This exam is starting on April 27 at 10:30 am and ending by 12:30 pm - - PowerPoint PPT Presentation

• The Kennesaw State University Codes of Conduct applies to this exam.
• This exam is starting on April 27 at 10:30 am and ending by 12:30 pm on

Sunday, April 28 via D2L

• ONLY one attempt.
• Once you start the exam, you will have 2 hours to finish it.
• The exam is open everything.
• This is an individual exam. Please do not discuss the contents of the exam

with your classmates or anyone else.

• The weightage of this exam towards your overall course grade is 30%.
• For the questions related to math or drawing figure, please feel free to do

it on a paper and scan/take a picture as your submission.

• Please email me at rguo@kennesaw.edu if you have any questions
• Good luck!

The Benefits of Guidelines

• Elimination of hype
• Clarity and certainty
• Ease of drafting schedules and test plans
• Varying from the guidelines

Documentation

• Concept Doc
• Very small (2 or 3 pages)
• Only has the core concepts
• “Sales” Doc
• To obtain financing
• Functional Specification
• Much larger
• What the game is supposed to do
• Technical Specification
• How it should do it

*Part of the design doc

Elevator Pitch

• Elevator Pitch
• Should be able to describe the game in 2 or 3 sentences (or less)

My game is a cross between Borderlands 2 and My Pretty Pony in which the players hunt pink ponies from Hell.

+ = fun

General Concept Docs

• Story
• Characters
• Environment/Level
• Gameplay
• Art Description
• Sound
• User Interface and Controls

Sales Doc

• To obtain money
• It has much of the Concept Doc in it, plus
• A Market Study
• Are there other games that are similar?
• Did they earn a lot of money
• Are there other games that are going to launch at the same time?
• A budget
• How much to develop
• How long will it take?

Formal Design Document

• 2 sections
• Functional Specification
• Technical Specification

NDAs

• Non Disclosure Agreements
• Agreement not to steal ideas
• Don’t worry about signing, but read
• It’s very common

Camera Types

• Fixed Point
• Rotating
• Scrolling
• Movable
• Floating
• Tracking
• Pushable
• First Person

Rule #1: The Golden Rule

• Cinamatography: Convey plot or emotion
• What story want to tell
• What audiences want to see was before. User Center Design
• Gamatography: Both plot and emotion
• What players need to see
• Lensing: How the player sees the game and how the players

interprets what they see is a constant

• The Golden Rule of good gamatography: If your camera doesn’t help

the player play then design one that does.

Rule #2: Surrounding Space

• The game world is what gets most of the play brain’s attention
• The surrounding space of an action game is usually the immediate

area surrounding the character plus a cone extending out from its front

• For example, Super Mario, racing games.
• Rule: Make sure that the camera can always see the surrounding

space

Rule #3: How Much Agency?

• Moving perspective is a part of the play experience
• Any difficulties?
• First time player?
• People who got easily disoriented? (FOV)
• Expert players?
• Rule: Know your audience’s tolerance for camera control

Rule #4: Distance to Action

• Depth estimation is a lot harder in a 3D game environment. Especially

when the objects is moving toward or away from you.

• 2D games usually won’t have this issue
• If the main action is far away, like first person shooting games, aim is

more important

• If it is close-up games, like fighting, the ability to judge close distances

matters more.

• If the players need the information, be able to see the whole field is

vital

• Rule: Compensate for distance to action

Rule #5: Light The Way

• Human: 170 degrees of horizontal and 100 degrees of vertical vision
• A screen: 100 degrees of horizontal and 50 degrees of vertical
• A game: A world framed by the borders
• Easier to blindside players
• Rule: The camera and lighting need to lead rather than follow
• Cinema Examples
• Insanely Twisted Shadow

Rule #6: Transitions

• Modern games commonly use more than one type of camera.
• The complex part is managing the transitions.
• Cinema often uses cuts, however games are usually better served with

movement rather than cutting because cuts during play are disorienting.

• Sometimes movement transitions won’t work. When passing through a

doorway in third person action games. The game would have to pause for more than a second or move the camera through a wall. Neither is good, so the camera just cuts instead, but try fade out and fade in

• Preserve the direction to reduce the disorientation from a cut.
• Rule: Always ground your transition.

