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Adjustments to panning; Added Selection Box

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This commit is contained in:
Ladd 2026-01-02 11:51:52 -06:00
parent fe7e9f43ad
commit 6922011ca7
14 changed files with 672 additions and 435 deletions
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23
Layout.md
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@ -1,23 +0,0 @@
Overlay > Info Box
Each toolbar gives itself a header tool which expands/collapses the toolbar.
- Toolbar Group: Left Side
- Toolbar: Tools
- Tool: Zoom
- Toolbar: Modes
- Tool: Mode Switch
- Toolbar: Utils
- Tool: Utility Tool
- Toolbar Group: Right Side
- Toolbar: Options
- Tool: Options Tool
- Section: Pause During
- Section: Display
- Section: Collision
- Toolbar: Params
- Tool: Options Tool
- Section: Param
- Toolbar: Debug
- Tool: Options Tool
- Section: Debug

81
Readme.md
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@ -15,27 +15,66 @@ Screenshots
TODO
----
- [ ] Selection Box
- [ ] Object List
- [ ] Object Detail
- [ ] Left Button Panning
- [ ] Middle Button Pause
- [ ] Parameter Slider (Invisible, mouse/touch drag)
- [ ] Grid
- [ ] Zoom Easing
- [ ] 2-touch Pan & Zoom
- Either continuous zoom, or discrete with animation of bounding box proposed changes
- [ ] Multi-touch Mass Create
- [ ] Camera Rotation
- [x] Selection Box
- [ ] Enhancement: Create Vector class and refactor to use
- [ ] Feature: Object List
- [ ] Feature: Object Detail
- [ ] Enhancement: Handle pointerleave or other mechanism when window loses focus
- [ ] Enhancement: Calculate Work as FxD as measure of energy flux
- [ ] Feature: Automatically slow time when energy flux is greater
- [ ] Enhancement: Add z-axis (Initially nothing changes, z = 0)
- [ ] Feature: Isometric 3d View
- [ ] Feature: Grid
- [ ] Feature: Polar Coordinates
- [ ] Feature: Cylindrical Coordinates
- [ ] Feature: Spherical Coordinates
- [ ] Feature: Camera Velocity Display
- [ ] Enhancement: World State Snapshots
- [ ] Feature: List / Save / Load World States
- [ ] Feature: Left Button Panning
- [ ] Feature: Middle Button Pause
- [ ] Feature: Parameter Slider (Invisible, mouse/touch drag)
- [ ] Enhancement: Zoom Easing
- [ ] Feature: 2-touch Pan & Zoom
Either continuous zoom, or discrete with animation of bounding box proposed changes
- [ ] Feature: Multi-touch Mass Create
- [ ] Feature: Camera Rotation
- [ ] 2-touch Rotation
- [ ] Spinning Frame
- [ ] Undo feature:
- [ ] Feature: Undo
- [ ] Undo "Clear Traces" Action
- [ ] Undo "Reset
- [ ] Time Control: Reverse Time
- [ ] Lossy Rescaling To Widen Zoom (Handling overflow/underflow)
- [ ] Track farthest reaches, min/max in each dimension (x, y)
- [ ] Calculate Work as FxD as measure of energy flux
- [ ] Option to automatically slow time when energy flux is greater
- [ ] Handle pointerleave or other mechanism when window loses focus
- [ ] Verify stationary pointer leads to zero pointer velocity
- [ ] In general have a user action history
- [ ] Point-in-time restoral of world state (Marked points, i.e. Snapshots)
- [ ] Feature: Time Control: Reverse Time
- [ ] Feature: Lossy Rescaling To Widen Zoom (Handling overflow/underflow)
- [ ] Enhancement: Track farthest reaches, min/max in each dimension (x, y)
- [x] Task: Verify stationary pointer leads to zero pointer velocity

