Chapter 14 Part 1: Core Game Mechanics By Nolan Driessen

What are Core Game Mechanics? ● Core Game Mechanics consist of the data and the algorithms that precisely define the game's central rules and internal operations. ● The core mechanics of a game determine how that game actually operates: what its rules are and how the player interacts with them. ● Core game mechanics often refer to the algorithms programmers use to implement your designs ● They should all work together to provide a good game experience

5 types of core mechanics ● Physics – the science of motion and force ● Internal Economies – rules governing quantifiable resources ● Progression Mechanisms – Mechanics that govern the players progress through a series of challenges ● Tactical maneuvering – Movement and control of a space or region ● Social Interaction – Rules controlling relationships between players

● Core Mechanics based on physics often use some form of modified Newtonian mechanics

Functions of Core Game Mechanics ● The relationship between the game engine and the core mechanics is extremely close ● Core game mechanics work behind the scenes and keep track of everything that occurs 1)They operate the internal economy of the game 2)Present Challenges 3)Accept and implement player actions 4)Detect victory or loss 5)Operate Artificial Intelligence

Turn Based vs Real Time ● In turn based games the core mechanics do nothing at all until the player has made their decisions ● Once complete the core mechanics will compute the effects of the actions taken

Key Concepts ● Resources: ● This refers to the types of objects that the game can move or exchange ● Represented with numeric quantities which have arithmetic operations preformed onto them ● Core mechanics define process which these resources are created, used, traded, destroyed etc.

Key Concepts ● Entities: ● Represents the state of some element in the game world ● The state of a light switch, on or off, could be an entity ● While a resource defines a type of thing, an entity represents the specific instance of that thing

Types of Entities ● Simple: A single attribute that is stored. Can be symbolic or numeric. ● Gold, score or a light switch are all examples of simple entities ● Compound: When more than one attribute is required to describe an entity ● Wind with direction and magnitude, or a players inventory filled with multiple items ● Attributes within compound entities can be entities.

Types of Entities ● Unique: Used when the game contains exactly one entity of a particular type ● Player avatar is usually a unique entity ● Other objects such as a football in a football game ● Some entities, regardless of their type, can have their own mechanics

Key Concepts ● Mechanics: ● Document how the game world and everything within it behave ● State the relationship among entities and the conditions that trigger events and processes ● Mechanics do not necessarily operate throughout the whole game, ones that do are called Global Mechanics

Mechanics ● Relationships Among Entities: ● If one entity depends on another this relationship must be specified ● Once enough experience has been gained, level up ● Can be a simple numeric formula or state based ● Character Level = Experience Points / 1000

Mechanics ● Events and Processes: ● An event is a specific change that happens once triggered by a condition ● When Link picks up a heart, his health increases by one ● A process refers to a sequence of activities that continues until stopped

Mechanics ● Conditions: ● Used to define what causes an event as well as when to start or stop a process ● Conditional statements often take the form of if statements or while loops

Key Concepts ● Numeric and Symbolic Relationships: ● Relationships between entities can be either numeric or symbolic ● It is very important to precisely define these relationships in terms of how they should be presented

Relationships ● Numeric: ● Defined in terms of numbers and arithmetic operations ● 50 loaves of bread can be baked from 1 sack of flour and 4 buckets of water ● Must be careful of divide by zero errors and unexpected behaviour from corner cases of each formula ● Speed = weight of supplies / (number of horses – number of followers) ● This can have a negative value or divide by zero error in the right cases

Relationships ● Symbolic: ● Symbolic relationships cannot be manipulated mathematically ● Each state that can be represented must be specified ● A traffic light can have three states, red yellow and green. A driving NPC must have a relationship to each of these states written into their AI

The Internal Economy ● An economy is a system where resources are produced, consumed and exchanged in quantifiable amounts ● Many games have some form of internal economy, which varies in complexity. ● There are many aspects of economies which will be covered here

The Internal Economy ● Sources: ● A source is a mechanic through which a resource or entity is introduced to the game ● Spawn points in shooters which introduce enemies into the game are an example of a source ● Sources can be limited or unlimited ● In monopoly crossing Go is an unlimited resource, however buying hotels and houses is limited ● Production rates must be well defined

The Internal Economy ● Drains: ● A drain is a mechanic that consumes resources ● Firing a gun in a shooter permanently removes bullets from the game ● Players want to know why a resource disappears from their game, as well as what benefit they gained from using those resources. ● Explain your drains!