1. Compare Unity and Unreal Engine. When would you choose each?<\/p>\n
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Unity:<\/strong> C# scripting, great for 2D\/mobile\/indie games, asset store ecosystem, faster iteration. Lower hardware requirements.<\/p>\nUnreal:<\/strong> C++ foundation with Blueprint visual scripting, industry-standard for AAA, superior graphics out-of-the-box, built-in multiplayer framework.<\/p>\n<\/div>\n<\/div>\n\n
2. Explain the game loop and its phases.<\/p>\n
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The game loop runs continuously: Input \u2192 Update \u2192 Render \u2192 Present<\/strong><\/p>\n\nInput:<\/strong> Process player input and system events<\/li>\nUpdate:<\/strong> Game logic, physics, AI, animation updates<\/li>\nRender:<\/strong> Draw objects, apply effects, lighting calculations<\/li>\nPresent:<\/strong> Display frame buffer to screen<\/li>\n<\/ul>\n<\/div>\n<\/div>\n\n
3. What is delta time and why is it crucial in game development?<\/p>\n
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Delta time is the elapsed time between frames. Essential for frame-rate independent movement and animations.<\/p>\n
Usage:<\/strong> position += velocity * deltaTime<\/code> ensures consistent movement regardless of frame rate (30fps vs 60fps vs 144fps).<\/p>\n<\/div>\n<\/div>\n\n
4. Explain the Entity-Component-System (ECS) architecture.<\/p>\n
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Entity:<\/strong> Unique identifier for game objects<\/p>\nComponent:<\/strong> Data containers (Position, Health, Renderer)<\/p>\nSystem:<\/strong> Logic that operates on entities with specific components<\/p>\nBenefits:<\/strong> Better performance, modularity, memory locality. Used in Unity DOTS and custom engines.<\/p>\n<\/div>\n<\/div>\n\n
5. How do you handle different screen resolutions and aspect ratios?<\/p>\n
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\nViewport scaling:<\/strong> Scale viewport while maintaining aspect ratio<\/li>\nUI anchoring:<\/strong> Anchor UI elements to screen edges or safe areas<\/li>\nDynamic layouts:<\/strong> Responsive UI that adapts to different sizes<\/li>\nAsset variants:<\/strong> Different texture sizes for various devices<\/li>\n<\/ul>\n<\/div>\n<\/div>\n\n
6. What are shaders and when would you write custom ones?<\/p>\n
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Shaders are GPU programs that control rendering. Types: Vertex (geometry transformation), Fragment\/Pixel (color calculation).<\/p>\n
Custom use cases:<\/strong> Unique visual effects, stylized rendering (toon shading), post-processing effects, optimization for specific art style.<\/p>\n<\/div>\n<\/div>\n\n
7. Explain object pooling and its importance in games.<\/p>\n
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Pre-allocate objects and reuse them instead of constant instantiation\/destruction. Critical for bullets, enemies, particle effects.<\/p>\n
Benefits:<\/strong> Reduces garbage collection, prevents frame drops, more predictable performance. Essential for mobile and VR games.<\/p>\n<\/div>\n<\/div>\n\n
8. How do you optimize game performance for different platforms?<\/p>\n
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\nMobile:<\/strong> Lower poly counts, compressed textures, efficient shaders<\/li>\nConsole:<\/strong> Utilize specific hardware features, fixed specs optimization<\/li>\nPC:<\/strong> Scalable quality settings, multiple resolution support<\/li>\nVR:<\/strong> Maintain 90fps, reduce motion sickness, optimize for stereoscopic rendering<\/li>\n<\/ul>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/rect><\/rect><\/path><\/path><\/path><\/path><\/path><\/path><\/path><\/path><\/svg>Game Physics & Math (Questions 9-15)<\/h2>\n\n
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9. Explain collision detection methods and their trade-offs.<\/p>\n
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\nAABB:<\/strong> Fast, simple, good for UI and 2D games<\/li>\nSphere collision:<\/strong> Very fast distance check, good for rough detection<\/li>\nMesh collision:<\/strong> Most accurate but expensive, use for static geometry<\/li>\nSpatial partitioning:<\/strong> Octrees\/quadtrees to reduce collision checks<\/li>\n<\/ul>\n<\/div>\n<\/div>\n\n
10. How do you implement smooth character movement?<\/p>\n
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Interpolation:<\/strong> Smooth movement between network updates<\/p>\nAcceleration\/Deceleration:<\/strong> Gradually change velocity instead of instant stops<\/p>\nPhysics integration:<\/strong> Use Rigidbody for natural movement, CharacterController for precise control.<\/p>\n<\/div>\n<\/div>\n\n
11. What is the difference between kinematic and dynamic physics bodies?<\/p>\n
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Dynamic:<\/strong> Affected by physics forces, gravity, collisions. Used for physics objects, projectiles.<\/p>\nKinematic:<\/strong> Moved by script, affects others but not affected. Used for player controllers, moving platforms.<\/p>\n<\/div>\n<\/div>\n\n
12. How do you calculate line of sight for AI characters?<\/p>\n
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Use raycasting from AI to target. Check if ray hits obstacles before reaching target.<\/p>\n
Optimization:<\/strong> Use layers to ignore certain objects, cache results, check periodically rather than every frame.<\/p>\n<\/div>\n<\/div>\n\n
13. Explain quaternions and why they’re used for rotations.<\/p>\n
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Quaternions represent 3D rotations without gimbal lock. Four components (x, y, z, w) represent axis and angle.<\/p>\n
Advantages:<\/strong> No gimbal lock, smooth interpolation (SLERP), compact representation, efficient composition.<\/p>\n<\/div>\n<\/div>\n\n
14. How do you implement realistic projectile physics?<\/p>\n
