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name: 3d-games description: 3D game development principles. Rendering, shaders, physics, cameras. allowed-tools: Read, Write, Edit, Glob, Grep

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.