = tps;
        self.fixed_time = Self::calc_fixed_time(tps);
    }

    fn tps(&self) -> u32 {
        self.max_tps
    }

    fn fixed_time(&self) -> f32 {
        self.fixed_time
    }
}

impl Criteria for FixedTimestep {
    fn can_run(&mut self, world: &mut edict::World, check_count: u32) -> CriteriaSchedule {
        if check_count == 0 {
            let delta_time = world.get_resource::<DeltaTime>().unwrap();
            self.accumulator += **delta_time;
        }

        if self.accumulator >= self.fixed_time {
            self.accumulator -= self.fixed_time;
            return CriteriaSchedule::YesAndLoop;
        }

        CriteriaSchedule::No
    }
}

#[derive(Clone)]
struct TpsAccumulator(f32);

#[async_std::main]
async fn main() {
    let setup_sys = |world: &mut World| -> anyhow::Result<()> {
        {
            let mut window_options = world.get_resource_mut::<Ct<WindowOptions>>().unwrap();
            window_options.cursor_grab = CursorGrabMode::Confined;
            window_options.cursor_visible = false;
        }

        let mut resman = world.get_resource_mut::<ResourceManager>().unwrap();
        //let diffuse_texture = resman.request::<Texture>("assets/happy-tree.png").unwrap();
        let antique_camera_model = resman.request::<Model>("assets/AntiqueCamera.glb").unwrap();
        //let cube_model = resman.request::<Model>("assets/texture-sep/texture-sep.gltf").unwrap();
        drop(resman);

        /* world.spawn((
            ModelComponent(cube_model.clone()),
            TransformComponent::from(Transform::from_xyz(3.0, 0.5, -2.2)),
        )); */

        world.spawn((
            ModelComponent(antique_camera_model),
            TransformComponent::from(Transform::from_xyz(0.0, -5.0, -10.0)),
        ));

        let mut camera = CameraComponent::new_3d();
        camera.transform.translation += math::Vec3::new(0.0, 0.0, 7.5);
        //camera.transform.rotate_y(Angle::Degrees(-25.0));
        //camera.transform.rotate_z(math::Angle::Degrees(-90.0));
        world.spawn(( camera, FreeFlyCamera::default() ));

        Ok(())
    };

    let fps_system = |world: &mut World| -> anyhow::Result<()> {
        let mut counter = world.get_resource_mut::<fps_counter::FPSCounter>().unwrap();

        let fps = counter.tick();

        println!("FPS: {fps}");

        Ok(())
    };
    let fps_plugin = move |game: &mut Game| {
        let world = game.world();
        world.insert_resource(fps_counter::FPSCounter::new());
    };

    let spin_system = |world: &mut World| -> anyhow::Result<()> {
        const SPEED: f32 = 5.0;
        let delta_time = **world.get_resource::<DeltaTime>().unwrap();

        for transform in world.query_mut::<(&mut TransformComponent,)>().iter_mut() {
            let t = &mut transform.transform;
            t.rotate_y(math::Angle::Degrees(SPEED * delta_time));
        }

        Ok(())
    };

    let jiggle_plugin = move |game: &mut Game| {
        game.world().insert_resource(TpsAccumulator(0.0));
        
        let mut sys = BatchedSystem::new();
        sys.with_criteria(FixedTimestep::new(30));
        sys.with_system(spin_system);
        sys.with_system(fps_system);

        game.with_system("fixed", sys, &[]);
        fps_plugin(game);
    };
    
    Game::initialize().await
        .with_plugin(lyra_engine::DefaultPlugins)
        .with_startup_system(setup_sys)
        //.with_plugin(fps_plugin)
        .with_plugin(jiggle_plugin)
        .with_plugin(FreeFlyCameraPlugin)
        .run().await;
}