Galactica/src/objects/ship.rs

use cgmath::{Deg, EuclideanSpace, InnerSpace, Matrix2, Rad, Vector2};
use content::{FactionHandle, TextureHandle};
use nalgebra::vector;
use rand::Rng;
use rapier2d::{
	dynamics::{RigidBody, RigidBodyBuilder},
	geometry::ColliderBuilder,
	pipeline::ActiveEvents,
};

use super::ProjectileBuilder;
use crate::{
	content,
	game::outfits,
	physics::{util, ShipHandle},
	render::Sprite,
};

pub struct ShipTickResult {
	pub projectiles: Vec<ProjectileBuilder>,
}

pub struct ShipControls {
	pub left: bool,
	pub right: bool,
	pub thrust: bool,
	pub guns: bool,
}

impl ShipControls {
	pub fn new() -> Self {
		ShipControls {
			left: false,
			right: false,
			thrust: false,
			guns: false,
		}
	}
}

pub struct Ship {
	pub physics_handle: ShipHandle,
	pub faction: FactionHandle,
	pub hull: f32,
	pub controls: ShipControls,

	outfits: outfits::ShipOutfits,
	sprite_texture: TextureHandle,
	size: f32,
}

impl Ship {
	pub fn new(
		c: &content::Ship,
		outfits: Vec<outfits::ShipOutfit>,
		physics_handle: ShipHandle,
		faction: FactionHandle,
	) -> Self {
		let mut o = outfits::ShipOutfits::new(c);
		for x in outfits.into_iter() {
			o.add(x)
		}

		Ship {
			physics_handle,
			outfits: o,
			sprite_texture: c.sprite_texture,
			size: c.size,
			hull: c.hull,
			controls: ShipControls::new(),
			faction,
		}
	}

	pub fn fire_guns(&mut self, r: &RigidBody) -> Vec<ProjectileBuilder> {
		let mut rng = rand::thread_rng();
		let mut out = Vec::new();

		for (g, p) in self.outfits.iter_guns_points() {
			if g.cooldown > 0.0 {
				continue;
			}

			g.cooldown = g.kind.rate + rng.gen_range(-g.kind.rate_rng..=g.kind.rate_rng);

			let ship_pos = util::rigidbody_position(r);
			let ship_rot = util::rigidbody_rotation(r);
			let ship_vel = util::rigidbody_velocity(r);
			let ship_ang = ship_rot.angle(Vector2 { x: 0.0, y: 1.0 });

			let pos = ship_pos + (Matrix2::from_angle(-ship_ang) * p.pos.to_vec());

			let spread: Rad<f32> =
				Deg(rng.gen_range(-(g.kind.spread.0 / 2.0)..=g.kind.spread.0 / 2.0)).into();

			let vel = ship_vel
				+ (Matrix2::from_angle(-ship_ang + spread)
					* Vector2 {
						x: 0.0,
						y: g.kind.projectile.speed
							+ rng.gen_range(
								-g.kind.projectile.speed_rng..=g.kind.projectile.speed_rng,
							),
					});

			let p_r = RigidBodyBuilder::kinematic_velocity_based()
				.translation(vector![pos.x, pos.y])
				.rotation(-ship_ang.0)
				.linvel(vector![vel.x, vel.y]);

			let p_c = ColliderBuilder::ball(5.0)
				.sensor(true)
				.active_events(ActiveEvents::COLLISION_EVENTS);

			out.push(ProjectileBuilder {
				rigid_body: p_r,
				collider: p_c,
				sprite_texture: g.kind.projectile.sprite_texture,
				lifetime: g.kind.projectile.lifetime
					+ rng.gen_range(
						-g.kind.projectile.lifetime_rng..=g.kind.projectile.lifetime_rng,
					),
				size: g.kind.projectile.size
					+ rng.gen_range(-g.kind.projectile.size_rng..=g.kind.projectile.size_rng),
				damage: g.kind.projectile.damage, // TODO: kind as param to builder
				faction: self.faction,
			})
		}
		return out;
	}

	/// Apply the effects of all active controls
	pub fn apply_controls(&mut self, r: &mut RigidBody, t: f32) -> ShipTickResult {
		let ship_rot = util::rigidbody_rotation(r);
		let engine_force = ship_rot * t;

		if self.controls.thrust {
			for e in self.outfits.iter_engines() {
				r.apply_impulse(vector![engine_force.x, engine_force.y] * e.thrust, true);
			}
		}

		if self.controls.right {
			r.apply_torque_impulse(-500.0 * t, true);
		}

		if self.controls.left {
			r.apply_torque_impulse(500.0 * t, true);
		}

		let p = if self.controls.guns {
			self.fire_guns(r)
		} else {
			Vec::new()
		};

		for i in self.outfits.iter_guns() {
			i.cooldown -= t;
		}

		return ShipTickResult { projectiles: p };
	}

	pub fn get_sprite(&self, r: &RigidBody) -> Sprite {
		let ship_pos = util::rigidbody_position(r);
		let ship_rot = util::rigidbody_rotation(r);

		// Sprites point north at 0 degrees
		let ship_ang: Deg<f32> = ship_rot.angle(Vector2 { x: 0.0, y: 1.0 }).into();

		Sprite {
			pos: (ship_pos.x, ship_pos.y, 1.0).into(),
			texture: self.sprite_texture,
			angle: -ship_ang,
			size: self.size,

			children: if self.controls.thrust {
				Some(self.outfits.get_engine_flares())
			} else {
				None
			},
		}
	}
}