MOUSE PLAYHOUSE (VR)
Grid System
The pickupable objects on the table are designed to snap their positions and conform to a grid when placed on the table (this mechanic is further explained in Pickupable Object Mechanics). Every time a player picks up an object from the table, this grid appears when the player's motion controllers are close to the table and shows all the possible locations the object can snap its position to when let go by the player.
The tables have a bounding volume around them that are used to determine the shape of the grid and the number of grid squares to generate. Each grid square is a single entity and multiple of them are generated at the start of each level. This is so that a grid can be formed according to the shape of the table in each level as some levels contain U-shaped tables and L-shaped tables.
The grid is initially hidden and stays hidden until an object is picked up. Even after an object is picked up, the entire grid is not shown. The motion controllers have a sphere of visibility around them that determine how much of the grid should be visible to the player. The parts of the grid that are within a certain distance from each motion controller, i.e. closer than the radius of the sphere, are shown.
Pickupable Object Mechanics
The table puzzles in each level involve picking up objects from the table and arranging them in order to guide the mouse (or mice) to the cheese. Picking up objects is done by holding down the trigger on the motion controllers while the controller is overlapping with an object. Releasing the trigger releases the object from the controller. Only one pickupable can be picked up by each controller.
There are two types of pickupables used for the puzzles: the wedge pickupable and the cube pickupable. Both the wedge and the cube are identifiable by their blue colour scheme and are highlighted with a blue border whenever they are able to be picked up. Pickupables underneath other pickupables cannot be picked up and do not have a blue border until the top pickupable is removed.
Other pickupables can be placed on top of cubes but they cannot be placed on top of wedges. Two wedges can be combined together to form a cube and this acts as a single cube pickupable and other pickupables can be placed on top of this combination. Removing one of the wedges reverts it to a single wedge again and pickupables cannot be placed on top anymore. The wedges cannot be removed from the combination while a pickupable is on top of them.
Each pickupable has four possible states: Free, Held, Rigid and Snapping. Whenever a pickupable is free-falling through the air or at rest outside the bounds of the table, it is considered to be in free state. When it is held by the player, it is in held state. Rigid state is when the object is at rest on the table.
Snapping state is a special intermediate state between free state and rigid state. When a pickupable is dropped or placed on the table and comes to rest at an arbitrary position and rotation, it goes into the snapping state and snaps, i.e. its position and rotation is rounded to the nearest value in order to conform to the grid, before going to the rigid state.
For each pickupable that is held, a ghost version of the pickupable appears when the held object gets close to the table. The ghost predicts the snapped position and rotation of the object in order to give the player an idea as to where the object will snap to when it is released. A red ghost indicates invalidity and a blue ghost indicates validity. If the player releases in an invalid position, the object will snap back to its last valid position. Only valid moves count as moves in the move counter.
AI Movement
The mice and meowbots in the game are the only two characters and AI characters that move and react to the obstacles on the table and path accordingly. Both the mice and meowbots (hereafter collectively referred to as character pawns) have very similar behaviours and are therefore derived from the same base character pawn.
The character pawns move according to the grid and moving from one grid space to the next is considered as a single step of movement. Whenever a pickupable object is picked up, the mice complete their current step and stop in their current grid spaces and do not start moving until all pickupables are snapped on the table. The meowbots are initially stationary and don't start moving until the first pickupable is picked up. Then onward, they are always moving, unlike the mice.
Most of the objects on the table, pickupable and non-pickupable, are shaped as cubes and wedges and the character pawns react accordingly with these types of objects. The characters pawns move normally on flat surfaces such as the surface of the table and the tops of cubic objects. When moving, if the characters are obstructed in the next grid space, such as a cube or the flat side of a wedge or similar objects, they turn around and start moving in the opposite direction.
When faced with the diagonal side of a wedge in the next grid space, if the wedge is oriented as a ramp, the character pawns move up and down the ramp to the next higher or lower level. If the wedge is oriented on its side, then the character pawns will go into the space of the wedge and turn 90° in the direction the wedge is facing before moving in that direction.
For special objects such as the fans, the traps and the dominoes, the character pawns have special behaviours. The fans have air blowing out from them and have an area of effect of one grid space in front of them. Both character pawns, when they enter that grid space, are pushed to the next grid space in the fan's air direction without changing their own direction.
When the mice enter a space with a trap, they immediately play their 'feign death' animation which triggers the resetting of the level. And when the meowbots enter a space with a trap, they play their deactivation animation and stay trapped for the remainder of the level.
The dominoes are a unique kind of obstacles which can only be triggered by a character pawn hitting them. When the character pawns hit them from the side, the dominoes wobble but do not fall. But when they hit the dominoes from either of the ends, the dominoes fall and clear the character's path. The characters reverse their directions when they hit the dominoes from all sides but can move over on top of the dominoes once they fall.