gravity/simulator.js

138 lines
3.8 KiB
JavaScript

import { Display } from './display.js';
import { Overlay } from './overlay.js';
import { Pointer } from './pointer.js';
import { Objects } from './objects.js';
import { Toolbar } from './toolbar.js';
import { PlayPause } from './tool/play-pause.js';
import { Zoom } from './tool/zoom.js';
import { ModeSwitch } from './tool/modes.js';
import { Options } from './tool/options.js';
import {
SCALE_POWER_MAX,
SCALE_POWER_MIN,
DISPLAY_CURRENT_SCALE,
DISPLAY_CURRENT_MODE,
MOTION_TIME_SCALE,
MODE_PAN_VIEW,
} from './config.js';
export class Sim {
info = {};
time = undefined;
nextZoom = undefined;
playing = true;
display = undefined;
overlay = undefined;
pointer = undefined;
objects = undefined;
toolbar = undefined;
toolbar2 = undefined;
isCurrentMode = () => false;
getOption = () => undefined;
init(divId) {
this.divId = divId;
const div = document.getElementById(this.divId);
this.div = div;
this.display = new Display(this);
this.overlay = new Overlay(this);
this.objects = new Objects(this);
this.toolbar = new Toolbar(this);
// Set up toolbar
this.toolbar.addTool(new Zoom(this.toolbar));
this.toolbar.addTool(new PlayPause(this.toolbar));
this.toolbar.addTool(new ModeSwitch(this.toolbar));
// Set up second toolbar
this.toolbar2 = new Toolbar(this).topRight();
this.toolbar2.addTool(new Options(this.toolbar));
this.pointer = new Pointer(this);
// Initiate main loop
this.time = document.timeline.currentTime;
requestAnimationFrame(t => this.loop(t));
}
// It's better not to change the scale in the middle of possible frame calculations,
// so use this to schedule it and let the event loop pick it up.
// velocity should be in Sim coordinate scale
scheduleZoom({x, y}, factor, velocity) {
this.nextZoom = {x, y, factor, velocity};
}
// x, y should be in Sim coordinates
// velocity should be in Sim coordinate scale
zoom({x, y, factor, velocity}) {
// x, y are the mouse coordinates, which should be the center of the new view frame
// the new view origin should be x, y minus half the new view width and height
// compute new scale
this.display.scalePower += factor;
// TODO: Lossy rescaling to expand zoom range
if (this.display.scalePower > SCALE_POWER_MAX) this.display.scalePower = SCALE_POWER_MAX;
if (this.display.scalePower < SCALE_POWER_MIN) this.display.scalePower = SCALE_POWER_MIN;
// compute coordinates of new view frame
this.display.viewOrigin.x = x - this.display.width / 2;
this.display.viewOrigin.y = y - this.display.height / 2;
this.pointer.clearPointerHistory();
if (this.playing && velocity) {
this.pointer.panning = {
velocity: {
x: -velocity.x,
y: -velocity.y,
}
};
}
}
// Transform display coordinates to simulator coordinates using scale and viewOrigin
screenToSim(x, y) {
return this.display.screenToSim(x, y);
}
play() {
this.playing = true;
}
pause() {
this.playing = false;
}
// Main loop
loop(currentTime) {
const elapsedTime = (currentTime - this.time) * MOTION_TIME_SCALE;
this.time = currentTime;
if (DISPLAY_CURRENT_MODE) {
this.info['Mode'] = this.getCurrentMode();
}
if (this.nextZoom) {
this.zoom(this.nextZoom);
this.nextZoom = undefined;
}
if (DISPLAY_CURRENT_SCALE) {
const scale = 2 ** Math.abs(this.display.scalePower);
this.info['Scale'] = this.display.scalePower >= 0 ? `${scale}` : `1/${scale}`;
}
this.pointer.computeFrame(elapsedTime);
this.objects.computeFrame(elapsedTime);
this.overlay.updateDraggable();
this.overlay.renderInfo();
this.display.fillCanvas();
this.display.drawObjects();
requestAnimationFrame(t => this.loop(t));
}
}