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Merged
mattqdev merged 7 commits into from
Mar 6, 2026
Merged

Parabolic motion #223

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ef336aa
fixed ground collision and ball jumping at h0=0
txgh25 Mar 6, 2026
1186687
Clean up debug logs in ParabolicMotion.jsx
txgh25 Mar 6, 2026
6d0f5d4
Ran prettier --write
txgh25 Mar 6, 2026
6bd0c80
Fixed prettier formatting
txgh25 Mar 6, 2026
9be12a5
formatting
txgh25 Mar 6, 2026
83dd255
Merge branch 'main' of https://github.com/txgh25/physicshub.github.io
txgh25 Mar 6, 2026
eb87837
missed file
txgh25 Mar 6, 2026
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90 changes: 58 additions & 32 deletions CLAUDE_REPORT.md
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Original file line number Diff line number Diff line change
Expand Up @@ -11,12 +11,12 @@

The PhysicsHub codebase is a well-structured interactive physics simulation platform. The core architecture (centralized `PhysicsBody`, `ForceCalculator`, `ForceRenderer`, `DragController`) is thoughtfully designed. However, the audit identified **23 confirmed bugs and quality issues** across 4 severity tiers.

| Severity | Count | Key Area |
|---|---|---|
| 🔴 Critical | 3 | Physics correctness, broken physics engine |
| 🟠 High | 5 | Integration bugs, null crashes, broken reset |
| 🟡 Medium | 9 | Code quality, dead code, unit errors |
| 🟢 Low | 6 | Performance, UX, naming |
| Severity | Count | Key Area |
| ----------- | ----- | -------------------------------------------- |
| 🔴 Critical | 3 | Physics correctness, broken physics engine |
| 🟠 High | 5 | Integration bugs, null crashes, broken reset |
| 🟡 Medium | 9 | Code quality, dead code, unit errors |
| 🟢 Low | 6 | Performance, UX, naming |

---

Expand Down Expand Up @@ -50,11 +50,13 @@ All physics runs in **Y-UP** (standard physics: y increases upward). Rendering c
The file contains the full source of `Spring.ts` (TypeScript `interface` declarations, class definition, methods) appended directly after `export default PhysicsBody`. This creates a `.js` file with TypeScript syntax, which will crash in any environment that does not transpile `.js` files as TypeScript. Two separate modules should not share one file.

**Fix:**

```js
// PhysicsBody.js — everything after this line must be removed:
export default PhysicsBody;
// ← file ends here. Spring.ts content below must be deleted.
```

Ensure `Spring.ts` is the sole location for the Spring class.

---
Expand All @@ -68,13 +70,24 @@ Ensure `Spring.ts` is the sole location for the Spring class.

```js
// SpringConnection.jsx — BUGGY direct call:
renderer.drawVector(p, screenPos.x, screenPos.y,
gravityForce.x, gravityForce.y, // gravityForce.y = -mass*g → draws UP on screen
"#ef4444", "Weight");
renderer.drawVector(
p,
screenPos.x,
screenPos.y,
gravityForce.x,
gravityForce.y, // gravityForce.y = -mass*g → draws UP on screen
"#ef4444",
"Weight"
);

// FIX — use the dedicated helper which handles direction correctly:
renderer.drawWeight(p, screenPos.x, screenPos.y,
bodyRef.current.params.mass, inputsRef.current.gravity);
renderer.drawWeight(
p,
screenPos.x,
screenPos.y,
bodyRef.current.params.mass,
inputsRef.current.gravity
);
```

---
Expand All @@ -87,14 +100,15 @@ renderer.drawWeight(p, screenPos.x, screenPos.y,
```js
const scale = 0; //getTimeScale(); ← DEBUG LEFTOVER, never removed
if (!isPaused()) {
accumulator += dt * Math.max(0, scale); // accumulator always stays 0
accumulator += dt * Math.max(0, scale); // accumulator always stays 0
}
// worldRef.current.step() is never called → Planck.js body never moves
```

The `getTimeScale()` call was commented out. The physics body is created and displayed but completely frozen regardless of user interaction.

