Lecture on Unity Optimization for Mobile Games

Audience Considerations

• Mostly programmers familiar with Unity
• Majority have over 5 years of experience
• Primarily developing for low-end Android handsets

Main Focus: Achieving 60 FPS with Unity's URP

Key Metrics and Profiling

• 60 FPS: Requires 16 ms per frame
  • Low-end handsets may target 30 ms
• Performance Bottlenecks: Identify if CPU or GPU bound
  • Use Unity Profiler to analyze compute time
  • Check physics, animations, particle effects, etc.

Using URP (Universal Render Pipeline)

• Pipeline Assets: Create multiple pipeline assets for different devices and configurations
  • Analyze device performance during loading screens
  • Classify devices into six buckets (very low-end to ultra-high-end)
• Quality Settings: Customize settings for each bucket
  • Adjust asset loading times, shadow quality, texture sizes, etc.
• Key Configurations:
  • Shadow resolution, cascading shadows
  • Texture compression (e.g., crunch compression)
  • Per-pixel vs. vertex lighting
  • Use simple lit shaders for performance

Specific Optimization Techniques

• Shadows:
  • Real-time shadows work well on medium to high-end devices
  • Cascading shadows for large scenes
  • Manual placement of contact shadows for low-end devices
• Lighting:
  • Use vertex lighting for low-end devices
  • Limit per-pixel lighting to high-end settings
  • Multiple light settings (e.g., three directional lights for characters)
• Set Pass Calls: Aim to keep below 100
  • Use Unity's Frame Debugger to analyze
  • Group objects to minimize different materials
• Triangle Count: Keep around 150K to avoid thermal issues
  • Culling settings to manage scene complexity
• Post Processing:
  • Use extensively for medium to ultra-high-end
  • Disable for low-end to prevent heat issues
• Downsampling:
  • Use the setResolution function to reduce rendering resolution
  • Don’t go below 70% of the native resolution

Other Tips

• Texture Compression: Enable crunch compression to reduce file size
• Dynamic Prefabs: Use shared materials to avoid instance-related set pass issues

Considerations for VR on Mobile

• Resolution: Maintain high resolution; avoid downsampling
• Scene Complexity: Avoid large open-world scenes
• Optimizations: Similar to mobile, focusing on light baking, compressed textures, etc.

Final Points

• Pay close attention to profiling data
• Use Unity tools like Frame Debugger for detailed analysis
• Customize optimizations based on device capabilities and game requirements

Q&A

• VR Optimization: Maintain high resolution and avoid large scenes
• Dynamic Prefabs: Use shared materials to reduce set pass calls

Note: The speaker is available for further questions and help after the session.