129 lines
4.2 KiB
JavaScript
129 lines
4.2 KiB
JavaScript
import { Tool } from '../tool.js';
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import {
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TOOL_INFO_CLASSNAME,
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WIDE_CLASSNAME,
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ZOOM_IN_FACTOR,
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ZOOM_OUT_FACTOR,
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} from '../config.js';
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export class Zoom extends Tool {
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get displayScale() {
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return this.sim.getScaleDisplay();
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}
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get displayScaleText() {
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return `Scale: ${this.displayScale}`;
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}
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constructor(toolbar) {
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super(toolbar);
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const currentScale = document.createElement('button')
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const zoomOut = document.createElement('button');
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const zoomIn = document.createElement('button');
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const zoomAll = document.createElement('button');
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const zeroVelocity = document.createElement('button');
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this.div.appendChild(currentScale);
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this.div.appendChild(zoomOut);
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this.div.appendChild(zoomIn);
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this.div.appendChild(zoomAll);
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this.div.appendChild(zeroVelocity);
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zoomAll.classList.add(WIDE_CLASSNAME);
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zeroVelocity.classList.add(WIDE_CLASSNAME);
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currentScale.classList.add(WIDE_CLASSNAME);
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currentScale.classList.add(TOOL_INFO_CLASSNAME);
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zoomOut.innerHTML = 'Zoom<br>Out';
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zoomIn.innerHTML = 'Zoom<br>In';
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zoomAll.innerHTML = 'Zoom to Fit';
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zeroVelocity.innerHTML = 'Zero Momentum';
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currentScale.innerHTML = this.displayScaleText;
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this.sim.onZoom(() => {
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currentScale.innerHTML = this.displayScaleText;
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});
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zoomOut.addEventListener('click', () => {
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// Aim at center of view
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const x = this.sim.display.width * this.sim.display.scale / 2;
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const y = this.sim.display.height * this.sim.display.scale / 2;
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this.sim.scheduleZoom(this.sim.screenToSim(x, y), ZOOM_OUT_FACTOR);
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});
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zoomIn.addEventListener('click', () => {
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// Aim at center of view
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const x = this.sim.display.width * this.sim.display.scale / 2;
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const y = this.sim.display.height * this.sim.display.scale / 2;
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this.sim.scheduleZoom(this.sim.screenToSim(x, y), ZOOM_IN_FACTOR);
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});
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zoomAll.addEventListener('click', () => {
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// Determine bounding box
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const box = this.sim.objects.boundingBox;
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const x = (box.start.x + box.end.x) / 2;
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const y = (box.start.y + box.end.y) / 2;
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const widthRatio = Math.abs(box.start.x - box.end.x) / this.sim.display.width;
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const heightRatio = Math.abs(box.start.y - box.end.y) / this.sim.display.height;
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const biggerRatio = Math.max(widthRatio, heightRatio);
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const base2factor = Math.log(1/biggerRatio) / Math.log(2) - 1;
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const factor = Math.floor(base2factor);
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// Determine average momentum and set panning velocity to match
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const netMomentum = {x: 0, y: 0};
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let totalMass = 0;
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let count = 0;
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this.sim.objects.forEachObject(obj => {
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count++;
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netMomentum.x += obj.mass * obj.velocity.x;
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netMomentum.y += obj.mass * obj.velocity.y;
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totalMass += obj.mass;
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});
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if (!count) {
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return;
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}
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const netVelocity = {
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x: netMomentum.x / totalMass,
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y: netMomentum.y / totalMass,
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};
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this.sim.scheduleZoom({x, y}, factor, netVelocity)
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});
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zeroVelocity.addEventListener('click', () => {
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// TODO: Zero net angular momentum
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// Determine center of mass
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const { totalMass, centerOfMass } =
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this.sim.objects.computeSystemCenter();
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// Determine total angular momentum
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const netAngularMomentum = this.sim.objects
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.computeSystemAngularMomentum(centerOfMass);
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console.log('net angular momentum', netAngularMomentum);
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const netAngularVelocity = netAngularMomentum / totalMass;
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console.log('net angular velocity', netAngularVelocity);
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// TODO: Camera rotation
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// Determine average momentum
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const netMomentum = this.sim.objects.reduce((acc, obj) => ({
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x: acc.x + obj.mass * obj.velocity.x,
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y: acc.y + obj.mass * obj.velocity.y,
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}), { x: 0, y: 0 });
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const netVelocity = {
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x: netMomentum.x / totalMass,
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y: netMomentum.y / totalMass,
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};
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// Apply offset to all object velocities
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this.sim.objects.forEachObject(obj => {
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obj.velocity.x -= netVelocity.x;
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obj.velocity.y -= netVelocity.y;
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});
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// Cancel panning
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this.sim.panning = undefined;
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});
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}
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}
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