A virtual Environment for providing sensory input to networks, posibly with feedback on the position of the observer. A rat can be moved with the mouse, with the arrow keys on the keybord, randomly or it can be driven by some other component. The output is the contents of the visual field of the rat and measures of the proximity of markers defined in the environment.
The Environment consists of closed shapes, line segments and marked points. The latter are round but of variable diameter. The user interface options are quite limited as yet, and come from the Labelled drawing editor. Closed and open line segments can be dragged from the bar at the top. To change their size, click any point, without dragging it, and then drag one of the green control points. Individual points can be dragged, with the exception of the first point on any line which moves the whole line.
The two markers at the top right are for points (round) and lines (square). The line marker can be attached to any point on a line, and sets the properties of that line. Specifically this sets its CcmbColor and whether the rat can cross the line (the fpref and width fields are unused). The point marker defines a disk of a specified width in the environment. Such points are visible to the rat, and can also be sensed by their proximity.
The rat field below the diagram, sets a rat to inhabit the Environment. Rats are characterized by size, viewing angle, step size, the range at which they sense proximity to markers, and other fields to control behavior under random walk mode. The rat can be moved with the mouse by dragging the point in the center and turned by dragging the nose or tail. It can also be moved with the keyboard arrow keys: up and down for forward and reverse; left and right to turn. The response to these keys depends on the mode field. In continuous mode, the mouse carries on moving until anothe key is pressed (use the spacebar to stop it entirely), whereas in step mode each key press causes one step.
The top of the window shows the proximity to makers and the current visual field of the rat. Any markers within the range field of the rat appear as solid bars at the top. The visual field shows the colours of all lines and regions within the viewing angle. The background is black, and unlabelled lines appear red. This is calculated by discretizing the field into npixel bins of equal angle as specified in the rat object and then Z-buffering all lines and segments in the drawing.
Initial specifications requested and funded by Mike Hasselmo -- grant numbers NSF IBN 9996177, NIH MH 60013 and NIH MH 61492