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Apply gravity to velocity over time: velocity.y += gravity * deltaTime<\/code><\/p>\nAdvanced:<\/strong> Air resistance, spin effects, trajectory prediction for AI aiming, parabolic motion calculations.<\/p>\n<\/div>\n<\/div>\n\n
15. What is spatial partitioning and how does it improve performance?<\/p>\n
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Dividing game world into regions to quickly eliminate objects from expensive operations.<\/p>\n
Types:<\/strong> Quadtree (2D), Octree (3D), Grid-based. Reduces collision checks from O(n\u00b2) to O(n log n) or better.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/rect><\/line><\/line><\/svg>Rendering & Graphics (Questions 16-21)<\/h2>\n\n
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16. Explain the graphics pipeline from vertices to pixels.<\/p>\n
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\nVertex processing (transform coordinates)<\/li>\n Primitive assembly (triangles from vertices)<\/li>\n Rasterization (convert to pixels)<\/li>\n Fragment\/pixel processing (lighting, textures)<\/li>\n Per-pixel operations (depth test, blending)<\/li>\n<\/ol>\n<\/div>\n<\/div>\n\n
17. What are draw calls and how do you minimize them?<\/p>\n
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Draw calls are CPU commands to GPU to render objects. Each call has overhead.<\/p>\n
\nBatching:<\/strong> Combine similar objects into single draw call<\/li>\nAtlasing:<\/strong> Pack multiple textures into one<\/li>\nInstancing:<\/strong> Render many identical objects efficiently<\/li>\n<\/ul>\n<\/div>\n<\/div>\n\n
18. How do you implement level-of-detail (LOD) systems?<\/p>\n
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Switch between different mesh\/texture quality based on distance or screen size.<\/p>\n
Implementation:<\/strong> Pre-generate LOD models, calculate distance\/screen percentage, smoothly transition between levels to avoid popping.<\/p>\n<\/div>\n<\/div>\n\n
19. Explain frustum culling and occlusion culling.<\/p>\n
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Frustum culling:<\/strong> Don’t render objects outside camera view<\/p>\nOcclusion culling:<\/strong> Don’t render objects blocked by other objects. More complex but greater performance gains in dense scenes.<\/p>\n<\/div>\n<\/div>\n\n
20. How do you optimize textures for different platforms?<\/p>\n
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\nCompression:<\/strong> DXT (PC), PVRTC (iOS), ETC (Android), ASTC (modern)<\/li>\nMipmapping:<\/strong> Pre-generated smaller versions for distance rendering<\/li>\nTexture streaming:<\/strong> Load higher quality textures as needed<\/li>\nAtlas optimization:<\/strong> Pack related textures, minimize wasted space<\/li>\n<\/ul>\n<\/div>\n<\/div>\n\n
21. What is deferred rendering and when would you use it?<\/p>\n
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Render geometry to multiple buffers (G-buffer), then apply lighting in screen space.<\/p>\n
Benefits:<\/strong> Efficient with many lights, decouples shading complexity. Drawbacks:<\/strong> Memory intensive, transparency issues.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/path><\/path><\/path><\/svg>Gameplay Programming (Questions 22-27)<\/h2>\n\n
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22. How do you implement a finite state machine for AI behavior?<\/p>\n
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States represent AI behaviors (Idle, Patrol, Chase, Attack). Transitions based on conditions.<\/p>\n
Implementation:<\/strong> Enum for states, switch statement or state classes, transition conditions, enter\/exit methods for each state.<\/p>\n<\/div>\n<\/div>\n\n
23. Explain pathfinding algorithms used in games.<\/p>\n
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A*:<\/strong> Most common, uses heuristic to guide search efficiently<\/p>\nDijkstra:<\/strong> Guarantees shortest path but slower<\/p>\nOptimizations:<\/strong> Hierarchical pathfinding, jump point search, flow fields for groups, nav mesh for 3D worlds.<\/p>\n<\/div>\n<\/div>\n\n
24. How do you design a flexible damage system?<\/p>\n
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Create damage info struct with damage amount, type, source, modifiers. Use events for damage dealt\/received.<\/p>\n
Features:<\/strong> Damage types (physical, magic), resistances, critical hits, damage over time, area damage.<\/p>\n<\/div>\n<\/div>\n\n
25. What is an event system and how do you implement it?<\/p>\n
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Decoupled communication between game systems. Publishers send events, subscribers listen.<\/p>\n
Unity:<\/strong> UnityEvents, C# events. Custom:<\/strong> Observer pattern, message queues, type-safe delegates.<\/p>\n<\/div>\n<\/div>\n\n
26. How do you handle game saves and serialization?<\/p>\n
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\nBinary:<\/strong> Fast, compact, but version fragile<\/li>\nJSON\/XML:<\/strong> Human-readable, flexible, larger files<\/li>\nCustom format:<\/strong> Optimized for your data structures<\/li>\nConsiderations:<\/strong> Save game versioning, corrupted save handling, incremental saves<\/li>\n<\/ul>\n<\/div>\n<\/div>\n\n
27. Explain how to implement smooth camera following.<\/p>\n
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Use interpolation: camera.position = Vector3.Lerp(camera.position, target.position, dampening * deltaTime)<\/code><\/p>\nAdvanced:<\/strong> Look-ahead based on player velocity, dead zones for small movements, spring-damper systems.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/path><\/circle><\/path><\/path><\/svg>Multiplayer & Optimization (Questions 28-30)<\/h2>\n\n
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28. How do you handle network lag and packet loss in multiplayer games?<\/p>\n
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