Lecture_002

Layers of Game Engine

• Tool Layer: game editor

• Function Layer: Rendering, Animation, Physics, Camera, Script

• Resource Layer: geometry, sound, and other data

• Core Layer: Libraries and Utility Code

• Platform Layer: platform level compatibility and I/O

Resources Layer

Offline Resource Importing

• .xml or .ast file for defining relationship between assets and its connection to game engine

• Pre-processing compressed data during compile time to make loading data faster

• GUID: each assets is assigned with a global identification ID (good for moving resources)

Runtime Asset Manager: a in-memory system to reference assets

• "life cycles": when a resource should be loaded, and unloaded

• different resource have different "life cycles"

• garbage collection and deferred loading

Assets Types:

• 3D model

• Texture

• Material

• Font

• Skeleton

• Collision

• Physics

• World / Map

Function Layer

Ticks: plank time

Note that what belongs in function layer is still in debate. Some game-specific logic might also be in function layer.

Core Layer

Math Library:

• Linear Matrix Algebra

Data Structure:

• Example: tree, vectors, map, heap, queue, linked list, array, stack, hashing

• Goal: avoid fragment memory

• For: animation fragment sequence, skeleton tree

Often, the standard implementation of data structure is not enough. Game engine needs to have its own specific data structure for better performance on specific task.

Memory Management:

• Major bottlenecks of game engine

  • Memory Pool / Allocator
  • Reduce cache miss
  • Memory Alignment

• Polymorphic Memory Resource (PMR)

• 3 Basic Rules

  • Put related memory together (Locality / Diffusion)
  • Access them in a sequence
  • Allocate and de-allocate as a block

Platform Layer

Virtualize Platforms

• Supports Platform: Windows, MacOS, Linux

• Supports Library: OpenGL, DirectX11, DirectX12, Vulkan

• Supports Chips: M1, x86_64, x32

Tool Layer

Graphical Interface and Editors