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use std::f64::consts::PI;
use log::debug;
use wasm_bindgen::prelude::*;
use web_sys::{CanvasRenderingContext2d, HtmlCanvasElement, HtmlElement};
use crate::JSResult;
use crate::line::Line;
use crate::point::Point;
pub const TAU: f64 = PI * 2.0;
pub const MAX_SPEED: f64 = 0.01;
const VELVEC_SCALE: f64 = 3.0;
#[derive(Debug)]
pub struct State {
canvas: HtmlCanvasElement,
ctx: CanvasRenderingContext2d,
fps: HtmlElement,
pub points: Vec<Point>,
last_time: Option<f64>,
inter_count: u16,
}
impl State {
pub fn new(canvas: HtmlCanvasElement, fps: HtmlElement) -> JSResult<Self> {
debug!("State::new()");
let ctx: CanvasRenderingContext2d = canvas
.get_context("2d")?
.expect("2d context on canvas")
.dyn_into()?;
ctx.scale(canvas.width().into(), canvas.height().into())?;
Ok(Self {
canvas,
ctx,
fps,
points: vec![],
last_time: None,
inter_count: 1,
})
}
pub fn render_frame(&mut self, t: f64) -> JSResult<()> {
if let Some(last_time) = self.last_time {
if t > last_time {
let ic: f64 = self.inter_count.into();
let val: f64 = (1_000.0 * ic / (t - last_time)).trunc();
self.fps.set_text_content(Some(val.to_string().as_str()));
self.inter_count = 1;
} else {
self.inter_count += 1;
}
}
self.last_time = Some(t);
self.ctx.clear_rect(
0.0,
0.0,
self.canvas.width().into(),
self.canvas.height().into(),
);
self.render_points()?;
// poly finding assumes sorted
self.points.sort_by(|a, b| {
if a.y > b.y {
std::cmp::Ordering::Greater
} else if a.y == b.y {
std::cmp::Ordering::Equal
} else {
std::cmp::Ordering::Less
}
});
let poly_points = self.find_poly();
self.ctx.set_line_width(0.005);
let mut iter = poly_points.into_iter();
let mut last = iter.next().ok_or("no poly points")?;
for p in iter {
self.ctx.begin_path();
self.ctx.move_to(last.x, last.y);
self.ctx.set_stroke_style_str(&last.color);
self.ctx.line_to(p.x, p.y);
self.ctx.stroke();
last = p;
}
Ok(())
}
pub fn update(&mut self) -> JSResult<()> {
if self.bounce_points() {
//debug!("point bounced");
}
self.move_points();
Ok(())
}
pub fn set_dot_count(&mut self, n: usize) {
self.points = (0..n)
.map(|_| Point::new(fastrand::f64(), fastrand::f64()))
.collect();
}
fn render_points(&self) -> JSResult<()> {
for p in &self.points {
self.ctx.set_fill_style_str(&p.color);
self.ctx.begin_path();
self.ctx.arc(p.x, p.y, p.radius, 0.0, TAU)?;
self.ctx.fill();
self.ctx.set_line_width(0.005);
self.ctx.set_stroke_style_str(&p.color);
self.ctx.begin_path();
self.ctx.move_to(p.x, p.y);
self.ctx.line_to(
p.x + p.speed_x() * VELVEC_SCALE,
p.y + p.speed_y() * VELVEC_SCALE,
);
self.ctx.stroke();
}
Ok(())
}
pub fn find_poly(&self) -> Vec<&Point> {
find_poly_helper(&self.points)
}
fn bounce_points(&mut self) -> bool {
bounce_points_helper(&mut self.points)
}
fn move_points(&mut self) {
move_points_helper(&mut self.points);
}
}
fn bounce_points_helper(points: &mut Vec<Point>) -> bool {
let mut did_bounce = false;
for p in points {
let x = p.x + p.speed_x();
let y = p.y + p.speed_y();
if x < 0.0 || x >= 1.0 {
p.heading = PI - p.heading;
did_bounce = true;
} else if y < 0.0 || y >= 1.0 {
p.heading = -p.heading;
did_bounce = true;
}
}
did_bounce
}
fn move_points_helper(points: &mut Vec<Point>) {
for p in points {
p.x += p.speed_x();
p.y += p.speed_y();
}
}
fn find_poly_helper(points: &Vec<Point>) -> Vec<&Point> {
let p1 = Point::new(0.0, 0.0);
let p2 = Point::new(1.0, 0.0);
let mut last_line = Line::new(&p1, &p2);
let mut xxx = 100;
let mut res = vec![&points[0]];
loop {
let last = res.last().expect("something in res");
let mut min_theta = TAU;
let mut min_p = &points[0];
for p in points {
if !last.equal_pos(p) {
let l2 = Line::new(last, p);
let theta = last_line.angle_between(&l2);
if theta < min_theta {
min_theta = theta;
min_p = p;
}
}
}
last_line = Line::new(res.last().expect("something in res"), min_p);
res.push(min_p);
xxx -= 1;
if xxx == 0 || res[0].equal_pos(res.last().expect("something in res")) {
break;
}
}
res
}
#[cfg(test)]
mod test {
use super::*;
use std::hint::black_box;
use std::time::Instant;
fn update(points: &mut Vec<Point>) {
black_box(bounce_points_helper(points));
black_box(move_points_helper(points));
points.sort_by(|a, b| {
if a.y > b.y {
std::cmp::Ordering::Greater
} else if a.y == b.y {
std::cmp::Ordering::Equal
} else {
std::cmp::Ordering::Less
}
});
black_box(find_poly_helper(points));
}
#[test]
fn bench_update() {
println!("in bench_update(), you remembered cargo test -- --nocapture.");
let point_count = 40;
let iters = 10_000;
let mut points: Vec<Point> = (0..point_count)
.map(|_| Point::new(fastrand::f64(), fastrand::f64()))
.collect();
let start = Instant::now();
for _ in 0..iters {
black_box(update(&mut points));
}
let delta = start.elapsed();
let smaller: f64 = u32::try_from(delta.as_millis()).unwrap().into();
let iters_per_ms = Into::<f64>::into(iters) / smaller;
println!("{iters} iters in {smaller} ms ({iters_per_ms:0.2} iters per ms)");
}
}
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