CAMERA CONTROL

1. CAMERA CONTROL Ashira Khere Jake Thompson Shiro Sakurai

2. Camera Control • Cameras provide useful interfaces to play games. • Allows communication of visual goals so that players know what happens in the game. • Gives audience certain impression of a subject or its surroundings. • Like motion picture, camera techniques can enhance the audience’s experience.

3. Camera Control • Most of current computer games use a fixed point of view or a first person’s view. • Easy to design and control, however, offering only one view for the player to see the scene. • 3rd person adventure games have moveable cameras. • These cameras are fixed on the main character at a distance that encompasses most of the actions. • Main Problem: • Game developers are not in control of character placement, so the camera is poorly implemented, and usually dragged behind the character.

4. First Person Camera • camera's position is fixed relative to (the inside/front of) the player's transparent head • if you render a second view of the player as a reflection in a mirror, remember to make the head opaque again • view vector always points out of the front of the player's skull • up vector should be permanently fixed to point out of the top of the player's skull • if player can walk on walls or ceilings, this makes sure the camera automatically rolls appropriately

5. First Person Camera

6. FPC Controls • left and right don't turn the camera, they turn the player in place, and the camera follows because it is fixed • if left/right did turn the camera, then moving "forward" goes in a different direction than the facing • up and down change the angle measure between the player character's skull and their spine • the range of the angle shouldn't be wider than 180°

7. FPC Controls • zoom in and out by resizing the dimensions of the projection window: smaller for zooming in, larger for zooming out • if you don't put caps on either end of the zoom range, then zooming in too far will flip the window horizontally and vertically, and zooming out too far will make the window clip through walls/floors/ceilings • never try to implement zooming by varying 'dnear': anything that walks between the camera and the player will be invisible, and the player will be able to zoom through walls • up/down/left/right can be bound to the mouse (a.k.a. free look or mouselook), to an analog stick, to buttons (the least ideal choice), etc.

8. Third Person Camera & Control • halo camera controls: camera moves in a circle around a point above the player's head • two length measures and one angle measure • in general considered not as good as:

9. Third Person Camera & Control • spherical camera controls: camera can be anywhere in space that's a fixed distance from the lookat point (hence the word "sphere") • one length measure and two angle measures • left/right move the camera's longitude around a "circle of latitude", up/down change the latitude (ranges between +90° and -90°)

10. Third Person Camera & Control • one of the drawbacks inherent in 3rd-person cameras is handling camera/wall collision. Allowing the camera to simply pass with impunity interferes with suspension of disbelief, and making the camera bounce off leads to the all-too-common problem of the camera "getting trapped," i.e. the player must fight against the camera controls to be able to see what they want

11. Second Person Camera • from enemy's point of view, looking at the player • has been used as a gimmick in a few game boss fights • perhaps not a good idea for general use: player has no camera control, moving behind cover occludes player's view of self, enemy moving around the room may disorient the player

12. Cinematography in Games • Cinematography is the art of film making. • The action in the game is followed not by one camera, but by a team of cameramen who watch the action and always try to show it from the best angle. • Cinematography can be used for: • Adding dramatic emphasis wherever necessary • Clarify unclear events in a game’s plot • Ensure that the player does not become disoriented • Evoke emotional responses in the same way as a motion picture does.

13. Camera types • Fixed cameras • fixed to the ground using a tripod or stable base • can use tilting, panning, or zooming • Dolly cameras • moving cameras placed on top of wheeled structures • Crane cameras • perched on top of large arms so they can perform wide arcs on the set • some cranes can be mounted on top of dollies • Steadycams • portable camera that is usually attached to the chest of an operator.

14. Type of Shot • Dramatic shot focus on character and his attitude • extreme close-up • medium close-up • full close-up • wide close-up • close shot • medium close shot • Informational shot • medium shot • medium full shot • full shot • long shot

15. Implementation Overview Cinematography camera controls can be implement following steps: • Define abstract camera class. • Implement specific camera types delivered from abstract camera class. • Place cameras into the scene using • Implement a real-time AI module to select the best camera and shot. • The real-time camera AI module is executed once every few game cycle and the results should be interpolated.

16. Implementing Camera Types class Camera { public: virtual float getDistance(Position target); virtual void render(); }; class FixedCamera : public Camera { private: Position location; public: virtual float getDistance(Position target) { return target.distance(location); } virtual void render(); }; class DollyCamera : public Camera { private: Path rail; public: virtual float getDistance(Position target) { . } virtual void render(); }; • Define abstract camera class. • Implement specific camera types derivered from abstract camera class. class CraneCamera : public Camera { private: float armSize; Position location: public: virtual float getDistance(Position target) { . . } virtual void render(); } class Steadycam public Camera { private: Position curPosition; public: virtual float getDistance(Position target) { . . } virtual void render(); };

17. Place cameras • Place cameras using contents creation tool, much like a movie director would do.

18. Selecting the Best Shot • Basic Rules • The camera should show everything relevant to the scene. • The camera should be placed so obstruction between relevant information does not occur. • The camera should be aimed at a point of interest in the scene. • Mathematical Approach • Selecting camera target • Selecting relevant information • Selecting view angles • Agent Based Approach

19. Selecting Camera Target • Need to consider case-by-case situations. • General case • Target player • Approaching Monster • Line between player and Monster • Group Situation (conversation between several peer) • Center of the scene to make sure everyone can fit on the screen. • Camera moving and even switching between different cameras should be kept to a strict minimum.

20. Select Relevant Information • Find relevant information • The main character • Other characters in the vicinity • Pickable items closer than a set • Objects relevant to the gameplay, such as an obstacle • Compute adequate camera frustum so everything fit in view volume Select View Angle • Compute the best view direction as the one that generates fewer occlusion in the scene.

21. Agent Based Approach • Cinematography camera is easily be implemented by a rule-driven camera agent. If the position of the player is not covered by the current selected camera select a camera which covers current position Move camera to closest position Set camera target to the player When npc is closer and npc is enemy Select destination = npc Select origin = overhead from player Otherwise select destination = ahead of player select origin = overhead from player