3d Games

3D Game Development

> Principles for 3D game systems.

1. Rendering Pipeline

Stages

1. Vertex Processing → Transform geometry
2. Rasterization → Convert to pixels
3. Fragment Processing → Color pixels
4. Output → To screen

Optimization Principles

| Technique | Purpose |

|-----------|---------|

| Frustum culling | Don't render off-screen |

| Occlusion culling | Don't render hidden |

| LOD | Less detail at distance |

| Batching | Combine draw calls |

2. Shader Principles

Shader Types

| Type | Purpose |

|------|---------|

| Vertex | Position, normals |

| Fragment/Pixel | Color, lighting |

| Compute | General computation |

When to Write Custom Shaders

• Special effects (water, fire, portals)
• Stylized rendering (toon, sketch)
• Performance optimization
• Unique visual identity

3. 3D Physics

Collision Shapes

| Shape | Use Case |

|-------|----------|

| Box | Buildings, crates |

| Sphere | Balls, quick checks |

| Capsule | Characters |

| Mesh | Terrain (expensive) |

Principles

• Simple colliders, complex visuals
• Layer-based filtering
• Raycasting for line-of-sight

4. Camera Systems

Camera Types

| Type | Use |

|------|-----|

| Third-person | Action, adventure |

| First-person | Immersive, FPS |

| Isometric | Strategy, RPG |

| Orbital | Inspection, editors |

Camera Feel

• Smooth following (lerp)
• Collision avoidance
• Look-ahead for movement
• FOV changes for speed

5. Lighting

Light Types

| Type | Use |

|------|-----|

| Directional | Sun, moon |

| Point | Lamps, torches |

| Spot | Flashlight, stage |

| Ambient | Base illumination |

Performance Consideration

• Real-time shadows are expensive
• Bake when possible
• Shadow cascades for large worlds

6. Level of Detail (LOD)

LOD Strategy

| Distance | Model |

|----------|-------|

| Near | Full detail |

| Medium | 50% triangles |

| Far | 25% or billboard |

7. Anti-Patterns

| ❌ Don't | ✅ Do |

|----------|-------|

| Mesh colliders everywhere | Simple shapes |

| Real-time shadows on mobile | Baked or blob shadows |

| One LOD for all distances | Distance-based LOD |

| Unoptimized shaders | Profile and simplify |

> Remember: 3D is about illusion. Create the impression of detail, not the detail itself.