143 lines
3.6 KiB
Rust

use galactica_content::{CollapseEvent, Ship};
use nalgebra::{Point2, Vector2};
use rand::{rngs::ThreadRng, Rng};
use rapier2d::{
dynamics::RigidBodyHandle,
geometry::{Collider, ColliderHandle},
};
use crate::{
data::ShipData,
phys::{objects::PhysEffect, physsim::NewObjects, PhysStepResources, PhysWrapper},
};
#[derive(Debug, Clone)]
pub(super) struct ShipCollapseSequence {
rng: ThreadRng,
/// The total length of this collapse sequence
total_length: f32,
/// How many seconds we've spent playing this sequence
elapsed: f32,
}
impl ShipCollapseSequence {
pub(super) fn new(total_length: f32) -> Self {
Self {
rng: rand::thread_rng(),
total_length,
elapsed: 0.0,
}
}
/// Has this collapse sequence fully played out?
pub fn is_done(&self) -> bool {
self.elapsed >= self.total_length
}
/// Pick a random points inside a ship's collider
fn random_in_ship(&mut self, ship: &Ship, collider: &Collider) -> Vector2<f32> {
let mut y = 0.0;
let mut x = 0.0;
let mut a = false;
while !a {
x = self.rng.gen_range(-1.0..=1.0) * ship.size / 2.0;
y = self.rng.gen_range(-1.0..=1.0) * ship.size * ship.sprite.aspect / 2.0;
a = collider.shape().contains_local_point(&Point2::new(x, y));
}
Vector2::new(x, y)
}
/// Step this sequence `t` seconds
pub(super) fn step(
&mut self,
res: &mut PhysStepResources,
wrapper: &mut PhysWrapper,
new: &mut NewObjects,
ship_data: &ShipData,
rigid_body_handle: RigidBodyHandle,
collider_handle: ColliderHandle,
) {
let rigid_body = wrapper.get_rigid_body(rigid_body_handle).unwrap().clone();
let collider = wrapper.get_collider(collider_handle).unwrap().clone();
let ship_content = ship_data.get_content();
let ship_pos = rigid_body.translation();
let ship_rot = rigid_body.rotation();
// The fraction of this collapse sequence that has been played
let frac_done = self.elapsed / self.total_length;
// TODO: slight random offset for event effects
// Trigger collapse events
for event in &ship_content.collapse.events {
match event {
CollapseEvent::Effect(event) => {
if (event.time > self.elapsed && event.time <= self.elapsed + res.t)
|| (event.time == 0.0 && self.elapsed == 0.0)
// ^^ Don't miss events scheduled at the very start of the sequence!
{
for spawner in &event.effects {
for _ in 0..spawner.count as usize {
let pos: Vector2<f32> = if let Some(pos) = spawner.pos {
Vector2::new(pos.x, pos.y)
} else {
self.random_in_ship(&ship_content, &collider)
};
let pos = ship_pos + (ship_rot * pos);
new.effects.push(PhysEffect::new(
wrapper,
spawner.effect.clone(),
pos,
rigid_body_handle,
None,
));
}
}
}
}
}
}
// Create collapse effects
for spawner in &ship_content.collapse.effects {
// Probability of adding an effect instance this frame.
// The area of this function over [0, 1] should be 1.
let pdf = |x: f32| {
let f = 0.2;
let y = if x < (1.0 - f) {
let x = x / (1.0 - f);
(x * x + 0.2) * 1.8 - f
} else {
1.0
};
return y;
};
let p_add = (res.t / self.total_length) * pdf(frac_done) * spawner.count;
if self.rng.gen_range(0.0..=1.0) <= p_add {
let pos = if let Some(pos) = spawner.pos {
Vector2::new(pos.x, pos.y)
} else {
self.random_in_ship(&ship_content, &collider)
};
// Position, adjusted for ship rotation
let pos = ship_pos + (ship_rot * pos);
new.effects.push(PhysEffect::new(
wrapper,
spawner.effect.clone(),
pos,
rigid_body_handle,
None,
));
}
}
self.elapsed += res.t;
}
}