**Fix:**

```js
import { getTimeScale } from "../app/(core)/constants/Time.js";
// ...
Expand All @@ -115,6 +129,7 @@ const scale = getTimeScale(); // restore this line
The method signature `stepAlongPlane(dt, netForceParallel)` ignores the `angleRad` argument passed by the caller. The 2D `state.velocity` is set as `(velAlongPlane, 0)` instead of being projected onto the plane's actual direction. This makes `state.velocity` incorrect for energy calculations.

**Fix:**

```js
stepAlongPlane(dt, netForceParallel, angleRad = 0) {
if (dt <= 0) return;
Expand All @@ -140,12 +155,14 @@ stepAlongPlane(dt, netForceParallel, angleRad = 0) {

```js
// BUGGY — measures angle from (0,0), not from the anchor pivot
const angle = (Math.atan2(bodyState.position.x, -bodyState.position.y) * 180) / Math.PI;
const angle =
(Math.atan2(bodyState.position.x, -bodyState.position.y) * 180) / Math.PI;
```

The anchor is at `(w/2 meters, h*0.2 meters)` in physics space — not at origin. This formula produces completely wrong angle values. The `PendulumBody.getAngle()` method is already correct and should be used instead.

**Fix:** Pass `body.getAngle()` directly into `SimInfoMapper` via the state object:

```js
// In sketch p.draw():
updateSimInfo(p, {
Expand Down Expand Up @@ -192,6 +209,7 @@ potentialEnergy: bodyRef.current.getPotentialEnergy(gravity, toMeters(p.height))
In Y-up coordinates, the ground is at `y = 0`. `toMeters(p.height)` is the **canvas top** in meters (a large positive number). So `PE = mass * g * (position.y - large_number)` is almost always large and negative — incorrect.

**Fix:**

```js
// Ground reference in Y-up space is y = 0 (or ball radius for center-of-mass)
potentialEnergy: bodyRef.current.getPotentialEnergy(gravity, 0),
Expand All @@ -215,6 +233,7 @@ body.applyForce(force);
When the spring is extended (`displacement > 0`), `springForceMag` is negative, which flips the direction vector to point **away** from the anchor. An extended spring should pull the body toward the anchor.

**Fix:**

```ts
public connect(body: PhysicsBody): void {
const toAnchor = p5.Vector.sub(this.anchor, body.state.position);
Expand Down Expand Up @@ -301,6 +320,7 @@ friction = ForceCalculator.kineticFriction(normal, frictionKinetic, vel);
Should use `body.planeState.velAlongPlane` (the scalar velocity along the plane). `state.velocity.x` is only the horizontal projection, underestimating friction when the angle is non-zero.

**Fix:**

```js
const vel = body.planeState?.velAlongPlane ?? body.state.velocity?.x ?? 0;
```
Expand Down Expand Up @@ -340,53 +360,59 @@ The `+` operation draws from absolute screen coordinates (origin = top-left corn
---

### BUG-018 — package.json: engines.node uses exact version instead of range

```json
"engines": { "node": "24.8.0" } // should be ">=24.0.0"
```

### BUG-019 — Config.js: Mars gravity label shows 3.71 m/s² (actual: 3.72 m/s²)

```js
{ value: 0.379 * earthG, label: "Mars (3.71 m/s²)" }
// 0.379 * 9.81 = 3.719 ≈ 3.72, label should read "Mars (3.72 m/s²)"
```

### BUG-020 — VectorsOperations.jsx: "dot" and "cross" case renderers are identical

Both cases draw the exact same three lines. The cross product should show a shaded parallelogram (area = |A×B|), the dot product should show a projection onto A.

### BUG-021 — test.jsx: Collision separation check has inverted sign condition

