Yingcai Xiao Game Development Interactive Animation

Video Game Interactive Animation: user-> interface (look) -> action (feel) -> feedback (A/V, haptic)

Video Game User Controller Display Game (Software)

Video Game Input Device Driver Display Device Driver (GDI) Display Device Driver (GDI) Game (Software)

Game Programming Components The Gang of Four (G4) for Interactive Animation 1.Controller (Input) 2.Game Objects (Geometry and Attributes) 3.Dynamics (Key Frame Animation) 4.Event-driven Programming (EDP: connects inputs to animation scripts) The Gang of Four (G4) for Interactive Animation 1.Controller (Input) 2.Game Objects (Geometry and Attributes) 3.Dynamics (Key Frame Animation) 4.Event-driven Programming (EDP: connects inputs to animation scripts)

Game controllers: input devices The evolution of input devices: CL (Commend Line Input) GUI (Graphical User Interface) NUI (Natural Interface) The evolution of input devices: CL (Commend Line Input) GUI (Graphical User Interface) NUI (Natural Interface)

Animation Animation: any change that has a visual effect. Motion Dynamics: movements (geometry change) Update Dynamics: attribute change (color, texture, …) Others: camera position, lighting, rendering techniques, … Animation: any change that has a visual effect. Motion Dynamics: movements (geometry change) Update Dynamics: attribute change (color, texture, …) Others: camera position, lighting, rendering techniques, …

Key-frame Animation Defining key-frames Inbetweening with interpolations: Lerping (linear interpolation) parabola interpolation Defining key-frames Inbetweening with interpolations: Lerping (linear interpolation) parabola interpolation

Key-frame Animation

Neighborhood skeletons: define interpolated shapes

Graphical languages P-curves (parametric representation of motion)

Animation Control Explicit: animator provides a description of everything that occurs in the animation. Tracking live action. Procedural: movement computed by a procedure. Actors (Object-oriented high-level procedural control) Kinematics: positions and velocities of points. Dynamics: physical laws that govern kinematics. Physically based: cloth draping, plastics bending, … Constraint-based: constraint movements. Explicit: animator provides a description of everything that occurs in the animation. Tracking live action. Procedural: movement computed by a procedure. Actors (Object-oriented high-level procedural control) Kinematics: positions and velocities of points. Dynamics: physical laws that govern kinematics. Physically based: cloth draping, plastics bending, … Constraint-based: constraint movements.

Double Buffering Why? To reduce flickering How? Draw to the invisible back buffer Copy to the visible front buffer. (Btblt)==>very fast with HW assistance Why? To reduce flickering How? Draw to the invisible back buffer Copy to the visible front buffer. (Btblt)==>very fast with HW assistance

Double Buffering – Pseudo Code void Draw() { useCanvas(bbfr); DrawObjects(); useCanvas(SCREEN_CANVAS); copyPixel(bbfr, viewing-rectagle); } void Draw() { useCanvas(bbfr); DrawObjects(); useCanvas(SCREEN_CANVAS); copyPixel(bbfr, viewing-rectagle); }

Separation of Development Tasks The Gang of Four (G4) for Interactive Animation 1.Controller (Input) 2.Game Objects (Geometry and Attributes) 3.Dynamics (Key Frame Animation) 4.Event-driven Programming (EDP: connects inputs to animation scripts) The Gang of Four (G4) for Interactive Animation 1.Controller (Input) 2.Game Objects (Geometry and Attributes) 3.Dynamics (Key Frame Animation) 4.Event-driven Programming (EDP: connects inputs to animation scripts)

Two Aspects of Game Development Look + Feel Look: Appearance Game Objects (Geometry and Attributes) can be created by artists though a visual interface like Blender and Maya or download prebuilt ones online (e.g. Look + Feel Look: Appearance Game Objects (Geometry and Attributes) can be created by artists though a visual interface like Blender and Maya or download prebuilt ones online (e.g.

Two Aspects of Game Development Feel: Controlled Animation animation scripts connected to input events via EDP implemented by programmers though a programming language or a visual interface like Unity3D Feel: Controlled Animation animation scripts connected to input events via EDP implemented by programmers though a programming language or a visual interface like Unity3D

Graphics HW and SW Layers ApplicationGameGraphics SW Application Initialization Utility Game IDE Application Library OS GUI API Event Loop Game Engine OS EQ InterfaceGraphics LibraryGraphics Engine Event QueueGDI OS GPU Graphics HW Graphics Card