Ultimate Goal

• Fell natural!
• Robust and consistent through the whole game
• Predictable
• Gamatography’s job is to let players play and establish the emotional

connections on their own.

and an introduction to matrices

Coordinate Systems

The Local Coordinate System

(0, 0, 0)

The World SPACE

• The coordinate system of the virtual environment

(619, 10, 628)

(619, 10, 628)

Camera Space

Camera Space

(0, 0, -10)

The Big Picture

• How to we get from space to space?

? ?

The Big Picture

M ?

How to we get from space to space? For every model Have a (M)odel matrix! Transforms from object to world space

The Big Picture

Jeff Chastine 25

M V

How to we get from space to space? To put in camera space Have a (V)iew matrix Usually need only one of these

The Big Picture

M V MV

How to we get from space to space? The ModelView matrix Sometimes these are combined into one matrix Usually keep them separate for convenience

Matrix - What?

1.0 0.0 0.0 0.0 0.0 1.0 0.0 0.0 0.0 0.0 1.0 0.0 0.0 0.0 0.0 1.0

The Identity Matrix

A mathematical structure that can: Translate (a.k.a. move) Rotate Scale Usually a 4x4 array of values Idea: multiply each point by a matrix to get the new point Your graphics card eats matrices for breakfast

Back to The Big Picture

M

If you multiply a matrix by a matrix, you get a matrix! How might we make the model matrix?

Back to The Big Picture

M

Translation matrix T Rotation matrix R1 Rotation matrix R2 Scale matrix S

If you multiply a matrix by a matrix, you get a matrix! How might we make the model matrix?

Back to The Big Picture

Jeff Chastine 30

M

Translation matrix T Rotation matrix R1 Rotation matrix R2 Scale matrix S

T * R1 * R2 * S = M If you multiply a matrix by a matrix, you get a matrix! How might we make the model matrix?

Modeling and Animation For Game Design

CGDD 4003

Why Modeling for Games?

• 3D modeling for games is a whole different monster
• Movies VS Games
• Polygon budget
• Why?

Level of Detail (LOD)

• Different detail levels for a single asset

The Skeletal Hierarchy

(aka the “rig”)

• Based on the concept of bones
• Each bone has exactly one parent
• Each bone has a transform
• Not necessarily a matrix (later)
• How it differs from its parent
• If its transform is identity matrix
• Same translation
• Same rotation (orientation)
• The root bone has no parent (e.g. pelvis)
• Rotations/translations are relative to local coordinates
• There are also synthetic root bones (ground shadows)

Kinematics

• Forward kinematics
• Moving a parent bone moves the children
• Easy to program, hard to animate
• Inverse kinematics (IKs)
• Moving child bones affects parent bone
• Easier for animators
• Solve iteratively
• Need to draw this on the board…

Euler Angles

(pronounced “Oi-luh”)

• 3 angles to describe orientation around 3 axes
• Order of rotations is important!
• Two rotations can result in the same orientation
• Usually stored in a 3x3 matrix.
• Two similar rotations have similar values in matrices
• Linear blending will be ok
• Size is large

Enter the Quaternion

• Another way to represent rotations
• Great for interpolation (thus, common)
• Uses 4 components (x, y, z, w)
• In general, (x, y, z) is the axis of rotation
• Length of (x, y, z) is sine of half the rotation angle
• w is the cosine of half the rotation angle (20° vs. 340°)

Animation Storage

• How big?
• Store 4x3 matrix for each bone, for each frame
• 30 fps, 50 bones
• 5 major characters, 100 animations each
• 15 minor characters, 20 animations each
• Animation lasts 4 seconds
• 𝑇𝑞𝑏𝑑𝑓 = 30𝑔𝑞𝑡 ∙ 4𝑡𝑓𝑑 ∙ 50𝑐𝑝𝑜𝑓𝑡 ∙ 4 ∙ 3 ∙ 4 ∙

5 ∙ 100 + 15 ∙ 20 = 220𝑁𝐶

• Xbox 360 has 512MB and Wii has 88MB
• The animation system takes up nearly ¼ of all memory?
• Can we do better?

