// Test locomotion system (slide, snap turn, teleport, jump) against the locomotion example using the iwsdk CLI.
MUST read this skill BEFORE developing VR/MR/browser-first 3D applications using IWSDK (Immersive Web SDK). Covers project scaffolding, headless browser setup, CLI tools, reference system, ECS debugging, XR emulation, verification workflows, deployment, and known issues.
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| name | test-locomotion |
| description | Test locomotion system (slide, snap turn, teleport, jump) against the locomotion example using the iwsdk CLI. |
| argument-hint | [--suite slide|turn|teleport|jump|all] |
Run 6 test suites covering slide movement, snap turn, teleport, jump, system registration, and stability.
Configuration:
$IWSDK_REPO_ROOT/examples/locomotionTool calls: every tool call is npx iwsdk <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 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.{ok, workspaceRoot, operation, result}. Parse it to check assertions.--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.
cd $IWSDK_REPO_ROOT/examples/locomotion && npm run fresh:install
Wait for this to complete before proceeding.
Start the dev server as a background task using the Bash tool's run_in_background: true parameter:
cd $IWSDK_REPO_ROOT/examples/locomotion && 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 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.
npx iwsdk ecs systems 2>/dev/null
This must return JSON with a list of systems. If it fails:
Run these commands in order:
npx iwsdk browser reload --timeout 20000 2>/dev/null
Then: sleep 3
npx iwsdk xr enter --timeout 20000 2>/dev/null
Then: sleep 2
npx iwsdk browser logs --input-json '{"count":20,"level":["error","warn"]}' 2>/dev/null
Assert: No error-level logs.
npx iwsdk ecs find --input-json '{"withComponents":["LocomotionEnvironment"]}' 2>/dev/null
Assert: At least 1 entity. Save as <env>.
npx iwsdk ecs query --input-json '{"entityIndex":<env>,"components":["LocomotionEnvironment"]}' 2>/dev/null
Assert: _initialized = true, _envHandle > 0.
npx iwsdk ecs systems 2>/dev/null
Assert:
| Action | Controller | Input | Tool |
|---|---|---|---|
| Slide forward | Left | Thumbstick Y = -1 | npx iwsdk xr set-gamepad-state axes [{0, 0}, {1, -1}] |
| Slide backward | Left | Thumbstick Y = 1 | npx iwsdk xr set-gamepad-state axes [{0, 0}, {1, 1}] |
| Snap turn right | Right | Thumbstick X = 1 (edge) | npx iwsdk xr set-gamepad-state axes [{0, 1}, {1, 0}] |
| Snap turn left | Right | Thumbstick X = -1 (edge) | npx iwsdk xr set-gamepad-state axes [{0, -1}, {1, 0}] |
| Teleport activate | Right | Thumbstick Y = 1 (down) | npx iwsdk xr set-gamepad-state axes [{0, 0}, {1, 1}] |
| Jump | Right | A button (index 3) | npx iwsdk xr set-gamepad-state buttons [{3, 1, true}] |
Test 1.1: Slide Forward
npx iwsdk browser screenshot --timeout 20000 2>/dev/null
Save as "before slide".
npx iwsdk xr set-gamepad-state --input-json '{"device":"controller-left","axes":[{"index":0,"value":0},{"index":1,"value":-1}]}' 2>/dev/null
Then: sleep 1
npx iwsdk browser screenshot --timeout 20000 2>/dev/null
Save as "after slide".
Assert: Screenshots show scene moving closer (player moved forward).
Test 1.2: Stop Sliding
npx iwsdk xr set-gamepad-state --input-json '{"device":"controller-left","axes":[{"index":0,"value":0},{"index":1,"value":0}]}' 2>/dev/null
Assert: Player stops moving (subsequent screenshots are identical).
Test 1.3: Slide Backward
npx iwsdk xr set-gamepad-state --input-json '{"device":"controller-left","axes":[{"index":0,"value":0},{"index":1,"value":1}]}' 2>/dev/null
Then: sleep 1
npx iwsdk browser screenshot --timeout 20000 2>/dev/null
Assert: Scene moves away (player retreated).
Release:
npx iwsdk xr set-gamepad-state --input-json '{"device":"controller-left","axes":[{"index":0,"value":0},{"index":1,"value":0}]}' 2>/dev/null
Test 2.1: Snap Turn Right
npx iwsdk browser screenshot --timeout 20000 2>/dev/null
Save as "before turn".
npx iwsdk xr set-gamepad-state --input-json '{"device":"controller-right","axes":[{"index":0,"value":1},{"index":1,"value":0}]}' 2>/dev/null
Then: sleep 0.3
npx iwsdk browser screenshot --timeout 20000 2>/dev/null
Save as "after turn right".