89
display.js
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@ -22,6 +22,45 @@ export class Display {
window.addEventListener('resize', () => this.fullscreen());
}
frame(elapsedTime) {
const {
touchStart: start,
touchLatest: latest,
} = this.sim.pointer ?? {};
// Direct translate, unless using fast panning
if (start && latest && !this.sim.getOption('compensate.fastPanning')) {
this.viewOrigin.x = start.viewOrigin.x - (latest.x - start.x) / this.scale;
this.viewOrigin.y = start.viewOrigin.y - (latest.y - start.y) / this.scale;
}
// Apply update to viewOrigin based on panning
if (this.sim.panning && !this.sim.panning.paused) {
// elapsedTime is scaled by time scale, is that what we want?
// Yes because if panning.velocity == obj.velocity, object should stay in view
this.viewOrigin.x += this.sim.panning.velocity.x * elapsedTime;
this.viewOrigin.y += this.sim.panning.velocity.y * elapsedTime;
}
// Update what's considered start
if (start && latest) {
start.viewOrigin = {...this.viewOrigin};
start.x = latest.x;
start.y = latest.y;
}
if (this.sim.getOption('debug.panningInfo')) {
const {x, y} = this.sim.panning?.velocity ?? {};
this.sim.info['Panning Velocity'] = [`${x?.toPrecision(6)}, `, y?.toPrecision(6)];
const {centerOfMass} = this.sim.system.computeSystemCenter();
this.sim.info['Center of Mass'] = [`${centerOfMass.x.toPrecision(6)}, `, centerOfMass.y.toPrecision(6)];
this.sim.info['Net Angular Momentum'] = this.sim.system.computeSystemAngularMomentum().toPrecision(6);
}
// Clear canvas in preparation for other modules to render this frame
this.fillCanvas();
}
get scale() {
return 2 ** this.scalePower;
}
@ -67,7 +106,9 @@ export class Display {
ctx.fillRect(this.viewOrigin.x, this.viewOrigin.y, this.width, this.height);
}
drawArrow(startX, startY, endX, endY, {style, width, arrowhead, arrowheadLength, fill, ifShort}) {
drawArrow(startX, startY, endX, endY, {
style, width, arrowhead, arrowheadLength, fill, ifShort
}) {
const ctx = this.ctx;
ctx.strokeStyle = style;
// Keep arrows at normal scale
@ -135,47 +176,9 @@ export class Display {
ctx.resetTransform();
}
frame(elapsedTime) {
const {
touchStart: start,
touchLatest: latest,
} = this.sim.pointer ?? {};
if (start && latest) {
// Direct translate
this.viewOrigin.x = start.viewOrigin.x - (latest.x - start.x) / this.scale;
this.viewOrigin.y = start.viewOrigin.y - (latest.y - start.y) / this.scale;
}
let pdx = 0;
let pdy = 0;
if (this.sim.panning && !this.sim.panning.paused) {
// Apply update to viewOrigin based on panning
// TODO: elapsedTime is scaled by time scale, is that what we want?
pdx = this.sim.panning.velocity.x * elapsedTime;
pdy = this.sim.panning.velocity.y * elapsedTime;
}
this.viewOrigin.x += pdx;
this.viewOrigin.y += pdy;
if (start && latest) {
// Update what's considered start
start.viewOrigin = {...this.viewOrigin};
start.x = latest.x;
start.y = latest.y;
}
if (this.sim.getOption('debug.panningInfo')) {
const {x, y} = this.sim.panning?.velocity ?? {};
this.sim.info['Panning Velocity'] = [`${x?.toPrecision(6)}, `, y?.toPrecision(6)];
const { centerOfMass } = this.sim.system.computeSystemCenter();
this.sim.info['Center of Mass'] = [`${centerOfMass.x.toPrecision(6)}, `, centerOfMass.y.toPrecision(6)];
this.sim.info['Net Angular Momentum'] = this.sim.system.computeSystemAngularMomentum().toPrecision(6);
}
// Clear canvas in preparation for other modules to render this frame
this.fillCanvas();
drawBox({start, end}) {
const ctx = this.ctx;
ctx.strokeStyle = 'rgb(0, 255, 0)';
ctx.strokeRect(start.x, start.y, end.x - start.x, end.y - start.y);
}
}

27
object.js
View File

@ -28,6 +28,9 @@ export class MassObject {
history = [];
alive = true;
currentPosition = undefined;
currentAcceleration = undefined;
constructor(sim, x, y) {
this.sim = sim;
this.id = crypto.randomUUID();
@ -192,12 +195,16 @@ export class MassObject {
const arrowDirection = Math.atan2(velocity.y, velocity.x);
// Prevent negative numbers by adding 1
// TODO: Make logarithmic vector length scale optional
const arrowLength = Math.log10(speed + 1) * vecScale + radius;
const endVx = x + arrowLength * Math.cos(arrowDirection);
const endVy = y + arrowLength * Math.sin(arrowDirection);
const arrowLength = Math.log10(speed + 1) * vecScale;
const offsetX = radius * Math.cos(arrowDirection);
const offsetY = radius * Math.sin(arrowDirection);
const startVx = x + offsetX;
const startVy = y + offsetY;
const endVx = startVx + arrowLength * Math.cos(arrowDirection);
const endVy = startVy + arrowLength * Math.sin(arrowDirection);
const style = VELOCITY_VECTOR_COLOR === 'object color' ?
`rgb(${r}, ${g}, ${b})` : VELOCITY_VECTOR_COLOR;
sim.display.drawArrow(x, y, endVx, endVy, {
sim.display.drawArrow(startVx, startVy, endVx, endVy, {
style,
width: VELOCITY_VECTOR_WIDTH,
arrowhead: VELOCITY_VECTOR_ARROWHEAD,
@ -213,13 +220,17 @@ export class MassObject {
this.sim.display.scale;
const arrowDirection = Math.atan2(acceleration.y, acceleration.x);
// Prevent negative numbers by adding 1
const arrowLength = Math.log10(accelerationMagnitude + 1) * vecScale + radius;
const arrowLength = Math.log10(accelerationMagnitude + 1) * vecScale;
//const arrowLength = accelerationMagnitude * vecScale;
const endAx = x + arrowLength * Math.cos(arrowDirection);
const endAy = y + arrowLength * Math.sin(arrowDirection);
const offsetX = radius * Math.cos(arrowDirection);
const offsetY = radius * Math.sin(arrowDirection);
const startAx = x + offsetX;
const startAy = y + offsetY;
const endAx = startAx + arrowLength * Math.cos(arrowDirection);
const endAy = startAy + arrowLength * Math.sin(arrowDirection);
const style = ACCELERATION_VECTOR_COLOR === 'object color' ?
`rgb(${r}, ${g}, ${b})` : ACCELERATION_VECTOR_COLOR;
sim.display.drawArrow(x, y, endAx, endAy, {
sim.display.drawArrow(startAx, startAy, endAx, endAy, {
style,
width: ACCELERATION_VECTOR_WIDTH,
arrowhead: ACCELERATION_VECTOR_ARROWHEAD,

