rust-rl/src/particle_system.rs
Llywelwyn b6522d42c3 tweaks
changed placeholder player name, suppressed some dead code warnings
2023-07-09 23:08:58 +01:00

108 lines
4.1 KiB
Rust

use super::{ParticleLifetime, Position, Renderable, Rltk};
use rltk::RGB;
use specs::prelude::*;
// For things which will happen frequently - i.e. attacking.
pub const DEFAULT_PARTICLE_LIFETIME: f32 = 150.0;
// For exceptional things, like large AOEs, to make sure the
// player can actually see what's being impacted - i.e. fireball.
pub const LONG_PARTICLE_LIFETIME: f32 = 300.0;
/// Runs each tick, deleting particles who are past their expiry.
// Should make an addition to this to also spawn delayed particles,
// running through a list and removing the frame_time_ms from the
// delay. When delay is <= 0, make a particle_builder.request for
// the particle.
pub fn cull_dead_particles(ecs: &mut World, ctx: &Rltk) {
let mut dead_particles: Vec<Entity> = Vec::new();
{
// Age out particles
let mut particles = ecs.write_storage::<ParticleLifetime>();
let entities = ecs.entities();
for (entity, mut particle) in (&entities, &mut particles).join() {
particle.lifetime_ms -= ctx.frame_time_ms;
if particle.lifetime_ms < 0.0 {
dead_particles.push(entity);
}
}
}
for dead in dead_particles.iter() {
ecs.delete_entity(*dead).expect("Particle will not die");
}
}
struct ParticleRequest {
x: i32,
y: i32,
fg: RGB,
bg: RGB,
glyph: rltk::FontCharType,
lifetime: f32,
}
pub struct ParticleBuilder {
requests: Vec<ParticleRequest>,
}
impl ParticleBuilder {
#[allow(clippy::new_without_default)]
pub fn new() -> ParticleBuilder {
ParticleBuilder { requests: Vec::new() }
}
/// Makes a single particle request.
pub fn request(&mut self, x: i32, y: i32, fg: RGB, bg: RGB, glyph: rltk::FontCharType, lifetime: f32) {
self.requests.push(ParticleRequest { x, y, fg, bg, glyph, lifetime });
}
// Makes a particle request in the shape of an 'x'. Sort of.
pub fn request_star(&mut self, x: i32, y: i32, fg: RGB, bg: RGB, glyph: rltk::FontCharType, lifetime: f32) {
self.request(x, y, fg, bg, glyph, lifetime * 2.0);
self.request(x + 1, y + 1, fg, bg, rltk::to_cp437('/'), lifetime);
self.request(x + 1, y - 1, fg, bg, rltk::to_cp437('\\'), lifetime);
self.request(x - 1, y + 1, fg, bg, rltk::to_cp437('\\'), lifetime);
self.request(x - 1, y - 1, fg, bg, rltk::to_cp437('/'), lifetime);
}
/// Makes a particle request in the shape of a +.
#[allow(dead_code)]
pub fn request_plus(&mut self, x: i32, y: i32, fg: RGB, bg: RGB, glyph: rltk::FontCharType, lifetime: f32) {
self.request(x, y, fg, bg, glyph, lifetime * 2.0);
self.request(x + 1, y, fg, bg, rltk::to_cp437('─'), lifetime);
self.request(x - 1, y, fg, bg, rltk::to_cp437('─'), lifetime);
self.request(x, y + 1, fg, bg, rltk::to_cp437('│'), lifetime);
self.request(x, y - 1, fg, bg, rltk::to_cp437('│'), lifetime);
}
}
pub struct ParticleSpawnSystem {}
impl<'a> System<'a> for ParticleSpawnSystem {
#[allow(clippy::type_complexity)]
type SystemData = (
Entities<'a>,
WriteStorage<'a, Position>,
WriteStorage<'a, Renderable>,
WriteStorage<'a, ParticleLifetime>,
WriteExpect<'a, ParticleBuilder>,
);
fn run(&mut self, data: Self::SystemData) {
let (entities, mut positions, mut renderables, mut particles, mut particle_builder) = data;
for new_particle in particle_builder.requests.iter() {
let p = entities.create();
positions.insert(p, Position { x: new_particle.x, y: new_particle.y }).expect("Could not insert position");
renderables
.insert(
p,
Renderable { fg: new_particle.fg, bg: new_particle.bg, glyph: new_particle.glyph, render_order: 0 },
)
.expect("Could not insert renderables");
particles
.insert(p, ParticleLifetime { lifetime_ms: new_particle.lifetime })
.expect("Could not insert lifetime");
}
particle_builder.requests.clear();
}
}