62 lines
2.0 KiB
JavaScript
62 lines
2.0 KiB
JavaScript
/*
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Copyright (c) 2020 Jean-Marc VIGLINO,
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released under the CeCILL-B license (French BSD license)
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(http://www.cecill.info/licences/Licence_CeCILL-B_V1-en.txt).
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*/
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import ol_particule_Base from './Base.js'
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/** Rain particules to display clouds over the map
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* @constructor
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* @extends {ol_particule_Base}
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* @param {*} options
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* @param {ol.Overlay} options.overlay
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* @param {ol.pixel} options.coordinate the position of the particule
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*/
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var ol_particule_Snow = class olparticuleSnow extends ol_particule_Base {
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constructor(options) {
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options = options || {};
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super(options);
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this.z = (Math.floor(Math.random() * 5) + 1) / 5;
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this.angle = Math.random() * Math.PI;
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// Snow fakes
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var canvas = document.createElement('canvas');
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canvas.width = 20;
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canvas.height = 20;
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var ctx = canvas.getContext('2d');
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var grd = ctx.createRadialGradient(10, 10, 0, 10, 10, 10);
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grd.addColorStop(0, "rgba(255, 255, 255,1)"); // white
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grd.addColorStop(.8, "rgba(210, 236, 242,.8)"); // bluish
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grd.addColorStop(1, "rgba(237, 247, 249,0)"); // lighter bluish
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this.image = canvas;
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ctx.fillStyle = grd;
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ctx.fillRect(0, 0, canvas.width, canvas.height);
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}
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/** Draw the particule
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* @param {CanvasRenderingContext2D } ctx
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*/
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draw(ctx) {
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ctx.save();
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ctx.translate(this.coordinate[0], this.coordinate[1]);
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ctx.globalAlpha = .4 + this.z / 2;
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ctx.scale(this.z, this.z);
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ctx.drawImage(this.image, -10, -10);
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ctx.restore();
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}
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/** Update the particule
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* @param {number} dt timelapes since last call
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*/
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update(dt) {
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var speed = this.getOverlay().get('speed') * dt / this.getOverlay()._fps * this.z * 5;
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var angle = this.getOverlay().get('angle');
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this.angle = this.angle + dt / this.getOverlay()._fps / 100;
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this.coordinate[0] += Math.sin(this.angle + this.z) * 2 + speed * Math.cos(angle);
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this.coordinate[1] += Math.cos(this.angle) + speed * Math.sin(angle);
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}
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}
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export default ol_particule_Snow
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