129
options-1.js Normal file
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@ -0,0 +1,129 @@
import {
EVENT_OPTION_SET,
OBJECT_MAGIC_PROP_PREFIX,
} from './config.js';
export class Options {
sim = undefined;
options = undefined;
values = {};
undefinedObj = {[OBJECT_MAGIC_PROP_PREFIX + 'undefined']: true};
nullObj = {[OBJECT_MAGIC_PROP_PREFIX + 'null']: true};
getStorageKey(path) {
return `${path}:options`;
}
constructor(sim, options) {
this.sim = sim;
this.options = options;
// Global methods to get/set current option values
this.sim.getOption = (path) => this.getOption(path);
this.sim.setOption = (path, value) => this.setOption(path, value);
this.sim.onOptionSet = (path, cb) => this.onOptionSet(path, cb);
// Initialize values from localStorage
for (const groupName of Object.keys(options)) {
for (const [name, [, , defaultValue]] of Object.entries(this.options[groupName])) {
const path = [groupName, name].join('.');
let value = this.getFromLocalStorage(path);
if (value === undefined) {
value = defaultValue;
}
this.values[path] = value;
}
}
}
toStored(value) {
if (value === undefined) {
// Do we want to interpret this as removing from storage?
// Let's just treat it as a value for now;
// Semantically it works because when retrieved, it will return undefined,
// which is the same result you get if the key is not set
return JSON.stringify(this.undefinedObj);
} else if (value === null) {
return JSON.stringify(this.nullObj);
}
return JSON.stringify(value);
}
// value: string
fromStored(value) {
if (value === null) {
return undefined;
} else if (value === JSON.stringify(this.undefinedObj)) {
return undefined;
} else if (value === JSON.stringify(this.nullObj)) {
return null;
}
return JSON.parse(value);
}
getFromLocalStorage(path) {
const storageKey = this.getStorageKey(path);
const value = this.fromStored(window.localStorage.getItem(storageKey));
this.values[path] = value;
return value;
}
getOption(path) {
const [groupName, name] = path.split('.');
const group = this.options[groupName];
const item = group[name];
const {type} = item;
const value = this.values[path];
switch (type) {
case 'number': return Number(value);
case 'boolean': return value === true || value === 'true';
default: {
console.log({
path, groupName, name,
group, item,
type, value
});
throw new Error('unknown option type');
}
}
}
setOption(path, value) {
this.values[path] = value;
const storageKey = this.getStorageKey(path);
window.localStorage.setItem(storageKey, this.toStored(value));
const e = new CustomEvent(EVENT_OPTION_SET, {detail: {path, value}});
this.sim.div.dispatchEvent(e);
}
// cb: (value) => undefined
onOptionSet(path, cb) {
this.sim.div.addEventListener(EVENT_OPTION_SET, (e) => {
if (path === e.detail.path) {
cb(e.detail.value);
}
});
}
getSection(sectionName) {
const section = this.options[sectionName];
const group = {
type: 'group',
name: sectionName,
title: section._title,
items: [],
};
for (const name in section) {
if (name.startsWith('_')) continue;
const [title, type, defaultValue, opts] = section[name];
group.items.push({
name,
type,
title,
default: defaultValue,
...opts
})
}
return group;
}
}

15
options.js
View File

@ -69,13 +69,22 @@ export class Options {
}
getOption(path) {
const [group, name] = path.split('.');
const {type} = this.options[group][name];
const [groupName, name] = path.split('.');
const group = this.options[groupName];
const item = group[name];
const [,type] = item;
const value = this.values[path];
switch (type) {
case 'number': return Number(value);
case 'boolean': return value === true || value === 'true';
default: return value;
default: {
console.error({
path, groupName, name,
group, item,
type, value
});
throw new Error('unknown option type');
}
}
}