```js
if (velAlongNormal < 0) continue; // "don't resolve if separating"
// relVel · normal > 0 means separating → should be: if (velAlongNormal > 0) continue
```

### BUG-022 — BallGravity.jsx: isBlowing state set but wind-overlay CSS class likely missing

`setIsBlowing(true/false)` updates state and toggles class `wind-overlay blowing`, but no CSS for this class was found in the uploaded styles. The wind animation has no visual effect.

### BUG-023 — DragController.js: Same file-concatenation artifact as BUG-001

The `DragController.js` file content contains appended source from other files (similar to BUG-001). Each physics module file should contain only its own source.

---

## Priority Fix Order

| # | Bug | File | Effort |
|---|---|---|---|
| 1 | BUG-001, BUG-023 | Separate concatenated files | 30 min |
| 2 | BUG-003 | Restore getTimeScale() | 5 min |
| 3 | BUG-008 | Fix Spring.connect() sign | 15 min |
| 4 | BUG-002 | Fix weight vector direction | 1 hr |
| 5 | BUG-007 | Fix PE reference height | 30 min |
| 6 | BUG-004 | Fix stepAlongPlane 2D projection | 1 hr |
| 7 | BUG-006 | Remove hardcoded reset dimensions | 15 min |
| 8 | BUG-005 | Fix pendulum angle display | 1 hr |
| 9 | BUG-012 | Fix gravity hardcoding in renderer | 30 min |
| 10 | BUG-014 | Fix kinetic friction velocity source | 15 min |
| 11 | BUG-011 | Move SimplePendulum config | 30 min |
| 12 | BUG-021 | Fix collision sign | 5 min |
| 13 | BUG-013 | Add cleanupInstance on unmount | 30 min |
| 14 | BUG-010 | Fix drag label unit | 5 min |
| 15 | BUG-015 | Remove/migrate dead utils | 15 min |
| 16 | All others | Remaining low-priority | ~2 hr |
| # | Bug | File | Effort |
| --- | ---------------- | ------------------------------------ | ------ |
| 1 | BUG-001, BUG-023 | Separate concatenated files | 30 min |
| 2 | BUG-003 | Restore getTimeScale() | 5 min |
| 3 | BUG-008 | Fix Spring.connect() sign | 15 min |
| 4 | BUG-002 | Fix weight vector direction | 1 hr |
| 5 | BUG-007 | Fix PE reference height | 30 min |
| 6 | BUG-004 | Fix stepAlongPlane 2D projection | 1 hr |
| 7 | BUG-006 | Remove hardcoded reset dimensions | 15 min |
| 8 | BUG-005 | Fix pendulum angle display | 1 hr |
| 9 | BUG-012 | Fix gravity hardcoding in renderer | 30 min |
| 10 | BUG-014 | Fix kinetic friction velocity source | 15 min |
| 11 | BUG-011 | Move SimplePendulum config | 30 min |
| 12 | BUG-021 | Fix collision sign | 5 min |
| 13 | BUG-013 | Add cleanupInstance on unmount | 30 min |
| 14 | BUG-010 | Fix drag label unit | 5 min |
| 15 | BUG-015 | Remove/migrate dead utils | 15 min |
| 16 | All others | Remaining low-priority | ~2 hr |

**Estimated total fix time: ~10 hours**

Expand All @@ -406,4 +432,4 @@ The `DragController.js` file content contains appended source from other files (

---

*Report generated by static analysis of repository snapshot `physicshub.github.io-main`.*
_Report generated by static analysis of repository snapshot `physicshub.github.io-main`._
2 changes: 1 addition & 1 deletion package.json
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Original file line number Diff line number Diff line change
Expand Up @@ -67,7 +67,7 @@
"husky": "^9.1.7",
"lint-staged": "^16.2.7",
"nodemon": "^3.1.10",
"prettier": "3.8.0",
"prettier": "^3.8.0",
"puppeteer": "^24.34.0",
"sitemap": "^9.0.1",
"tailwindcss": "^4",
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