Physics System Test

Run 5 test suites covering gravity, static body verification, PhysicsBody state, system/component registration, and stability.

Configuration:

• EXAMPLE_DIR: $IWSDK_REPO_ROOT/examples/physics

Tool calls: every tool call is npx @iwsdk/cli <subcommand> [--input-json '<JSON>'] [--timeout <ms>], run from inside the example workspace (cwd $EXAMPLE_DIR). The CLI auto-discovers the IWSDK app root from cwd, so no path tricks are required. Run npx @iwsdk/cli mcp inspect from the example to discover available tools and their CLI subcommands.

• <JSON> is a JSON object string. Omit --input-json if no arguments are needed.
• Output is JSON on stdout: {ok, workspaceRoot, operation, result}. Parse it to check assertions.
• Use --timeout 20000 for operations that may take longer (reload, xr enter, screenshot).

IMPORTANT: Run each Bash command one at a time. Parse the JSON output and verify assertions before moving to the next command. Do NOT chain multiple CLI commands together.

IMPORTANT: When the instructions say "wait N seconds", use sleep N as a separate Bash command.

Step 1: Install Dependencies

cd $IWSDK_REPO_ROOT/examples/physics && npm run fresh:install

Wait for this to complete before proceeding.

Step 2: Start Dev Server

Start the dev server as a background task using the Bash tool's run_in_background: true parameter:

cd $IWSDK_REPO_ROOT/examples/physics && npm run dev

IMPORTANT: This command MUST be run with run_in_background: true on the Bash tool — do NOT append & to the command itself.

Once the background task is launched, poll the output for Vite's ready message (up to 60s). You can also run npx @iwsdk/cli dev status from the example directory until state.running becomes true. You do not need to extract or manage the port yourself; subsequent commands resolve the active runtime through the CLI automatically.

If the server fails to start within 60 seconds, report FAIL for all suites and skip to Step 5.

Step 3: Verify Connectivity

npx @iwsdk/cli ecs systems 2>/dev/null

This must return JSON with a list of systems. If it fails:

1. Check the dev server output for errors
2. Try killing and restarting the server (Step 2)
3. If it still fails, report FAIL for all suites and skip to Step 5

Step 4: Run Test Suites

Pre-test Setup

Run these commands in order:

1. npx @iwsdk/cli browser reload --timeout 20000 2>/dev/null Then: sleep 3
2. npx @iwsdk/cli xr enter --timeout 20000 2>/dev/null Then: sleep 2
3. npx @iwsdk/cli browser logs --input-json '{"count":20,"level":["error","warn"]}' 2>/dev/null Assert: No error-level logs.

Verify Physics Setup

Find all physics bodies:

npx @iwsdk/cli ecs find --input-json '{"withComponents":["PhysicsBody"]}' 2>/dev/null

Assert: At least 1 entity.

For each entity found, query to identify dynamic vs static:

npx @iwsdk/cli ecs query --input-json '{"entityIndex":<N>,"components":["PhysicsBody"]}' 2>/dev/null

Check state field: "DYNAMIC" or "STATIC".

Save the entity named Dynamic Sphere as <sphere> and any static entity as <floor>. The example contains multiple dynamic bodies with intentionally different damping and gravity settings, so do not select an arbitrary one.

Verify PhysicsSystem:

npx @iwsdk/cli ecs systems 2>/dev/null

Assert: PhysicsSystem at priority -2, physicsEntities count >= 1.

Suite 1: Gravity — Dynamic Body Falls

Test 1.1: Verify Dynamic Entity Exists

npx @iwsdk/cli ecs query --input-json '{"entityIndex":<sphere>,"components":["PhysicsBody","Transform"]}' 2>/dev/null

Assert:

• state: "DYNAMIC"
• _engineBody: > 0 (Havok body created)
• gravityFactor: 1

Note: By the time you query, the sphere may have already fallen and come to rest.

