The next three components are maybe less criticial than the previous two, but it is important to describe them, as they will come into play not matter what.
Position : the emitter has position. That’s pretty much it.
Moving / static : the emitter can be stuck to a position, or can move around, either in a fixed direction or in freeform
Can it be captured by bubbles? : self-explanatory
Is it captured by a bubble? : idem
Size : again, this seems pretty obvious.
Direction : if the ripple created by the emitter is not 360 degrees wide, then the emitter should have a visible direction that is going to hint in which way the ripples will be heading
Synthetic sound : each emitter will have a sound that it will emit. This sound can be musical or a sound effect designed by the team or the sound of a bubble that has been converted.
On/off : some emitters will be on all the time, but others will have to be activated or de-activated by the player
Rythm : does the emitter emit continuously or only in little bursts (if so, at which rate?)
Position : the position of the avatar
Size : the avatar will have a size, probably the same throughout the game
Direction : the avatar must have a visible forward direction, because that’s where the bubble will be spawned from.
Color and alpha : we should put this variable in, as it may prove useful later in the development, if we want to give special properties to the avatar, which he will pass to the bubbles he’ll make.
Velocity : the speed at which the avatar travels after the player’s input
Strength : because we want the avatar to be essentially powerless and useless, its strength would be close to zero, in a way that any ripple would affect him.
ENVIRONMENT (mostly walls)
Camera : the camera will be centered on the player’s avatar to enhance the feeling of exploration as it travels through the contiguous environments. However, it should be far enough in order to be able to get a good idea of the surroundings and manipulate bubbles even after a great distance.
Fluid : if we decide to go with fluid simulations, we’ll have to take into account its properties
Color and alpha : again, this is the idea of giving special properties to walls and obstacles
Wall properties : additionnaly to color, the walls could have visibles traits that would give them special properties (such as letting bubbles bounce)