dust/js/animation2b.js

import Rx, { Observable } from 'rxjs';
import Particle from './particle';
import Store from './store';
import Controls from './controls';
import { CONTROLS } from './enums';

function Animation2b() {
    this.options = {
        count: 1,
        maxCount: 1000,
        speed: 4
    };

    this.container = document.getElementById('animation2b');
    this.bounds = this.container.getBoundingClientRect();

    this.particles = [];
    this.globalGrid = createGlobalGrid(this.container, this.bounds);

    const controls = new Controls(
        document.getElementById('controls2b'),
        this.options
    );

    controls.mount().subscribe(this.subscriber.bind(this));

    this.updateAnimating(this.options.animating);
    this.updateCount(this.options.count);
};

Animation2b.prototype.subscriber = function({ key, value }) {
    switch(key) {
        case CONTROLS.ANIMATING: this.updateAnimating(value); break;
        case CONTROLS.COUNT: this.updateCount(value); break;
        case CONTROLS.SPEED: this.updateSpeed(value); break;
    }
}

Animation2b.prototype.nextFrame = function() {
    this.particles.forEach(p => p.nextFrame());
}

Animation2b.prototype.updateAnimating = function(isAnimating) {
    this.options.animating = isAnimating;

    if (isAnimating) {
        const fps$ = Rx.Observable.interval(1000 / 32)
            .takeWhile(_ => this.options.animating);

        fps$.subscribe(this.nextFrame.bind(this));
    }
}

Animation2b.prototype.updateCount = function(count) {
    while (this.particles.length > count) {
        delete this.particles.pop().remove();
    }

    while (this.particles.length < count) {
        const p = new Particle(this.container, this.bounds, this.options, this.globalGrid);
        this.particles.push(p);
    }
}

Animation2b.prototype.updateSpeed = function(value) {
    this.options.speed = value;
    this.particles.forEach(p => p.updateConfig({ speed: value }));
}

function createGlobalGrid(container, bounds) {
    const grid = {};
    const gridSize = 5;

    const hazards = [
        { x: 100, y: 100, w: 200, h: 200 },
        { x: 600, y: 200, w: 200, h: 200 },
    ];

    return hazards.reduce((acc, { x, y, w, h }) => {
        const div = document.createElement('div');
        div.className = 'hazard';
        div.style.left = `${x}px`;
        div.style.top = `${y}px`;
        div.style.height = `${h}px`;
        div.style.width = `${w}px`;
        container.appendChild(div);

        for (let i = x; i <= (x + w); i += gridSize) {
            for (let j = y; j <= (y + h); j += gridSize) {
                if (acc[i] === undefined) {
                    acc[i] = {};
                }

                if (acc[i][j] !== undefined) {
                    continue;
                }

                const dot = document.createElement('dot');
                dot.className = 'hazard-dot';
                dot.style.left = `${i - x}px`;
                dot.style.top = `${j - y}px`;
                div.appendChild(dot);

                acc[i][j] = true;
            }
        }


        return acc;
    }, {});
}

export default Animation2b;