Game Engine Architecture

48 1. Introduction

z a network of path nodes or roaming volumes, that defi nes areas or paths

where AI characters are free to move without fear of colliding with static

world geometry;

z simplifi ed collision information around the edges of each free-roaming

area;

z knowledge of the entrances and exits from a region, and from where in

each region an enemy might be able to see and/or ambush you;

z a path-fi nding engine based on the well-known A* algorithm;

z hooks into the collision system and world model, for line-of-sight (LOS)

traces and other perceptions;

z a custom world model which tells the AI system where all the entities of

interest (friends, enemies, obstacles) are, permits dynamic avoidance of

moving objects, and so on.

Kynapse also provides an architecture for the AI decision layer, including

the concept of brains (one per character), agents (each of which is responsible

for executing a specifi c task, such as moving from point to point, fi ring on an

enemy, searching for enemies, etc.), and actions (responsible for allowing the

character to perform a fundamental movement, which oft en results in playing

animations on the character’s skeleton).

1.6.16. Game-Specifi c Subsystems

On top of the gameplay foundation layer and the other low-level engine com-

ponents, gameplay programmers and designers cooperate to implement the

features of the game itself. Gameplay systems are usually numerous, highly

varied, and specifi c to the game being developed. As shown in Figure 1.30,

these systems include, but are certainly not limited to the mechanics of the

player character, various in-game camera systems, artifi cial intelligence for

the control of non-player characters (NPCs), weapon systems, vehicles, and

GAME-SPECIFIC SUBSYSTEMS

Game-Specific Rendering

Terrain Rendering Water Simulation & Rendering

etc.

Player Mechanics

Collision Manifold Movement

State Machine & Animation

Game Cameras

Player-Follow Camera Through CamDebug Fly-

Fixed Cameras Scripted/Animated Cameras

AI

Sight Traces & Perception Path Finding (A*)

Camera-Relative Controls (HID) Goals & Decision-Making (Engine Interface)Actions

Weapons Power-Ups Vehicles Puzzles etc.

Figure 1.30. Game-specifi c subsystems.