Add target positions for asteroid orbit and movement

Adds configurable target positions that asteroids can reference:
- Orbit mode: asteroid maintains fixed distance to target via constraint
- MoveToward mode: asteroid velocity redirected toward target

Includes level editor UI for managing targets and asteroid assignments.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/components/editor/AsteroidListEditor.svelte

@@ -1,12 +1,25 @@
 <script lang="ts">
-  import type { AsteroidConfig } from '../../levels/config/levelConfig';
+  import type { AsteroidConfig, TargetConfig } from '../../levels/config/levelConfig';
   import Button from '../shared/Button.svelte';
   import Section from '../shared/Section.svelte';
   import Vector3Input from './Vector3Input.svelte';
   import NumberInput from '../shared/NumberInput.svelte';
   import FormGroup from '../shared/FormGroup.svelte';
+  import Select from '../shared/Select.svelte';
 
   export let asteroids: AsteroidConfig[] = [];
+  export let targets: TargetConfig[] = [];
+
+  $: targetOptions = [
+    { value: '', label: '(None)' },
+    ...targets.map(t => ({ value: t.id, label: t.name }))
+  ];
+
+  const modeOptions = [
+    { value: '', label: '(None)' },
+    { value: 'orbit', label: 'Orbit' },
+    { value: 'moveToward', label: 'Move Toward' }
+  ];
 
   let editingIndex: number | null = null;
   let editingAsteroid: AsteroidConfig | null = null;
@@ -76,6 +89,14 @@
       </FormGroup>
       <Vector3Input label="Linear Velocity" bind:value={editingAsteroid.linearVelocity} step={1} />
       <Vector3Input label="Angular Velocity" bind:value={editingAsteroid.angularVelocity} step={0.1} />
+      <FormGroup label="Target">
+        <Select bind:value={editingAsteroid.targetId} options={targetOptions} />
+      </FormGroup>
+      {#if editingAsteroid.targetId}
+        <FormGroup label="Target Mode">
+          <Select bind:value={editingAsteroid.targetMode} options={modeOptions} />
+        </FormGroup>
+      {/if}
       <div class="edit-actions">
         <Button variant="primary" on:click={handleSave}>Save</Button>
         <Button variant="secondary" on:click={handleCancel}>Cancel</Button>

src/components/editor/LevelConfigEditor.svelte

@@ -12,6 +12,7 @@
   import StarfieldConfigEditor from './StarfieldConfigEditor.svelte';
   import AsteroidListEditor from './AsteroidListEditor.svelte';
   import PlanetListEditor from './PlanetListEditor.svelte';
+  import TargetListEditor from './TargetListEditor.svelte';
 
   export let levelId: string = '';
 
@@ -33,6 +34,7 @@
     { id: 'base', label: '🛬 Base' },
     { id: 'sun', label: '☀️ Sun' },
     { id: 'starfield', label: '✨ Stars' },
+    { id: 'targets', label: '🎯 Targets' },
     { id: 'asteroids', label: '☄️ Asteroids' },
     { id: 'planets', label: '🪐 Planets' }
   ];
@@ -124,6 +126,12 @@
       config.starfield = undefined;
     }
   }
+
+  function ensureTargets() {
+    if (config && !config.targets) {
+      config.targets = [];
+    }
+  }
 </script>
 
 <div class="editor-container">
@@ -170,8 +178,12 @@
         <SunConfigEditor bind:config={config.sun} />
       {:else if activeTab === 'starfield'}
         <StarfieldConfigEditor config={config.starfield} onToggle={handleStarfieldToggle} />
+      {:else if activeTab === 'targets'}
+        {ensureTargets()}
+        <TargetListEditor bind:targets={config.targets} />
       {:else if activeTab === 'asteroids'}
-        <AsteroidListEditor bind:asteroids={config.asteroids} />
+        {ensureTargets()}
+        <AsteroidListEditor bind:asteroids={config.asteroids} targets={config.targets || []} />
       {:else if activeTab === 'planets'}
         <PlanetListEditor bind:planets={config.planets} />
       {/if}

