PRG Mbox - Page 137

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MBOX® USER MANUAL
At this point it’s time to enter useful values for the rst screen object’s properties. First a quick explanation of each of the
sets of properties.
+ Active: This is the origin and dimensions (in pixels) of the rectangular area on Mbox’s global surface where the
selected screen object (and its applied texture, see below) will be drawn. In most cases, the active width and height
for a screen object will be the same size as its texture dimensions unless some scaling is desired while remapping
the pixels.
+ Texture: This is the origin and dimensions (in pixels) of the rectangular area of the layer’s texture that will be applied
to the selected screen object. These numbers are generally very exact, especially with custom pixel-accurate
content made specically for LED screens.
CAUTION! To ensure that content is centered on image remapping congurations, all texture origin values are evaluated
taking the current conguration’s texture width and height into account. This means that if the conguration’s texture
width and height are set to a size that isn’t the same as the content’s size, the top-left corner of the content won’t appear
at the top-left of the conguration, it will be offset.
Using this tutorial as an example: with a texture that is exactly 900 x 900, this texture’s top-left corner (its 0,0 origin)
would be placed onto the top-left corner of the screen object by using a Texture origin of 0,0 as well. But if a texture
having a size of 720 x 480 is used instead, the screen object’s texture left and top values must be set to 90 and 210
respectively to get the origin of the smaller content into the top-left of the screen object. This is because all textures are
placed so that their center is placed at the center of the conguration’s area. Therefore, smaller content has to be offset
to the left and upwards to get its top-left corner into the top-left corner of the screen object.
The math:
+ Left = (conguration width - content width)/2 -> (900 - 720)/2 = 90
+ Top = (conguration height - content height)/2 -> (900 - 480)/2 = 210
Note: If the content is larger than the conguration’s texture size, then the offset values will be negative.
Step 9. This conguration will require nine square screen objects. The following are the guidelines for their creation:
a. For the active origin of the rst screen object, think about where it should to appear onscreen. Where
it should appear onscreen may be totally arbitrary, or may be driven by the device that the video output
is being sent to - an LED processor perhaps. The processor’s mapping may dictate where the image
should appear onscreen in order to be mapped correctly on the LED wall. For this example make the
active origin (Left, Top) of the rst screen object 100,100. This individual screen object is 300 pixels on
each side and there is no scaling required, so the active width and height of the square will also be 300
and 300.
b. The texture origin of this screen object should be 0,0. This is because the top-left square of the source
texture should be applied to the top-left of the screen object. The texture width and height will be 300 x
300, to match the portion (1/9th) of the larger red square that makes up the entire image.
Note: The ability to copy and paste items when editing image remapping congurations makes it quick to create new
congurations, screen objects, or controls once the measurements and the properties of the rst object have been
entered.