The Benefits of Guidelines. Elimination of hype Clarity and certainty Ease of drafting schedules and test plans Varying from the guidelines

Transcription

1 The Benefits of Guidelines Elimination of hype Clarity and certainty Ease of drafting schedules and test plans Varying from the guidelines

2 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

3 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

4 General Concept Docs Story Characters Environment/Level Gameplay Art Description Sound User Interface and Controls

5 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?

6 Formal Design Document 2 sections Functional Specification Technical Specification

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

8 Camera Types Fixed Point Rotating Scrolling Movable Floating Tracking Pushable First Person

9 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.

10 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

11 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

12 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

13 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

14 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.

15 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.

16 Coordinate Systems and an introduction to matrices

17 The Local Coordinate System (0, 0, 0)

18 The World SPACE The coordinate system of the virtual environment (619, 10, 628)

19 (619, 10, 628)

20 Camera Space

21 Camera Space (0, 0, -10)

22 The Big Picture?? How to we get from space to space?

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

24 The Big Picture How to we get from space to space? To put in camera space Have a (V)iew matrix Usually need only one of these M V Jeff Chastine 24

25 The Big Picture How to we get from space to space? The ModelView matrix Sometimes these are combined into one matrix Usually keep them separate for convenience M V MV

26 Matrix - What? 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 The Identity Matrix

27 Back to The Big Picture If you multiply a matrix by a matrix, you get a matrix! How might we make the model matrix? M

28 Back to The Big Picture If you multiply a matrix by a matrix, you get a matrix! How might we make the model matrix? Translation matrix T Rotation matrix R 1 Rotation matrix R 2 Scale matrix S M

29 Back to The Big Picture If you multiply a matrix by a matrix, you get a matrix! How might we make the model matrix? Translation matrix T Rotation matrix R 1 Rotation matrix R 2 Scale matrix S M T * R 1 * R 2 * S = M Jeff Chastine 29

30 Modeling and Animation For Game Design CGDD 4003

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

32

33 Level of Detail (LOD) Different detail levels for a single asset

34 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)

35 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

36 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

37 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 )

38 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 SSSSSSSSSS = 30ffffff 4ssssss 50bbbbbbbbbb = 220MMMM Xbox 360 has 512MB and Wii has 88MB The animation system takes up nearly ¼ of all memory? Can we do better?

39 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

40 Animation Storage Assume: 10% of bones shear 20% of bones scale 50% have translation 90% have orientation One bone / frame is now: 4bbbbbbbbbb = 24 bbbbbbbbbb 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?

41 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?

42 Animation Storage Linear interpolation between frames rrrrrrrrrrrr = 1 tt FF 1 + (tt FF 2 )) tt is time and FF 1 and FF 2 are frames Higher Order Interpolation Use Bezier (pronounced Beh-zee-ay ) Cubic function, with continuity (C0, C1, C2 ) Define controls at endpoints (TT 1 and TT 2 ) Can drop the memory usage by ¼

43 AI for Game Design

44 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!

45 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!

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

47 Rules-Based Systems A set of preset behaviors is used to determine the behavior of game entities. Pac-Man AI

48 Finite State Machines as AI

49 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.

50 Prediction Pattern Recognition Randomize

51 AI Cases for Games Path Finding & Perceptions Tactical & Strategic AI Using Threading to Apply AI

52 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!

53 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

54 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

55 Shaders CGDD 4003

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

57 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)

58 Shaders in the Graphics Pipeline Vertex Shader Fragment Shader OpenGL (application software)

59 Shaders in the Graphics Pipeline

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

61 Fragment Shader Applications Per fragment lighting calculations per vertex lighting per fragment lighting

62 Fragment Shader Applications Texture mapping smooth shading environment mapping bump mapping

63 Linear Interpolation Math Bezier: 2 points, 3 points Code