262
pointer.js
View File

@ -57,6 +57,152 @@ export class Pointer {
});
}
handlePointerDown({x: clientX, y: clientY}) {
// this.clearPointerHistory(POINTER_DOWN_HISTORY_SIZE);
this.updatePointer({x: clientX, y: clientY});
switch (this.sim.getCurrentMode()) {
case MODE_MASS_GENERATION: {
const {x, y} = this.sim.screenToSim(clientX, clientY)
this.sim.system.handlePointerDown({x, y});
break;
}
case MODE_PAN_VIEW: {
this.touchStart = {
x: clientX,
y: clientY,
t: this.sim.rawTime,
viewOrigin: {...this.sim.display.viewOrigin},
};
// Since we've processed this increment, reset
this.touchLatest = {
...this.touchStart,
dx: 0,
dy: 0,
dt: 0,
};
break;
}
case MODE_OBJECT_SELECT: {
this.sim.select.handlePointerDown({x: clientX, y: clientY});
break;
}
}
}
// Handle cursor (mouse or touch) movement
handlePointerMove({x: clientX, y: clientY}) {
// TODO: If e.touches.length > 1, user may be engaging pinch to zoom
this.updatePointer({x: clientX, y: clientY});
switch (this.sim.getCurrentMode()) {
case MODE_MASS_GENERATION: {
const {x, y} = this.sim.screenToSim(clientX, clientY);
this.sim.system.handlePointerMove({x, y});
break;
}
case MODE_PAN_VIEW: {
if (this.touchStart) {
this.touchLatest = {
x: clientX,
y: clientY,
t: this.sim.rawTime,
dx: clientX - this.touchStart.x,
dy: clientY - this.touchStart.y,
dt: this.sim.rawTime - this.touchStart.t,
};
// With fast panning, this calculation happens every move
// With normal panning, this calculation only happens at pointer up
if (this.sim.getOption('compensate.fastPanning')) {
const panning = {...this.latestVelocity};
// Convert pointer velocity to simulation scale.
// Also multiply by -1 because the camera is
// panning opposite to the pointer velocity.
panning.x /= -this.sim.display.scale;
panning.y /= -this.sim.display.scale;
if (this.sim.getOption('compensate.timeScale')) {
panning.x /= this.sim.timeScale;
panning.y /= this.sim.timeScale;
}
// Also add current panning
panning.x += this.sim.panning?.velocity.x ?? 0;
panning.y += this.sim.panning?.velocity.y ?? 0;
this.sim.panning = {
velocity: panning
};
}
}
break;
}
case MODE_OBJECT_SELECT: {
this.sim.select.handlePointerMove({x: clientX, y: clientY});
break;
}
}
}
handlePointerUp({x: clientX, y: clientY}) {
switch (this.sim.getCurrentMode()) {
case MODE_MASS_GENERATION: {
const {x, y} = this.sim.screenToSim(clientX, clientY);
this.sim.system.handlePointerUp({x, y});
break;
}
case MODE_PAN_VIEW: {
// Set panning velocity
if (this.touchStart && this.touchLatest) {
if (this.touchLatest.dt === 0) {
this.sim.panning = undefined;
}
this.touchStart = undefined;
if (this.sim.getOption('compensate.fastPanning')) {
this.sim.panning = undefined;
} else {
const panning = {...this.latestVelocity};
// Convert pointer velocity to simulation scale.
// Also multiply by -1 because the camera is
// panning opposite to the pointer velocity.
panning.x /= -this.sim.display.scale;
panning.y /= -this.sim.display.scale;
if (this.sim.getOption('compensate.timeScale')) {
panning.x /= this.sim.timeScale;
panning.y /= this.sim.timeScale;
}
// Also add current panning
panning.x += this.sim.panning?.velocity.x ?? 0;
panning.y += this.sim.panning?.velocity.y ?? 0;
this.sim.panning = {
velocity: panning
};
}
}
break;
}
case MODE_OBJECT_SELECT: {
this.sim.select.handlePointerUp({x: clientX, y: clientY});
break;
}
}
}
frame() {
// Add another entry for the current pointer position
const {pointerHistory} = this;
if (pointerHistory.length) {
const currentPointer = pointerHistory[pointerHistory.length - 1];
this.updatePointer(currentPointer);
}
}
getPointerVelocity(points = POINTER_HISTORY_SIZE) {
// Average over pointer history
if (this.pointerHistory.length < 2) {
@ -95,120 +241,4 @@ export class Pointer {
...latestPointer?.v
}
}
handlePointerDown({x: clientX, y: clientY}) {
// this.clearPointerHistory(POINTER_DOWN_HISTORY_SIZE);
this.updatePointer({x: clientX, y: clientY});
switch (this.sim.getCurrentMode()) {
case MODE_MASS_GENERATION: {
const {x, y} = this.sim.screenToSim(clientX, clientY)
this.sim.system.handlePointerDown({x, y});
break;
}
case MODE_PAN_VIEW: {
this.touchStart = {
x: clientX,
y: clientY,
t: this.sim.rawTime,
viewOrigin: {...this.sim.display.viewOrigin},
};
// Since we've processed this increment, reset
this.touchLatest = {
...this.touchStart,
dx: 0,
dy: 0,
dt: 0,
};
break;
}
case MODE_OBJECT_SELECT: {
// TODO: Start a selection box
break;
}
}
}
// Handle cursor (mouse or touch) movement
handlePointerMove({x: clientX, y: clientY}) {
// TODO: If e.touches.length > 1, user may be engaging pinch to zoom
this.updatePointer({x: clientX, y: clientY});
switch (this.sim.getCurrentMode()) {
case MODE_MASS_GENERATION: {
const {x, y} = this.sim.screenToSim(clientX, clientY);
this.sim.system.handlePointerMove({x, y});
break;
}
case MODE_PAN_VIEW: {
if (this.touchStart) {
// Event loop should be able to read
this.touchLatest = {
x: clientX,
y: clientY,
t: this.sim.rawTime,
dx: clientX - this.touchStart.x,
dy: clientY - this.touchStart.y,
dt: this.sim.rawTime - this.touchStart.t,
};
}
break;
}
case MODE_OBJECT_SELECT: {
break;
}
}
}
handlePointerUp({x: clientX, y: clientY}) {
switch (this.sim.getCurrentMode()) {
case MODE_MASS_GENERATION: {
const {x, y} = this.sim.screenToSim(clientX, clientY);
this.sim.system.handlePointerUp({x, y});
break;
}
case MODE_PAN_VIEW: {
// Set panning velocity
if (this.touchStart && this.touchLatest) {
if (!this.touchLatest.dt) {
this.sim.panning = undefined;
} else {
const panning = {...this.latestVelocity};
// Convert pointer velocity to simulation scale.
// Also multiply by -1 because the camera is
// panning opposite to the pointer velocity.
panning.x /= -this.sim.display.scale;
panning.y /= -this.sim.display.scale;
if (this.sim.getOption('compensate.timeScale')) {
panning.x /= this.sim.timeScale;
panning.y /= this.sim.timeScale;
}
// Also add current panning
panning.x += this.sim.panning?.velocity.x ?? 0;
panning.y += this.sim.panning?.velocity.y ?? 0;
this.sim.panning = {
velocity: panning
};
}
this.touchStart = undefined;
}
break;
}
case MODE_OBJECT_SELECT: {
break;
}
}
}
frame() {
// Add another entry for the current pointer position
const { pointerHistory } = this;
if (pointerHistory.length) {
const currentPointer = pointerHistory[pointerHistory.length - 1];
this.updatePointer(currentPointer);
}
}
}