Assert: View rotated ~45 degrees clockwise.
Test 2.2: Release + Snap Turn Left
IMPORTANT: Must release first for edge trigger reset.
npx iwsdk xr set-gamepad-state --input-json '{"device":"controller-right","axes":[{"index":0,"value":0},{"index":1,"value":0}]}' 2>/dev/null
Then: sleep 0.3
Push left:
npx iwsdk xr set-gamepad-state --input-json '{"device":"controller-right","axes":[{"index":0,"value":-1},{"index":1,"value":0}]}' 2>/dev/null
Then: sleep 0.3
npx iwsdk browser screenshot --timeout 20000 2>/dev/null
Assert: View rotated ~45 degrees counter-clockwise (back to roughly original heading).
Release thumbstick:
npx iwsdk xr set-gamepad-state --input-json '{"device":"controller-right","axes":[{"index":0,"value":0},{"index":1,"value":0}]}' 2>/dev/null
Precondition: The right controller must NOT be pointing at any interactable entity.
Test 3.1: Setup — Point Controller at Floor
npx iwsdk xr set-transform --input-json '{"device":"controller-right","position":{"x":0.25,"y":1.5,"z":-0.3},"orientation":{"pitch":-45,"roll":0,"yaw":0}}' 2>/dev/null
Test 3.2: Activate Teleport Arc
npx iwsdk browser screenshot --timeout 20000 2>/dev/null
Save as "before teleport".
npx iwsdk xr set-gamepad-state --input-json '{"device":"controller-right","axes":[{"index":0,"value":0},{"index":1,"value":1}]}' 2>/dev/null
Then: sleep 1
Test 3.3: Release to Teleport
npx iwsdk xr set-gamepad-state --input-json '{"device":"controller-right","axes":[{"index":0,"value":0},{"index":1,"value":0}]}' 2>/dev/null
Then: sleep 0.5
npx iwsdk browser screenshot --timeout 20000 2>/dev/null
Assert: Player position changed (view is from a different location).
Test 4.1: Press A Button
npx iwsdk xr set-gamepad-state --input-json '{"device":"controller-right","buttons":[{"index":3,"value":1,"touched":true}]}' 2>/dev/null
Then: sleep 0.3
npx iwsdk browser screenshot --timeout 20000 2>/dev/null
npx iwsdk xr set-gamepad-state --input-json '{"device":"controller-right","buttons":[{"index":3,"value":0,"touched":false}]}' 2>/dev/null
Assert: View may show momentary elevation change.
npx iwsdk ecs systems 2>/dev/null
Assert:
LocomotionSystem at priority -5TurnSystem at priority 0 with config keys: turningMethod, turningAngle, turningSpeedSlideSystem at priority 0 with config keys: locomotor, inputProvider, maxSpeed, comfortAssist, enableJumpingTeleportSystem at priority 0 with config keys: rayGravity, locomotor, inputProviderVerify Elevator component and ElevatorSystem:
npx iwsdk ecs find --input-json '{"withComponents":["Elevator"]}' 2>/dev/null
Assert: At least 1 entity (the oscillating platform).
npx iwsdk 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.
Kill the dev server:
cd $IWSDK_REPO_ROOT/examples/locomotion && npx iwsdk dev down
Output a summary table:
| Suite | Result |
|---------------------------|-----------|
| 1. Slide Movement | PASS/FAIL |
| 2. Snap Turn | PASS/FAIL |
| 3. Teleport | PASS/FAIL |
| 4. Jump | PASS/FAIL |
| 5. System Registration | PASS/FAIL |
| 6. Stability | PASS/FAIL |
If any suite fails, include which assertion failed and actual vs expected values.
If at any point a transient error occurs (server crash, WebSocket timeout, connection refused, etc.) that is NOT caused by a source code bug:
cd $IWSDK_REPO_ROOT/examples/locomotion && npx iwsdk dev downOnly give up after one retry attempt per suite. If the same suite fails twice, mark it FAIL and continue to the next suite.
Headset position stays constant (relative to XR origin). Verify movement via screenshots.
Position controller away from interactables before testing teleport.
Must reset to center between turns. Holding the stick only fires one turn.
Y = -1 is forward, Y = 1 is backward. For teleport, Y = 1 activates the arc.
Never cache entity indices across page reloads. Always re-discover via npx iwsdk ecs find.