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Documentation Table of Contents

The Syzygy VR framework applications tend to work best with a VR style interface, namely six-degree-of-freedom (6DOF) head tracking and some kind of joystick type input device with another 6DOF sensor attached. However, such external input devices are inaccessible when running programs in Standalone Mode and may in any case be unavailable. As a workaround, Syzygy includes support for a simulator interface that can operate the included (and your own) programs from a desktop using mouse and keyboard.

When running in standalone mode the simulator normally appears as an overlay in the lower-right corner of the window. In cluster mode it is a separate program, inputsimulator; you would normally use it in cluster mode by specifying it as the primary input for a virtual computer.

The input simulator window shows a view from behind into a 10-foot cubical space (reminiscent of the inside of our CUBE). A wireframe sphere in the center represents the subject's head (initially facing away from us, although the view has been rotated in this figure, see mode 7 below).

The blue rectangle to the lower right of the display containing several numbered red circles represents a set of virtual buttons on a wand (a tracked, hand-held input device). The input simulator sends data to the application specifying the position and orientation of the head and the wand and the state of the wand's virtual buttons. By default, the blue rectangle contains circles representing eight buttons, arranged in two columns of four buttons; the number of virtual buttons can be changed by setting the parameter SZG_INPUTSIM/number_button_events to the desired number in the Syzygy database. The two columns correspond to the actual buttons on your real mouse, with the left and right real mouse buttons corresponding to the left and right columns of virtual buttons. One row of buttons (initially the bottom one, indicated by the small right circle next to virtual button #0) is active at any time; you change the active row by pressing the space key. Pressing a real mouse button (when the simulator is in an appropriate mode, see below) presses the corresponding virtual wand button in the currently-active row.

If a middle mouse button exists and the user presses it, the layout of the virtual wand buttons changes to three columns, as shown here. The left, middle, and right real mouse buttons map to the columns in the obvious way. You can set the simulator to initially assume a three-button mouse by setting the parameter SZG_INPUTSIM/mouse_buttons in the Syzygy database to the string 0/1/2. (The value for this parameter must contain 0 and 2, corresponding to the standard left and right buttons; if you have an input device with more than three buttons, you can try adding them as well. No guarantees that they'll be useable, though).

The green circle inside a white square below the button display represents a joystick. The position of the green circle inside the square (initially centered) represents the angle at which the joystick is held. In the correct simulator mode (see below), dragging the mouse moves the joystick.

The simulator interface has several modes that are selected by the number keys 1-7 on the main keyboard (i.e. the numeric keypad probably won't work).

1. Translate the head. Mousing with the left button held down moves head left/right and up/down. Mouse with the right button down moves head left/right and forwards/backwards.
2. Rotate head. Mousing with the left button down rotates head around the vertical axis. Mouse with the right button down rotates the head around the axis through the ears. PLEASE NOTE: Whether or not head rotation noticeably affects the images displayed by your application depends on how you've configured the viewing camera. In Syzygy, the default VR camera is head-mounted. In this case, rotating the head will rotate the field of view in the virtual world. On the other hand, if a fixed-screen VR camera is used (as would be desirable for a CAVE environment), rotating the head will cause only a small change in the displayed image.
3. Translate wand: Mousing with the left button down translates the wand left/right and up/down. Mousing with the right button down translates the wand left/right and into/out of the screen.
4. Translate wand & use buttons: Mouse movement (with no buttons pressed) translates the wand left/right and forwards/backwards. Pressing mouse buttons activates the device buttons.
5. Rotate the wand & use buttons: Mouse movement (no buttons pressed) causes the wand to rotate. Pressing buttons activates the mouse buttons.
6. Use the joystick: While a mouse button is held down, draggin the mouse moves the joystick.
7. Rotate the world: When a mouse button is held down, the view rotates around the vertical axis.

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