src/components/editor/TargetListEditor.svelte

@@ -0,0 +1,185 @@
+<script lang="ts">
+  import type { TargetConfig } from '../../levels/config/levelConfig';
+  import Button from '../shared/Button.svelte';
+  import Section from '../shared/Section.svelte';
+  import Vector3Input from './Vector3Input.svelte';
+  import FormGroup from '../shared/FormGroup.svelte';
+
+  export let targets: TargetConfig[] = [];
+
+  let editingIndex: number | null = null;
+  let editingTarget: TargetConfig | null = null;
+
+  function generateId(): string {
+    return `target-${Date.now()}-${Math.random().toString(36).substr(2, 9)}`;
+  }
+
+  function handleAdd() {
+    const newTarget: TargetConfig = {
+      id: generateId(),
+      name: `Target ${targets.length + 1}`,
+      position: [0, 0, 0]
+    };
+    targets = [...targets, newTarget];
+    editingIndex = targets.length - 1;
+    editingTarget = { ...newTarget };
+  }
+
+  function handleEdit(index: number) {
+    editingIndex = index;
+    editingTarget = { ...targets[index] };
+  }
+
+  function handleSave() {
+    if (editingIndex !== null && editingTarget) {
+      targets[editingIndex] = editingTarget;
+      targets = targets;
+    }
+    editingIndex = null;
+    editingTarget = null;
+  }
+
+  function handleCancel() {
+    editingIndex = null;
+    editingTarget = null;
+  }
+
+  function handleDelete(index: number) {
+    if (confirm('Delete this target? Asteroids referencing it will lose their target.')) {
+      targets = targets.filter((_, i) => i !== index);
+      if (editingIndex === index) {
+        editingIndex = null;
+        editingTarget = null;
+      }
+    }
+  }
+
+  function formatPosition(pos: [number, number, number]): string {
+    return `${pos[0]}, ${pos[1]}, ${pos[2]}`;
+  }
+</script>
+
+<Section title="Target Positions ({targets.length})">
+  <p class="hint">Targets are positions that asteroids can orbit or move toward.</p>
+
+  <div class="target-header">
+    <Button variant="primary" on:click={handleAdd}>+ Add Target</Button>
+  </div>
+
+  {#if editingTarget !== null}
+    <div class="edit-form">
+      <h4>Edit Target: {editingTarget.name}</h4>
+      <FormGroup label="ID (read-only)">
+        <input type="text" class="settings-input" value={editingTarget.id} disabled />
+      </FormGroup>
+      <FormGroup label="Name">
+        <input type="text" class="settings-input" bind:value={editingTarget.name} />
+      </FormGroup>
+      <Vector3Input label="Position" bind:value={editingTarget.position} step={50} />
+      <div class="edit-actions">
+        <Button variant="primary" on:click={handleSave}>Save</Button>
+        <Button variant="secondary" on:click={handleCancel}>Cancel</Button>
+      </div>
+    </div>
+  {/if}
+
+  {#if targets.length === 0}
+    <p class="empty-message">No targets configured. Add targets for asteroids to orbit or move toward.</p>
+  {:else}
+    <div class="target-table">
+      <table>
+        <thead>
+          <tr>
+            <th>Name</th>
+            <th>ID</th>
+            <th>Position</th>
+            <th>Actions</th>
+          </tr>
+        </thead>
+        <tbody>
+          {#each targets as target, index}
+            <tr class:editing={editingIndex === index}>
+              <td>{target.name}</td>
+              <td class="id-cell">{target.id}</td>
+              <td>{formatPosition(target.position)}</td>
+              <td class="actions">
+                <Button variant="secondary" on:click={() => handleEdit(index)}>Edit</Button>
+                <Button variant="danger" on:click={() => handleDelete(index)}>x</Button>
+              </td>
+            </tr>
+          {/each}
+        </tbody>
+      </table>
+    </div>
+  {/if}
+</Section>
+
+<style>
+  .hint {
+    font-size: 0.9rem;
+    color: var(--color-text-secondary, #888);
+    margin-bottom: 1rem;
+  }
+
+  .target-header {
+    margin-bottom: 1rem;
+  }
+
+  .edit-form {
+    background: var(--color-bg-secondary, #1a1a2e);
+    padding: 1rem;
+    border-radius: 8px;
+    margin-bottom: 1rem;
+  }
+
+  .edit-form h4 {
+    margin: 0 0 1rem 0;
+    color: var(--color-text-primary, #fff);
+  }
+
+  .edit-actions {
+    display: flex;
+    gap: 0.5rem;
+    margin-top: 1rem;
+  }
+
+  .target-table {
+    overflow-x: auto;
+  }
+
+  table {
+    width: 100%;
+    border-collapse: collapse;
+  }
+
+  th, td {
+    padding: 0.5rem;
+    text-align: left;
+    border-bottom: 1px solid var(--color-border, #333);
+  }
+
+  th {
+    background: var(--color-bg-secondary, #1a1a2e);
+    font-weight: 600;
+  }
+
+  tr.editing {
+    background: var(--color-bg-hover, #252540);
+  }
+
+  .id-cell {
+    font-family: monospace;
+    font-size: 0.8rem;
+    color: var(--color-text-secondary, #888);
+  }
+
+  .actions {
+    display: flex;
+    gap: 0.25rem;
+  }
+
+  .empty-message {
+    color: var(--color-text-secondary, #888);
+    font-style: italic;
+  }
+</style>

