Gameplay Systems

Manage things such as:

• Interaction rules between objects
• Player objectives
• success/fail criteria
• Player abilities
• overall flow
• number and types of non-player entities

Sometimes referred to as "game mechanics", "G-factor"

Game world elements

• Static Elements:
  • don't change or interact with things during gameplay
  • terrain, buildings, roads, bridges
  • Allows for optimization since we don't have to worry about alot of logic for managing these
  • Static geometry
  • Brush geometry: a shape made up of a collection of convex volumes, easy to make and used for prototyping
• Dynamic elements:
  • Objects/elements that can change/interact with each other
  • characters, vehicles, weaponry, floating power-ups and health packs, collectible objects, particle emitters, dynamic lights
• 

World Chunks

• Split up the world into multiple sections
  • Such as levels, world areas, etc.
• Helps memory usage/resources since don't have to load everything at once
• 
• 

Game Objects

• Referred to as GO
• An object-oriented model, uses inheritance
• Can be instanced; each has a type:
  • Pacman has 1 pacman instance, 5 ghost instances, and 100 pellet instances
• The "object model" can define the C++ interface or by a formal design language, such as the OMT object model
  • Microsoft Excel has an object model which allows external programs to control excel (API/interface)

Tool side vs Runtime design

• Tools for creation might have their own interface/language/model different from the game engine, which is converted during the asset conversion pipeline
• The tool-side object model is defined by the set of game object types seen by the designers within the world editor.
• The runtime object model is the model used by the engine/language used during runtime

Data-driven game engine

• Much of the logic/work in an object/asset is defined and implemented at the tool-side/asset creation stage.
• The engine supports reading the tool-side logic/is abstracted to read,parse,run what is defined within the data itself
• This requires extra work on the engine side in terms of implementation, however can pay off by the improved "iteration time" from the asset developer
  • Iteration time = time needed between modifying an asset and seeing the result in the game
• Need to be careful when trying to implement this as it can be time consuming, complex, and bug ridden; may be easier to hard code stuff

Game world editor examples

• Radiant from Quake/Doom engines
  • 
• Hammer (prev. called Worldcraft, The Forge) from Source engine from Valve
  • 
• CRYENGINE from crytek
  • 

Game world editor features

• World chunk creation/management
• Perspective/Orthogonal world views
• Navigation, e.g. via WASD, object centering
• Object selection via raycasts or rubber-band select
• Property Grids: Show and modify object properties
  • 
• Light Objects
• Particle Emitteres
• Sound Sources
• Event Regions
• Splines: Catmull-Rom splines commonly used
• AI Nav Meshes: define areas the AI can navigate through
• Custom Data
• Save/Load in formats such as binary, JSON, XML
• Rapid Iteration/Round Trip Time: want quick time between change and viewing the result