D Games

# 3D Game Development

> Principles for 3D game systems.

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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 |

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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

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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

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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

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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

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6. Level of Detail (LOD)

LOD Strategy

| Distance | Model |

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

| Near | Full detail |

| Medium | 50% triangles |

| Far | 25% or billboard |

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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 |

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

When to Use

This skill is applicable to execute the workflow or actions described in the overview.