GAME DESIGN DOCUMENT

PLATFORM TARGETS

• Target Hardware:  Meta Quest 3 (Standalone).

• Engine Version:  Unity 6.3 LTS (6000.3.0f1).

• Render Pipeline:  Universal Render Pipeline (URP).

• Target Frame Rate: 100 FPS (Stable) 90 FPS (Minimum).

  • Note:  While 72Hz is the floor for VR, a high-speed racing game requires 90Hz to minimize motion sickness and latency.

• Color Space: Linear (for accurate PBR lighting).

ENGINEERING OPTIMIZATION GUIDANCE

• Physics Step: The physics simulation (Fixed Timestep) should be decoupled from the rendering frame rate but tuned for high-speed precision.

  • Guideline: Aim for a physics step that matches the target refresh rate (e.g., 90Hz = 0.0111s) or a clean divisor to prevent "micro-stutter" in the bike's movement.

• Draw Call Management

  • GPU Instancing:  Preferred for all repeated trackside objects (barriers, crowd silhouettes, distant buildings).

  • Static Batching:  The track chunks (Asphalt/Dirt) should be static batched where possible. This can reduce the number of graphics draw calls.

• Garbage Collection (GC): Zero-allocation code in the Update() loop. Object pooling must be used (rather than instantiation & destruction) for all temporary visual effects (tire particles, UI elements) to prevent frame spikes from GC spikes.

ART OPTIMIZATION GUIDANCE

The Quest 3 is powerful, but it is still a mobile chipset. We must be efficient to save GPU headroom for the "AR Overlay" effects.

• Geometry

  • Strict Budgets:  Prioritize silhouette over surface detail. Use hard edges and smoothing groups effectively.

  • LODs (Level of Detail):  Aggressive LOD transitions for track assets. Distant buildings should be simple cubes.

• Textures & Materials

  • Workflow:  High-to-Low Poly baking. Detail must come from Normal and Roughness maps, not extra triangles.

  • Atlasing:  Combine textures for shared props (e.g., "Street Props Atlas") to reduce draw calls.

  • Compression:  Set the Unity default to ASTC compression for all textures.

• Lighting

  • Baked Lighting:  The environment (Track and City) should use Baked Lightmaps. Real-time lighting on the environment is prohibited.

  • Dynamic Lighting:  Limit real-time lights to One (1) Directional Light (Sun/Moon) and essential bike lights.

VR-SPECIFIC SETTINGS

• Fixed Foveated Rendering (FFR):  Enable at Medium/High. This reduces resolution at the edges of the lens where the player isn't looking, saving significant GPU power.

• Single Pass Instanced Rendering:  Must be enabled in Unity XR settings to render both eyes efficiently.

• Unity Profiler:  Should be used during testing to figure out define resources, leaks, and possibilities of organization.