SE 350 – Programming Games Lecture 12: Core Mechanics Lecturer: Gazihan Alankuş 2/10/20121

Today’s Lecture is Different We will learn about elements of core mechanics We will identify them in your game ideas I expect you to think and participate We won’t finish all of them today Some slides have questions. Ask them to yourself afterwards and answer them. – This will help you improve your game.

Core Mechanics Space Objects, attributes and states Actions Rules and Goals Skill Chance [Jesse Schell, The Art of Game Design] Rethink your game idea with these in mind Keep these in mind while improving your game

Core Mechanics Space Objects, attributes and states Actions Rules and Goals Skill Chance

Space Where things exist – Discrete vs. continuous – Dimensions (2D, 3D) – Bounded areas, connected or not – Nested spaces Most of your games are continuous 2D and 3D

Questions: Space Is the space discrete or continuous? How many dimensions? What are the boundaries? Are there sub-spaces? (other scenes) Are there multiple ways of modeling your game’s space?

Core Mechanics Space Objects, attributes and states Actions Rules and Goals Skill Chance

Objects, Attributes and States Object Attribute Value Implemented as variables in components

Example Ghost in Pac-Man Position Objective Direction (100, 200) Avoid Pac-Man left (state machine) Object Attribute Value Secrets?

Questions: Objects, Attributes and States What are the objects in the game? What are their attributes? What are the possible states for each attribute? – How do attributes change state? Any secret attributes?

Core Mechanics Space Objects, attributes and states Actions Rules and Goals Skill Chance

Actions What can players do? – “Verbs” of game mechanics Operative actions – Move a checker forwards Resultant actions (more strategic actions) – Force the opponent to make an unwanted move

Actions: Emergent Gameplay Interesting resultant actions that emerge out of users’ behaviors – Identify them, nurture them Tips to support this – Add more verbs – Make verbs act on many objects – Goals can be achieved more than one way – Multiple avatars – Actions that change constraints

Questions: Actions What are the actions? – Which ones are operative? – Which ones are resultant? What objects do they act on? How many ways can players achieve their goals? Can users change constraints? What resultant actions do you want to see? Are you happy with resultant/operative ratio? What actions do players wish they could do? – Can you enable them as operative or resultant?

Core Mechanics Space Objects, attributes and states Actions Rules and Goals Skill Chance

Rules Tie together – Space – Objects – Actions – Consequences of actions – Constraints on actions  Goals You can’t just tell them to do something unless you set up the rules to favor it

Parlett’s Rule Analysis

Goals Concrete, understandable Achievable Rewarding Short-term Long-term Series of goals

Questions: Rules and Goals What are the foundational rules? What are the related operational rules? Are there different modes for rules? What is the ultimate goal? – Is it clear? Are different goals related to each other in a meaningful way?

Core Mechanics Space Objects, attributes and states Actions Rules and Goals Skill Chance

Skill Users’ levels of ability Categories – Physical skills DDR, guitar hero – Mental skills Puzzles – Social skills Most multiplayer games

Skill Balance difficulty and skill for best experience

Questions: Skill What skills does my game require from user? Are there categories of skill that I’m missing? Which skills are dominant? Are these skills creating the experience that I want? Does the game demand the right level of skill?

Core Mechanics Space Objects, attributes and states Actions Rules and Goals Skill Chance

Things happening randomly in the game Uncertainty -> Surprises -> Good! A simple random function may not be enough UniformGaussian

Chance Random seed Always different values Fixed seed Same sequence of values

Randomization in Unity Random.seed: if you give the same seed you get the same sequence of values Random.value: Get a uniform random value in [0, 1] Random.insideUnitSphere: Get a Vector3 inside a sphere with radius 1 Random.insideUnitCircle: Get a Vector2 inside a circle with radius 1 Random.onUnitSphere: Get a Vector3 on the surface of a sphere with radius 1 Random.rotation: Get a random rotation as a quaternion Random.Range(min : float, max : float): Get a random value in [min, max] Random.Range(min : int, max : int): Get a random value in [min, max)

Getting Chance Right is Tricky Calculate probabilities Make sure undesirable edge cases do not happen

Risk Taking Expected probability vs. trust in own skill Example – Monsters appear randomly – What are the odds of me killing a monster if one would find me in that room? High? -> will risk going in Low? -> will not risk

Questions: Chance What in your game is truly random? – What parts just feel random? Does randomness give – Positive feelings (excitement and challenge) – Negative feelings (hopelessness and lack of control) Would changing my probability distribution curves improve my game? Do players have a chance to take interesting risks in the game?

Core Mechanics Space Objects, attributes and states Actions Rules and Goals Skill Chance Rethink your game idea with these in mind Ground your decisions with these Later in your presentations inform us how they influenced your designs