33
select.js Normal file
View File

@ -0,0 +1,33 @@
export class Select {
sim = undefined;
box = {
start: undefined,
end: undefined,
};
constructor(sim) {
this.sim = sim;
}
handlePointerDown({x: clientX, y: clientY}) {
this.box.start = this.sim.screenToSim(clientX, clientY);
}
handlePointerMove({x: clientX, y: clientY}) {
this.box.end = this.sim.screenToSim(clientX, clientY);
}
handlePointerUp() {
console.log('selection box', {...this.box});
this.box = {
start: undefined,
end: undefined,
};
}
frame() {
if (!this.box.start) return;
this.sim.display.drawBox(this.box)
}
}

4
sim-options.js
View File

@ -12,11 +12,9 @@ export const simOptions = {
accelerationScale: ['Accel<br>Vec Scale', 'number', 800, {hideUnless: 'display.acceleration'}],
targetFrameRate: ['Frame Rate', 'number', 60],
},
collision: {
merge: ['Merge Masses on Collision', 'boolean', true, {wide: true}],
},
compensate: {
timeScale: ['Time Scale Compensator', 'boolean', false, {wide: true}],
fastPanning: ['Fast Panning', 'boolean', false],
},
param: {
gravity: ['Gravity', 'number', 1],

5
sim-tools.js
View File

@ -1,5 +1,3 @@
import {Overlay} from './overlay.js';
import {Pointer} from './pointer.js';
import {ModeSwitch} from './tool/modes.js';
import {OptionsTool} from './tool/options.js';
import {PlayPause} from './tool/play-pause.js';
@ -21,7 +19,6 @@ export function initializeTools(sim) {
.addTool(new OptionsTool([
'pauseDuring',
'display',
'collision',
'compensate',
])),
params: new Toolbar(sim, 'Params')
@ -44,8 +41,6 @@ export function initializeTools(sim) {
.addToolbar(params)
.addToolbar(debug),
};
sim.overlay = new Overlay(sim);
sim.pointer = new Pointer(sim);
for (const id in sim.toolbars) {
const toolbar = sim.toolbars[id];

18
simulator.js
View File

@ -4,8 +4,11 @@ import {
} from './config.js';
import {Display} from './display.js';
import {System} from './system.js';
import {Overlay} from './overlay.js';
import {Pointer} from './pointer.js';
import {Options} from './options.js';
import {Zoom} from './zoom.js';
import {Select} from './select.js';
import {simOptions} from './sim-options.js';
import {initializeTools} from './sim-tools.js';
@ -25,6 +28,7 @@ export class Sim {
overlay = undefined;
pointer = undefined;
zoom = undefined;
select = undefined;
toolbarGroups = {};
toolbars = {};
@ -45,7 +49,10 @@ export class Sim {
this.options = new Options(this, simOptions);
this.display = new Display(this);
this.system = new System(this);
this.overlay = new Overlay(this);
this.pointer = new Pointer(this);
this.zoom = new Zoom(this);
this.select = new Select(this);
initializeTools(this);
@ -78,6 +85,7 @@ export class Sim {
this.zoom.frame();
this.pointer.frame();
this.display.frame(elapsedTime);
this.select.frame();
this.system.frame(elapsedTime);
this.overlay.frame();
for (const group in this.toolbarGroups) {
@ -96,7 +104,7 @@ export class Sim {
let duration = t - oldest;
const count = rfs.length + 1;
const frameRate = 1000 * count / duration;
const targetFrameRate = parseInt(this.getOption('display.targetFrameRate'));
const targetFrameRate = this.getOption('display.targetFrameRate');
if (frameRate > targetFrameRate + 1) {
return true;
}
@ -122,10 +130,18 @@ export class Sim {
play() {
this.playing = true;
if (this.panning?.paused) {
this.panning.paused = false;
}
}
pause() {
this.playing = false;
if (this.panning?.velocity) {
this.panning.paused = true;
}
}
getScaleDisplay() {