Test 1.2: Deterministic Gravity Test

Reset the sphere position, then use pause/step to observe fall:

npx @iwsdk/cli ecs pause 2>/dev/null

npx @iwsdk/cli ecs set-component --input-json '{"entityIndex":<sphere>,"componentId":"Transform","field":"position","value":"[0, 3, -1.5]"}' 2>/dev/null

npx @iwsdk/cli ecs snapshot --input-json '{"label":"before-fall"}' 2>/dev/null

npx @iwsdk/cli ecs step --input-json '{"count":50}' 2>/dev/null

npx @iwsdk/cli ecs snapshot --input-json '{"label":"after-fall"}' 2>/dev/null

npx @iwsdk/cli ecs diff --input-json '{"from":"before-fall","to":"after-fall"}' 2>/dev/null

Assert:

• Sphere's Transform.position[1] (Y) decreased from 3.0
• Only the dynamic sphere entity changed significantly

npx @iwsdk/cli ecs resume 2>/dev/null

Suite 2: Static Body Doesn't Move

Test 2.1: Static Floor Stays Put

If a static entity was found during setup:

npx @iwsdk/cli ecs query --input-json '{"entityIndex":<floor>,"components":["PhysicsBody","Transform"]}' 2>/dev/null

Assert:

• state: "STATIC"
• _linearVelocity: [0, 0, 0]
• _angularVelocity: [0, 0, 0]

Note: If no separate static PhysicsBody entity exists (environment geometry may not use PhysicsBody), skip this suite and report SKIP.

Suite 3: PhysicsBody State Values

Test 3.1: Inspect Dynamic Body Fields

npx @iwsdk/cli ecs query --input-json '{"entityIndex":<sphere>,"components":["PhysicsBody"]}' 2>/dev/null

Assert:

• state: "DYNAMIC"
• linearDamping: 2
• angularDamping: 2
• gravityFactor: 1
• _engineBody: > 0 (non-zero Havok handle)

Suite 4: System & Component Registration

Test 4.1: PhysicsSystem at Correct Priority

npx @iwsdk/cli ecs systems 2>/dev/null

Assert:

• PhysicsSystem at priority -2
• Config keys: gravity, useWorker, updateFrequency, interpolation

Test 4.2: Physics Components Registered

npx @iwsdk/cli ecs components 2>/dev/null

Assert:

• PhysicsBody: state (Enum), linearDamping (Float32), angularDamping (Float32), gravityFactor (Float32), _linearVelocity (Vec3), _angularVelocity (Vec3), _engineBody (Float64)
• PhysicsShape: shape (Enum), dimensions (Vec3), density (Float32), restitution (Float32), friction (Float32), _engineShape (Float64)
• PhysicsManipulation: force (Vec3), linearVelocity (Vec3), angularVelocity (Vec3)

Suite 5: Stability

npx @iwsdk/cli browser logs --input-json '{"count":30,"level":["error","warn"]}' 2>/dev/null

Assert: No application-level errors or warnings. Pre-existing 404 resource errors from page load are acceptable.

Step 5: Cleanup & Results

Kill the dev server:

cd $IWSDK_REPO_ROOT/examples/physics && npx @iwsdk/cli dev down

Output a summary table:

| Suite                     | Result         |
|---------------------------|----------------|
| 1. Gravity                | PASS/FAIL      |
| 2. Static Body            | PASS/FAIL/SKIP |
| 3. PhysicsBody State      | PASS/FAIL      |
| 4. System/Component Reg.  | PASS/FAIL      |
| 5. Stability              | PASS/FAIL      |

If any suite fails, include which assertion failed and actual vs expected values.

Recovery

If at any point a transient error occurs (server crash, WebSocket timeout, connection refused, etc.) that is NOT caused by a source code bug:

1. Stop the dev server: cd $IWSDK_REPO_ROOT/examples/physics && npx @iwsdk/cli dev down
2. Restart: re-run Step 2 to start a fresh dev server
3. Re-run the Pre-test Setup (reload, accept session)
4. Retry the failed suite

Only give up after one retry attempt per suite. If the same suite fails twice, mark it FAIL and continue to the next suite.

Known Issues & Workarounds

Sphere falls immediately

The dynamic sphere starts falling as soon as the Havok body is created. Use npx @iwsdk/cli ecs pause immediately after reload to catch it, or use the deterministic reset approach.

PhysicsManipulation is one-shot

PhysicsManipulation is automatically removed after forces are applied in a single frame. You cannot query it after processing.

Setting Transform doesn't always override physics

While PhysicsSystem is running, it may overwrite your position on the next frame. Use npx @iwsdk/cli ecs pause before modifying positions.

Havok WASM initialization is async

Bodies may not be created on the first frame. The _engineBody field transitions from 0 to non-zero once Havok processes the entity.

Entity indices change on reload

Never cache entity indices across page reloads. Always re-discover via npx @iwsdk/cli ecs find.