Interactive Cinematography

1
(Interactive) Cinematography

• Ref Chap. 16 (Core Techniques and Algorithms in
  Game Programming)

2
Introduction

• Placing the camera is extremely important from a
  narrative standpoint
• Helps to convey the story
• interesting games spoiled by bad camera angles

3
FPS

• Camera movement 4 DOF (x,y,z,yaw)
• Pitch (sometimes) strafing (moving sideways)
• E.g., keyboard (playerpos) mouse (orientation)
• Adding inertia to camera for increased realism
• implement control on acceleration (not velocity)
• opengl implementation

4
FPS Control
Use mouse to change direction
5
Implementing FPS
6
Inertia Camera

• Keyboard still position control
• Mouse drag
• Speed proportional to torque
• Each jerk represent an impulsive torque
• Need friction to stop
• Time-based motion by Euler integration

7
Mouse Movement

• Use glutPassiveMotionFunc
• Detect moving direction
• Detect moving speed
• Related API calls
• glutPassiveMotionFunc, glutSetCursor,
  glutWarpPointer
• Ref Refhttp//www.gamedev.net/community/forums/t
  opic.asp?topic_id202516

• Issues
• Hide mouse cursor
• Lock mouse focus

8
Flight Simulation

• Placing virtual camera inside a cockpit
• Complexity
• 6 DOF
• Careful for upside-down motion (flying a loop)
• Euler angles gimbal lock problem
• Use quaternion how? Code

9
Third-person Camera

• Not to occlude the enemy
• Problem rotating will cause the camera to define
  large arcs (motion sickness)
• Solution inertia camera
• Interpolate orientation quaternion

• Problem camera colliding with level geometry
• Solution transparent wall between
• Change camera location move up (lower roof),
  sideways (corner), in front of the player

10
Third Person Camera
11
Cinematic Cameras
12
Camera Styles

• Fixed camera
• Dolly cameras
• Crane cameras
• Steadycams
• Implement a real-time algorithm that selects the
  best camera according to heuristics (e.g., the
  one closest to player)

13
Placement Algorithms

• Basic rules
• show everything relevant to the scene
• Should be placed so obstruction between relevant
  information does not occur
• Aimed at a point of interest
• Main character, other character in the vicinity,
  pickable items closer than a threshold, objects
  relevant to game play (e.g., obstacle)

14
Ex Camera Placement
Dolly
Pan
Fixed
Dolly
Pan
15
Agent-based Approach

• AI techniques (rule-based system) to model the
  decision process used by our virtual
  cinematographer in order to call the best
  possible shot