382
system.js
View File

@ -6,30 +6,208 @@ export class System {
creatingObject = undefined;
selectedObject = undefined;
selectObjectStart = undefined;
paused = false;
panVelocityPaused = undefined;
paused = false;
constructor(sim) {
this.sim = sim;
}
pause() {
if (this.sim.playing) {
this.sim.playing = false;
this.paused = true;
handlePointerDown({x, y}) {
// If pointer is touching an object, select the object
const touchingObject = this.objectAtLocation(x, y);
if (touchingObject !== undefined) {
this.selectObject(touchingObject, {x, y});
} else {
// Otherwise, create a new object
this.createObject(x, y);
}
}
handlePointerUp() {
const obj = this.getSelectedOrCreating();
if (obj === undefined) return;
this.doneCreatingObject();
this.deselect();
// Convert pointer velocity to simulation scale
const pointer = {...this.sim.pointer.latestVelocity};
obj.velocity.x = pointer.x / this.sim.display.scale;
obj.velocity.y = pointer.y / this.sim.display.scale;
// Including time scale - if time is slow, our motion is relatively faster
if (this.sim.getOption('compensate.timeScale')) {
obj.velocity.x /= this.sim.timeScale;
obj.velocity.y /= this.sim.timeScale;
}
if (this.sim.panning?.velocity) {
this.sim.panning.paused = true;
obj.velocity.x += this.sim.panning.velocity.x;
obj.velocity.y += this.sim.panning.velocity.y;
}
}
handlePointerMove({x, y}) {
// If the cursor moves while creating an object, or while an object is selected,
// update the position using the pointer motion but the velocity using the pointer velocity
const obj = this.getSelectedOrCreating();
if (obj === undefined) return;
const start = this.selectedObjectStart;
obj.position.x = start.x + (x - start.pointer.x);
obj.position.y = start.y + (y - start.pointer.y);
obj.velocity.x = 0;
obj.velocity.y = 0;
}
// elapsedTime is given in milliseconds
frame(elapsedTime) {
// If we're creating an object, increment its mass
// with the mass creation rate accelerating over time
// Scaling this parameter because of millisecond conversion
if (this.creatingObject !== undefined) {
const obj = this.objects[this.creatingObject];
let massCreationRate = this.sim.getOption('param.massCreationRate');
massCreationRate /= this.sim.display.scale;
// Keep consistent time scale
if (this.sim.getOption('compensate.timeScale')) {
massCreationRate /= this.sim.timeScale;
}
obj.mass += massCreationRate * elapsedTime;
}
// Calculate forces due to gravity.
this.computeForces();
if (this.sim.playing) {
// Predict positions (Velocity verlet method)
this.forEachObject(obj => {
obj.currentAcceleration = {...obj.acceleration};
// If this object is being created/selected, clamp its position
if (obj.id === this.getSelectedOrCreating()?.id) {
return;
}
obj.position.x += elapsedTime *
(obj.velocity.x + 1 / 2 * obj.currentAcceleration.x * elapsedTime);
obj.position.y += elapsedTime *
(obj.velocity.y + 1 / 2 * obj.currentAcceleration.y * elapsedTime);
});
// Collisions
this.forEachObject((A, i) => {
this.forEachObject((B, j) => {
const dx = (B.position.x - A.position.x);
const dy = (B.position.y - A.position.y);
const dSquared = dx ** 2 + dy ** 2;
const d = Math.sqrt(dSquared);
if (d < A.radius + B.radius) {
let S, T;
// Merge the older into the newer, in order to provide mass creation rate continuity
if (A.age > B.age) {
// A merges into B; B survives
S = B;
T = A;
// If A was selected or being created, select S instead
if (this.creatingObject === i) this.creatingObject = j;
if (this.selectedObject === i) this.selectedObject = j;
} else {
// B merges into A; A survives
S = A;
T = B;
// If B was selected or being created, select S instead
if (this.creatingObject === j) this.creatingObject = i;
if (this.selectedObject === j) this.selectedObject = i;
}
// Merge T into S:
// Set position = center of mass
// Set velocity = total momentum / total mass
// Combine forces
// Sdd masses
// Sverage color
S.position.x = (S.position.x * S.mass + T.position.x * T.mass) / (S.mass + T.mass);
S.position.y = (S.position.y * S.mass + T.position.y * T.mass) / (S.mass + T.mass);
S.velocity.x = (S.velocity.x * S.mass + T.velocity.x * T.mass) / (S.mass + T.mass);
S.velocity.y = (S.velocity.y * S.mass + T.velocity.y * T.mass) / (S.mass + T.mass);
S.forces.push(...T.forces);
S.mass += T.mass;
S.color = {
r: (S.mass * S.color.r + T.mass * T.color.r) / (S.mass + T.mass),
g: (S.mass * S.color.g + T.mass * T.color.g) / (S.mass + T.mass),
b: (S.mass * S.color.b + T.mass * T.color.b) / (S.mass + T.mass),
