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MBOX® USER MANUAL
Note: In the case of controls where each layer may not need a different/unique value (e.g., positional data) the Stride
value should remain at 0. For controls like opacity that might need a unique value for each screen object for each layer,
the stride setting becomes very useful.
Step 12. Because some controls need to have a per-layer value and some do not, this leaves several options on
how to patch everything. Every control could have a unique address for control on every layer. But this
would require the use of more control channels and might require the source of control to have to send the
same values on more than one channel at the same time. One alternative is to use the stride setting (where
applicable), and to use the same address for controls that need to receive the same data. This cuts down
on repeated data, but leaves empty channels in the patch. The other alternative is to patch all unique control
channels sequentially (at the beginning of the universe) before any controls that require a stride setting, and
then patch the per-layer controls using a stride setting.
a. Data Format Pop-up: Sets the range and default value of incoming control data. As with typical
xtures, 8-bit data uses one channel (0 - 255), 16-bit uses two (0 - 65535). 32-bit signed data uses four
(-2,147,483,648 - 2,147,483,648) for extra accuracy with moving scenery.
1) In the case of the 8-bit controls, “unsigned” relates to a control with a range of 0-255 and a default that
is one end of that range (usually 0). “128” relates to a control with a range of 0-255 and a default of
128, and which varies above and below the default. “127” is like “128” but with a default of 127.
2) In the case of the 16-bit controls, “unsigned” is as with the 8-bit version noted above, but with a range
of 0-65535. “Offset” relates to a control like the 128/127 varieties of the 8-bit controls, with a default
at halfway: 32767.
3) And nally, the 32-bit signed control has a very large range that is both negative and positive. 32-bit
signed controls are generally reserved for positional feedback from very accurate scenic encoders.
The large range allows the control to be extremely accurate, receiving actual encoder counts in many
cases.
b. Control Type Pop-up: The parameter of the screen that is to be controlled is selected here - position,
texture position, rotation, etc. Refer to “Screen Object Control Types” on page 138 for more details on
the control types.
c. Scale/Counts Pop-up: Switches between the two methods of scaling incoming control data when it is
applied it to a control.
1) For example, if Mbox is receiving a 16-bit offset value for the X Position parameter, but only ever needs
to move a screen object 100 pixels left or right, then it may make sense relate the full range of 0-65535
(65536 steps) to a range of 100px to the left to 100px to the right (-100 to +100). Since the total range
of movement is 200 pixels, the Scale value would end up being 200/65536 = 0.00305176.
2) As an alternative to scale, counts (typically used for linear position controls) equate to the number of
control data steps (i.e. counts) the should be received by Mbox in order to cause one pixel of total
travel. With the above example, since 65536 steps of data will move the screen object 200 pixels, the
Counts value ends up being 65536/200 = 327.68
3) The two methods are just the same information presented in a different ways, one is the reciprocal of
the other: 200px/65535counts = 0.00305176 (scale = pixels per count) and 65535counts/200pixel =
327.68 (counts = counts per pixel). 1/0.00305176 = 327.68.
Note: The sign (+ or -) of the scale/counts value is be used to invert the parameter’s direction of adjustment relative to
the incoming data.
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