src/environment/asteroids/rockFactory.ts

@@ -41,6 +41,8 @@ interface RockConfig {
     angularVelocity: Vector3;
     scoreObservable: Observable<ScoreEvent>;
     useOrbitConstraint: boolean;
+    targetPosition?: Vector3;
+    targetMode?: 'orbit' | 'moveToward';
 }
 
 export class RockFactory {
@@ -166,7 +168,9 @@ export class RockFactory {
         angularVelocity: Vector3,
         scoreObservable: Observable<ScoreEvent>,
         useOrbitConstraint: boolean = true,
-        hidden: boolean = false
+        hidden: boolean = false,
+        targetPosition?: Vector3,
+        targetMode?: 'orbit' | 'moveToward'
     ): Rock {
         if (!this._asteroidMesh) {
             throw new Error('[RockFactory] Asteroid mesh not loaded. Call initMesh() first.');
@@ -188,11 +192,13 @@ export class RockFactory {
             linearVelocity,
             angularVelocity,
             scoreObservable,
-            useOrbitConstraint
+            useOrbitConstraint,
+            targetPosition,
+            targetMode
         };
         this._createdRocks.set(rock.id, { mesh: rock, config });
 
-        log.debug(`[RockFactory] Created rock mesh ${rock.id} (hidden: ${hidden})`);
+        log.debug(`[RockFactory] Created rock mesh ${rock.id} (hidden: ${hidden}, target: ${targetMode || 'none'})`);
         return new Rock(rock);
     }
 
@@ -215,8 +221,11 @@ export class RockFactory {
         body.setMotionType(PhysicsMotionType.DYNAMIC);
         body.setCollisionCallbackEnabled(true);
 
-        // Apply orbit constraint if enabled
-        if (config.useOrbitConstraint && this._orbitCenter) {
+        // Handle target-based physics
+        if (config.targetPosition && config.targetMode) {
+            this.applyTargetPhysics(body, config);
+        } else if (config.useOrbitConstraint && this._orbitCenter) {
+            // Legacy: orbit around origin if no specific target
             const constraint = new DistanceConstraint(
                 Vector3.Distance(config.position, this._orbitCenter.body.transformNode.position),
                 DefaultScene.MainScene
@@ -230,7 +239,10 @@ export class RockFactory {
             physicsPlugin.setActivationControl(body, PhysicsActivationControl.ALWAYS_ACTIVE);
         }
 
+        // Apply velocity (may be modified by applyTargetPhysics for moveToward mode)
+        if (!(config.targetPosition && config.targetMode === 'moveToward')) {
             body.setLinearVelocity(config.linearVelocity);
+        }
         body.setAngularVelocity(config.angularVelocity);
 
         // Setup collision handler
@@ -239,6 +251,45 @@ export class RockFactory {
         log.debug(`[RockFactory] Physics initialized for ${rock.id}`);
     }
 
