no extra ssh on commit

This reverts commit 403ce4b6830bf3943c03bc772b0a0d9648b270cb.

Readme.md

@@ -8,7 +8,7 @@ Uses `npm` for `eslint`.
 TODO
 ----
 
-[ ] Numeric Option Type
+[x] Numeric Option Type
 [ ] Time Indicator
 [ ] Selection Box
 [ ] Object List

objects.js

@@ -2,7 +2,6 @@ import { MassObject } from './object.js';
 import { 
   MASS_CREATION_RATE, 
   DISPLAY_OBJECTS_INFO,
-  GRAVITATIONAL_CONSTANT,
   ZOOM_TO_FIT_PADDING,
 } from './config.js';
 
@@ -169,6 +168,7 @@ export class Objects {
   }
 
   computeForces() {
+    const gravity = this.sim.getOption('param.gravity');
     if (this.objects.length < 2) return;
     this.forEachObject(obj => {
       obj.forces = [];
@@ -179,7 +179,7 @@ export class Objects {
         const dy = (B.position.y - A.position.y);
         const dSquared = dx ** 2 + dy ** 2;
         const d = Math.sqrt(dSquared);
-        const F = GRAVITATIONAL_CONSTANT * A.mass * B.mass / dSquared;
+        const F = gravity * A.mass * B.mass / dSquared;
         const Fx = F * dx / d;
         const Fy = F * dy / d;
         A.forces.push({ x: Fx, y: Fy });

style.css

@@ -47,7 +47,7 @@ div.lhg-toolbar div.lhg-tool {
   border-color: #282;
 }
 
-div.lhg-tool button {
+div.lhg-tool button, div.lhg-tool input {
   font-family: monospace;
   font-size: 10pt;
   width: 6em;
@@ -66,6 +66,10 @@ div.lhg-tool button {
   margin-right: 0;
 }
 
+div.lhg-tool input {
+  width: 5EM;
+}
+
 div.lhg-tool button:hover {
   background-color: #444;
 }
@@ -86,16 +90,24 @@ div.lhg-toolbar-header > * {
   display: inline-block;
 }
 
-div.lhg-tool button.lhg-tool-info {
+div.lhg-tool .lhg-tool-info {
   background-color: #111;
   border-color: #282;
   border-width: 0px;
 }
 
-div.lhg-tool button.lhg-wide {
+div.lhg-tool .lhg-wide {
   width: 12em;
 }
 
+div.lhg-tool input.lhg-wide {
+  width: 11em;
+}
+
+div.lhg-tool .lhg-tool-info.lhg-wide {
+  width: 11em;
+}
+
 div.lhg-tool > div {
   /* border: 2px red solid; */
 }

tool/options.js

@@ -2,10 +2,12 @@
 import {
   DISPLAY_ACCELERATION_VECTORS,
   DISPLAY_VELOCITY_VECTORS,
+  GRAVITATIONAL_CONSTANT,
   MERGE_ON_COLLIDE,
   PATH_TRACES_DASHED,
   PAUSE_DURING_CREATION,
   PAUSE_DURING_SELECTION,
+  TOOL_INFO_CLASSNAME,
   WIDE_CLASSNAME,
 } from '../config.js';
 import {Tool} from '../tool.js';
@@ -30,6 +32,11 @@ export class Options extends Tool {
     items: [
       {type: 'boolean', name: 'merge', title: 'Merge Masses', default: MERGE_ON_COLLIDE, wide: true},
     ]
+  }, {
+    type: 'group', name: 'param', title: 'Parameters',
+    items: [
+      {type: 'number', name: 'gravity', title: 'Gravity', default: GRAVITATIONAL_CONSTANT},
+    ]
   }];
 
   values = {};
@@ -62,6 +69,32 @@ export class Options extends Tool {
         });
         return button;
       }
+      case 'number': {
+        const div = document.createElement('div');
+        const title = document.createElement('button');
+        const input = document.createElement('input');
+        const maxLength = item.maxLength || 8;
+        div.appendChild(title);
+        div.appendChild(input);
+        div.classList.add(WIDE_CLASSNAME);
+        title.classList.add(TOOL_INFO_CLASSNAME);
+        if (item.wide) {
+          // title.classList.add(WIDE_CLASSNAME);
+          input.classList.add(WIDE_CLASSNAME);
+        }
+        title.innerHTML = item.title;
+        input.value = item.default;
+        this.setOption(path, item.default);
+
+        input.addEventListener('input', () => {
+          input.value = input.value.slice(0, maxLength);
+        });
+
+        input.addEventListener('change', () => {
+          this.setOption(path, input.value);
+        });
+        return div;
+      }
       default:
         throw new Error('unknown option type');
     }

tool/zoom.js

@@ -22,19 +22,23 @@ export class Zoom extends Tool {
     const zoomOut = document.createElement('button');
     const zoomIn = document.createElement('button');
     const zoomAll = document.createElement('button');
+    const zeroVelocity = document.createElement('button');
 
     this.div.appendChild(currentScale);
     this.div.appendChild(zoomOut);
     this.div.appendChild(zoomIn);
     this.div.appendChild(zoomAll);
+    this.div.appendChild(zeroVelocity);
 
     zoomAll.classList.add(WIDE_CLASSNAME);
+    zeroVelocity.classList.add(WIDE_CLASSNAME);
     currentScale.classList.add(WIDE_CLASSNAME);
     currentScale.classList.add(TOOL_INFO_CLASSNAME);
 
     zoomOut.innerHTML = 'Zoom<br>Out';
     zoomIn.innerHTML = 'Zoom<br>In';
     zoomAll.innerHTML = 'Zoom to Fit';
+    zeroVelocity.innerHTML = 'Zero Net Velocity';
     currentScale.innerHTML = this.displayScaleText;
 
     this.sim.onZoom(() => {
@@ -84,5 +88,30 @@ export class Zoom extends Tool {
       };
       this.sim.scheduleZoom({x, y}, factor, netVelocity)
     });
+
+    zeroVelocity.addEventListener('click', () => {
+      // Determine average momentum
+      const netMomentum = {x: 0, y: 0};
+      let totalMass = 0;
+      let count = 0;
+      this.sim.objects.forEachObject(obj => {
+        count++;
+        netMomentum.x += obj.mass * obj.velocity.x;
+        netMomentum.y += obj.mass * obj.velocity.y;
+        totalMass += obj.mass;
+      });
+      if (!count) {
+        return;
+      }
+      const netVelocity = {
+        x: netMomentum.x / totalMass,
+        y: netMomentum.y / totalMass,
+      };
+      // Apply offset to all object velocities
+      this.sim.objects.forEachObject(obj => {
+        obj.velocity.x -= netVelocity.x;
+        obj.velocity.y -= netVelocity.y;
+      });
+    });
   }
 }