};
T.alive = false;
T.forces = [];
}
}, {alive: true, startWith: i + 1});
});
// Recompute forces
this.computeForces();
// Predict velocities
this.forEachObject(obj => {
const acceleration = {...obj.acceleration};
obj.acceleration = {
x: (obj.currentAcceleration.x + acceleration.x) / 2,
y: (obj.currentAcceleration.y + acceleration.y) / 2,
};
obj.velocity.x += obj.acceleration.x * elapsedTime;
obj.velocity.y += obj.acceleration.y * elapsedTime;
// Append to object history
obj.history.push({position: {...obj.position}});
// TODO: store object color changes in history
// Enforce object history length
while (obj.history.length > OBJECT_HISTORY_SIZE) {
obj.history.shift();
}
});
}
// Display objects info
// First clear info from previous frame
this.forEachObject((_obj, i) => {
delete this.sim.info[`Object ${i}`];
}, {alive: null});
if (this.sim.getOption('debug.objectsInfo')) {
const aliveOnly = this.sim.getOption('debug.aliveObjects');
this.forEachObject((obj, i) => {
const speed = Math.pow(obj.velocity.x ** 2 + obj.velocity.y ** 2, 1 / 2);
const accel = Math.pow(obj.acceleration.x ** 2 + obj.acceleration.y ** 2, 1 / 2);
// Invert y so that the angle is counterclockwise from x-axis
const direction = Math.atan2(-obj.velocity.y, obj.velocity.x) * 180 / Math.PI;
const accelDir = Math.atan2(-obj.acceleration.y, obj.acceleration.x) * 180 / Math.PI;
const {r, g, b} = obj.color;
this.sim.info[`Object ${i}`] = [
`<span style="background-color: rgb(${r},${g},${b});">&nbsp;&nbsp;</span>`,
`${obj.position.x.toPrecision(4)}, `,
`${obj.position.y.toPrecision(4)}, `,
`${obj.mass.toPrecision(4)} kg, `,
`${speed.toPrecision(2)} m/s, ${direction.toPrecision(2)}°`,
`${accel.toPrecision(2)} m/s<sup>2</sup>, ${accelDir.toPrecision(2)}°`,
`Alive: ${obj.alive}`,
];
}, {alive: aliveOnly || null});
}
// Render the objects
this.drawObjects();
}
pause() {
this.sim.pause();
this.paused = true;
}
resume() {
if (this.paused) {
this.sim.playing = true;
this.paused = false;
if (this.sim.panning?.paused) {
this.sim.panning.paused = false;
}
this.sim.play();
}
}
@ -138,52 +316,6 @@ export class System {
return idx;
}
handlePointerDown({x, y}) {
// If pointer is touching an object, select the object
const touchingObject = this.objectAtLocation(x, y);
if (touchingObject !== undefined) {
this.selectObject(touchingObject, {x, y});
} else {
// Otherwise, create a new object
this.createObject(x, y);
}
}
handlePointerUp() {
const obj = this.getSelectedOrCreating();
if (obj === undefined) return;
this.doneCreatingObject();
this.deselect();
// Convert pointer velocity to simulation scale
const pointer = {...this.sim.pointer.latestVelocity};
obj.velocity.x = pointer.x / this.sim.display.scale;
obj.velocity.y = pointer.y / this.sim.display.scale;
// Including time scale - if time is slow, our motion is relatively faster
if (this.sim.getOption('compensate.timeScale')) {
obj.velocity.x /= this.sim.timeScale;
obj.velocity.y /= this.sim.timeScale;
}
if (this.sim.panning?.velocity) {
obj.velocity.x += this.sim.panning.velocity.x;
obj.velocity.y += this.sim.panning.velocity.y;
}
}
handlePointerMove({x, y}) {
// If the cursor moves while creating an object, or while an object is selected,
// update the position using the pointer motion but the velocity using the pointer velocity
const obj = this.getSelectedOrCreating();
if (obj === undefined) return;
const start = this.selectedObjectStart;
obj.position.x = start.x + (x - start.pointer.x);
obj.position.y = start.y + (y - start.pointer.y);
obj.velocity.x = 0;
obj.velocity.y = 0;
}
// cb: (obj, idx) => {}
forEachObject(cb, {alive, startWith} = {}) {
if (alive === undefined) alive = true;
@ -237,143 +369,6 @@ export class System {
});
}
// elapsedTime is given in milliseconds
frame(elapsedTime) {
// If we're creating an object, increment its mass
// with the mass creation rate accelerating over time
// Scaling this parameter because of millisecond conversion
if (this.creatingObject !== undefined) {
const obj = this.objects[this.creatingObject];
let massCreationRate = this.sim.getOption('param.massCreationRate');
massCreationRate /= this.sim.display.scale;
// Keep consistent time scale
if (this.sim.getOption('compensate.timeScale')) {
massCreationRate /= this.sim.timeScale;
}
obj.mass += massCreationRate * elapsedTime;
}
// Calculate forces due to gravity.
this.computeForces();
if (this.sim.playing) {
// Predict positions (Velocity verlet method)
this.forEachObject(obj => {