+    /**
+     * Apply target-based physics (orbit or moveToward)
+     */
+    private static applyTargetPhysics(body: PhysicsBody, config: RockConfig): void {
+        if (!config.targetPosition) return;
+
+        if (config.targetMode === 'orbit') {
+            // Create distance constraint to target position
+            // We need a static body at the target position for the constraint
+            const targetNode = new TransformNode(`target-${body.transformNode.id}`, DefaultScene.MainScene);
+            targetNode.position = config.targetPosition;
+            const targetBody = new PhysicsAggregate(
+                targetNode, PhysicsShapeType.SPHERE,
+                { radius: 0.1, mass: 0 },
+                DefaultScene.MainScene
+            );
+            targetBody.body.setMotionType(PhysicsMotionType.STATIC);
+
+            const distance = Vector3.Distance(config.position, config.targetPosition);
+            const constraint = new DistanceConstraint(distance, DefaultScene.MainScene);
+            body.addConstraint(targetBody.body, constraint);
+
+            // Apply original velocity for orbiting
+            body.setLinearVelocity(config.linearVelocity);
+        } else if (config.targetMode === 'moveToward') {
+            // Calculate speed as sum of absolute velocity components
+            const speed = Math.abs(config.linearVelocity.x) +
+                          Math.abs(config.linearVelocity.y) +
+                          Math.abs(config.linearVelocity.z);
+
+            // Direction toward target
+            const direction = config.targetPosition.subtract(config.position).normalize();
+
+            // Final velocity = direction * speed
+            const velocity = direction.scale(speed);
+            body.setLinearVelocity(velocity);
+        }
+    }
+
     private static setupCollisionHandler(body: PhysicsBody, scoreObservable: Observable<ScoreEvent>): void {
         body.getCollisionObservable().add((eventData) => {
             if (eventData.type !== 'COLLISION_STARTED') return;

src/levels/config/levelConfig.ts

@@ -111,16 +111,27 @@ interface PlanetConfig {
     rotation?: Vector3Array;
 }
 
+/**
+ * Target position for asteroids to orbit or move toward
+ */
+export interface TargetConfig {
+    id: string;
+    name: string;           // Display name for editor
+    position: Vector3Array;
+}
+
 /**
  * Individual asteroid configuration
  */
-interface AsteroidConfig {
+export interface AsteroidConfig {
     id: string;
     position: Vector3Array;
     scale: number;  // Uniform scale applied to all axes
     linearVelocity: Vector3Array;
     angularVelocity?: Vector3Array;
     mass?: number;
+    targetId?: string;                      // Reference to target from targets array
+    targetMode?: 'orbit' | 'moveToward';    // How asteroid interacts with target
 }
 
 /**
@@ -155,6 +166,7 @@ export interface LevelConfig {
     startBase?: StartBaseConfig;
     sun: SunConfig;
     starfield?: StarfieldConfig;
+    targets?: TargetConfig[];
     planets: PlanetConfig[];
     asteroids: AsteroidConfig[];
 

src/levels/config/levelDeserializer.ts

@@ -239,6 +239,15 @@ export class LevelDeserializer {
             const asteroidConfig = this.config.asteroids[i];
             const useOrbitConstraints = this.config.useOrbitConstraints !== false;
 
+            // Resolve target position if specified
+            let targetPosition: Vector3 | undefined;
+            if (asteroidConfig.targetId && this.config.targets) {
+                const target = this.config.targets.find(t => t.id === asteroidConfig.targetId);
+                if (target) {
+                    targetPosition = this.arrayToVector3(target.position);
+                }
+            }
+
             // Create mesh only (no physics)
             RockFactory.createRockMesh(
                 i,
@@ -248,7 +257,9 @@ export class LevelDeserializer {
                 this.arrayToVector3(asteroidConfig.angularVelocity),
                 scoreObservable,
                 useOrbitConstraints,
-                hidden
+                hidden,
+                targetPosition,
+                asteroidConfig.targetMode
             );
 
             const mesh = this.scene.getMeshByName(asteroidConfig.id);