Add satellite names system - Entity hierarchy with animations

[wannerdev]

Description

Alternative implementation of satellite naming system with fade animations, zoom-based visibility, and enhanced visual polish.

Implementation Approach

This is Implementation B - Entity Hierarchy approach with animations and dynamic visibility.

Key Differences from Implementation A

• Fade Animations: Labels fade in over 0.5 seconds when spawned
• Zoom-Based Visibility: Labels hide when zoomed out (levels 3-4)
• Orphan Cleanup: Automatic cleanup of labels when satellites despawn
• Smooth Transitions: Visual polish with animated appearance

Changes

• Created satellite_names_advanced module
• Added LabelFade component for animation state
• Implemented animate_label_fade system for smooth transitions
• Added update_label_visibility system for zoom-based hiding
• Implemented cleanup_orphaned_labels for automatic cleanup
• Labels start at 0% alpha and fade to 90% over 0.5 seconds
• Integrated into both mouse and touch launch functions

Animation System

Fade-In Animation

LabelFade {
    elapsed: 0.0,
    duration: 0.5,
    fade_in: true,
}

• Labels spawn with 0% alpha (transparent)
• Fade to 90% alpha over 0.5 seconds
• Smooth transition using linear interpolation
• Component removed after animation completes

Zoom-Based Visibility

• Zoom Levels 0-2: Labels visible (zoomed in)
• Zoom Levels 3-4: Labels hidden (zoomed out)
• Prevents label clutter when viewing full solar system
• Automatic visibility updates based on camera zoom

Orphan Cleanup

• Checks if parent satellite still exists
• Automatically despawns labels of destroyed satellites
• Prevents memory leaks from orphaned entities
• Runs every frame for immediate cleanup

Technical Implementation

Fade Animation System

• Queries labels with LabelFade component
• Updates alpha based on elapsed time
• Uses clamp(0.0, 1.0) for safe interpolation
• Removes component when animation completes
• Supports both fade-in and fade-out (extensible)

Visibility Management

• Queries camera zoom level
• Updates all label visibility based on zoom
• Uses Bevy's Visibility component
• Efficient: Only updates when zoom changes

Cleanup System

• Queries labels with Parent component
• Checks if parent exists in satellite query
• Despawns orphaned labels immediately
• Prevents entity buildup over time

Benefits Over Implementation A

• Smoother UX: Fade-in animations feel more polished
• Better Performance: Labels hide when not needed (zoomed out)
• Cleaner Code: Automatic cleanup prevents bugs
• More Professional: Animated transitions enhance game feel
• Scalable: Works well with many satellites

Visual Design

• Animation: 0.5 second fade-in from transparent
• Final Alpha: 90% (subtle but readable)
• Zoom Threshold: Levels 0-2 visible, 3-4 hidden
• Position: Same as Implementation A (below satellite)
• Font: Same retro aesthetic

Performance

• Minimal impact: Animations only on labeled satellites
• Efficient: Visibility system reduces rendering when zoomed out
• Clean: Automatic cleanup prevents entity accumulation
• Scalable: Works with unlimited satellites

Testing

• Launch satellites and verify labels fade in smoothly
• Zoom out (levels 3-4) and verify labels disappear
• Zoom in (levels 0-2) and verify labels reappear
• Destroy satellites and verify labels cleanup automatically
• Launch 10+ satellites and check no performance issues
• Verify animations don't stutter or lag

Comparison with Implementation A

Feature	Implementation A	Implementation B
Label Spawning	Instant	Fade-in animation
Visibility	Always on	Zoom-based
Cleanup	Automatic (parent-child)	Explicit orphan check
Visual Polish	Basic	Enhanced
Performance	Good	Better (zoom hiding)
Complexity	Simple	Moderate

Future Enhancements

• Label pool system for reusing entities
• Fade-out animation when satellites despawn
• Dynamic label updates based on satellite state
• Color-coded labels by satellite type
• Text outline for better readability

Related Feature

Implements: Satellite Names System (Entity Hierarchy with Animations)