obj.currentAcceleration = {...obj.acceleration};
obj.position.x += elapsedTime *
(obj.velocity.x + 1 / 2 * obj.currentAcceleration.x * elapsedTime);
obj.position.y += elapsedTime *
(obj.velocity.y + 1 / 2 * obj.currentAcceleration.y * elapsedTime);
});
// Collisions
if (this.sim.getOption('collision.merge')) {
this.forEachObject((A, i) => {
this.forEachObject((B, j) => {
const dx = (B.position.x - A.position.x);
const dy = (B.position.y - A.position.y);
const dSquared = dx ** 2 + dy ** 2;
const d = Math.sqrt(dSquared);
if (d < A.radius + B.radius) {
let S, T;
// Merge the older into the newer, in order to provide mass creation rate continuity
if (A.age > B.age) {
// A merges into B; B survives
S = B;
T = A;
// If A was selected or being created, select S instead
if (this.creatingObject === i) this.creatingObject = j;
if (this.selectedObject === i) this.selectedObject = j;
} else {
// B merges into A; A survives
S = A;
T = B;
// If B was selected or being created, select S instead
if (this.creatingObject === j) this.creatingObject = i;
if (this.selectedObject === j) this.selectedObject = i;
}
// Merge T into S:
// Set position = center of mass
// Set velocity = total momentum / total mass
// Combine forces
// Sdd masses
// Sverage color
S.position.x = (S.position.x * S.mass + T.position.x * T.mass) / (S.mass + T.mass);
S.position.y = (S.position.y * S.mass + T.position.y * T.mass) / (S.mass + T.mass);
S.velocity.x = (S.velocity.x * S.mass + T.velocity.x * T.mass) / (S.mass + T.mass);
S.velocity.y = (S.velocity.y * S.mass + T.velocity.y * T.mass) / (S.mass + T.mass);
S.forces.push(...T.forces);
S.mass += T.mass;
S.color = {
r: (S.mass * S.color.r + T.mass * T.color.r) / (S.mass + T.mass),
g: (S.mass * S.color.g + T.mass * T.color.g) / (S.mass + T.mass),
b: (S.mass * S.color.b + T.mass * T.color.b) / (S.mass + T.mass),
};
T.alive = false;
T.forces = [];
}
}, {alive: true, startWith: i + 1});
});
}
// Recompute forces
this.computeForces();
// Predict velocities
this.forEachObject(obj => {
const acceleration = {...obj.acceleration};
obj.acceleration = {
x: (obj.currentAcceleration.x + acceleration.x) / 2,
y: (obj.currentAcceleration.y + acceleration.y) / 2,
};
obj.velocity.x += obj.acceleration.x * elapsedTime;
obj.velocity.y += obj.acceleration.y * elapsedTime;
// Append to object history
obj.history.push({position: {...obj.position}});
// TODO: store object color changes in history
// Enforce object history length
while (obj.history.length > OBJECT_HISTORY_SIZE) {
obj.history.shift();
}
});
}
// Display objects info
// First clear info from previous frame
this.forEachObject((_obj, i) => {
delete this.sim.info[`Object ${i}`];
}, {alive: null});
if (this.sim.getOption('debug.objectsInfo')) {
const aliveOnly = this.sim.getOption('debug.aliveObjects');
this.forEachObject((obj, i) => {
const speed = Math.pow(obj.velocity.x ** 2 + obj.velocity.y ** 2, 1 / 2);
const accel = Math.pow(obj.acceleration.x ** 2 + obj.acceleration.y ** 2, 1 / 2);
// Invert y so that the angle is counterclockwise from x-axis
const direction = Math.atan2(-obj.velocity.y, obj.velocity.x) * 180 / Math.PI;
const accelDir = Math.atan2(-obj.acceleration.y, obj.acceleration.x) * 180 / Math.PI;
const {r, g, b} = obj.color;
this.sim.info[`Object ${i}`] = [
`<span style="background-color: rgb(${r},${g},${b});">&nbsp;&nbsp;</span>`,
`${obj.position.x.toPrecision(4)}, `,
`${obj.position.y.toPrecision(4)}, `,
`${obj.mass.toPrecision(4)} kg, `,
`${speed.toPrecision(2)} m/s, ${direction.toPrecision(2)}°`,
`${accel.toPrecision(2)} m/s<sup>2</sup>, ${accelDir.toPrecision(2)}°`,
`Alive: ${obj.alive}`,
];
}, {alive: aliveOnly || null});
}
// Render the objects
this.drawObjects();
}
computeSystemCenter() {
// Determine center of mass
const {totalMass, count, totalMassLocation} =
@ -423,4 +418,5 @@ export class System {
return acc + obj.mass * s / d;
}, 0);
}
}

4
tool/options.js
View File

@ -19,8 +19,8 @@ export class OptionsTool extends Tool {
super.setContainer(container);
for (const sectionName of this.sections) {
const option = this.sim.options.getSection(sectionName);
const child = this.visitItem(option);
this.div.appendChild(child);
const item = this.visitItem(option);
this.div.appendChild(item);
}
}

3
zoom.js
View File

@ -48,7 +48,8 @@ export class Zoom {
// if (this.sim.playing && velocity) {
if (velocity) {
this.sim.panning = {
velocity: { ...velocity }
velocity: { ...velocity },
paused: !this.sim.playing,
};
}