Animation Storage

• Eliminate unnecessary data
• Most bones don’t need shear, scaling
• Some don’t need translation (hips, knees, elbows)
• Some characters hardly move!
• Space
• Scaling, Shearing,

Translation = 3

• Rotation

(quaternions) = 4

T.K. Baha from Borderlands

Animation Storage

• Assume:
• 10% of bones shear
• 20% of bones scale
• 50% have translation
• 90% have orientation
• One bone / frame is now:

4𝑐𝑧𝑢𝑓𝑡 ∙ 0.1 ∙ 3 + 0.2 ∙ 3 + 0.5 ∙ 3 + 0.9 ∙ 4 = 24 𝑐𝑧𝑢𝑓𝑡

• vs. the 48 bytes previously
• However, we have to reconstruct the 4x3 matrix for each bone

now!

Note: We’re now at 110MB, still 5 times bigger than budget for Wii. Can we do better?

Animation Storage

• Obvious candidate: don’t use 30 fps!
• Keyframing: set important poses and then interpolate (old animation

technique)

• On “average”, 10 keyframes per second
• 1/3 the space = 37MB!
• Keyframing problems:
• Loses data

Note: we’re at 37MB. Can we do better?

Animation Storage

• Linear interpolation between frames
• 𝑠𝑓𝑡𝑣𝑚𝑢 =

1 − 𝑢 ∙ 𝐺

1 + (𝑢 ∙ 𝐺 2))

• 𝑢 is time and 𝐺

1and 𝐺 2are frames

• Higher Order Interpolation
• Use Bezier (pronounced “Beh-zee-ay”)
• Cubic function, with continuity (C0, C1, C2…)
• Define controls at endpoints (𝑈

1and 𝑈2)

• Can drop the memory usage by ¼

AI for Game Design

What is AI for Games?

• Emulating the behavior of other players or the entities.
• The key is simulation!
• AI for games is more “artificial” and less “intelligence”
• Because “intelligence” in games is the hardest part
• *Winning is not always correct!

Tradition AI vs Game AI

• Traditional AI
• Real intelligence
• Machine learning
• Interact socially emotions
• Game AI
• Above and beyond the requirements of a piece of entertainment software
• Doesn’t need to learn about anything beyond the scope of gameplay
• Simulate intelligent behavior
• *Provide a believable challenge!

Decision Making

• This is the core concept behind AI
• When to execute?
• How to interact with the players?
• How to implement?

Rules-Based Systems

• A set of preset behaviors is used to determine the behavior of game

entities.

• Pac-Man AI

Finite State Machines as AI

Adaptive AI

• This is the KEY and most difficulty part for games
• Before, the AI systems are for predefined events of games
• For more variability and a better, more dynamic adversary
• Fighting games, strategy games, racing games, etc.

Prediction

• Pattern Recognition
• Randomize

AI Cases for Games

• Path Finding & Perceptions
• Tactical & Strategic AI
• Using Threading to Apply AI

How AI Perceives?

• What if the AI agents need to know what’s going on around them?
• Complicated! Still a hot research topic
• How do we know this world?
• Vision, sound, smell, taste, touch
• Simulation!

Sight

• The most basic level
• Everything is known – easier than the real world
• Calculate the information between two objects:
• Distance
• Angle
• Collision Detection
• Unity – Navigation Mesh

Other Senses

• Because everything is known in the VE, other senses are used less,

but still useful to enhance the experiences

• More research opportunities here:
• Sound
• Smell
• Radar
• Haptic
• Taste

CGDD 4003

Shaders

Shaders

• Scary!
• Weird terminology
• Primitive assembly
• Rasterization
• Zwrite
• Cull
• Stencil
• Math and Data
• Vertices, Fragments
• Vectors, Matrices, Textures
• Cross and Dot product
• Matrix multiplication

Shaders

• What is a shader?
• It is a small program that runs on the GPU
• Usually written in a high level shader language (e.g. GLSL)
• Produce images
• Input: Mesh, Material Data, Lighting Data, and etc.
• common shaders:
• Vertex Shader: executes once for every vertex
• Fragment Shader: executes one for every fragment

(potential pixel)

Shaders in the Graphics Pipeline

OpenGL (application software) Fragment Shader Vertex Shader

Shaders in the Graphics Pipeline

Vertex Shader Applications

• Moving vertices
• Transformations
• Morphing
• Wave motion (e.g., water)
• Fractals
• Lighting
• More realistic models
• Cartoon shaders

Fragment Shader Applications

Per fragment lighting calculations

per vertex lighting per fragment lighting

Fragment Shader Applications

Texture mapping

smooth shading environment mapping bump mapping

Linear Interpolation

• Math
• Bezier: 2 points, 3 points
• Code