Image Remapping Tutorial; Overview - PRG MBOX User Manual

IMAGE REMAPPING TUTORIAL

Overview

The examples provided in the following pages are intended to mimic two
different type of mapping onto LED panels. The sample content is a square
that can be broken into nine smaller squares. To make the math simpler,
the dimensions of the large square are 900 pixels on each side, and the
smaller squares 300 pixels on each side. The sample image is shown to the
right.
The tutorial will create two separate configurations. The first configuration
will be set up using "Projected Mapping" and the second configuration
will use "Discrete Mapping." Projected mapping is meant to look as if a
projector were pointing at one or more screens that can move through the
projector's beam; as the screens move, the content on them moves too.
Discrete mapping is when the image on each square will stay pinned to the
screen now matter how it moves.
For both of these modes, each of the smaller squares (the screen objects
within each configuration) will need some combination of added control parameters - opacity, texture position, and
position - depending on the intent of the configuration.
External control over the screen object properties of the image remapping is handled through Art-Net or sACN input to
the Mbox server. The control protocol for image remapping must be the same as the control protocol for the entire Mbox
application and is selected on the Patch tab.
While the control for image remapping could be patched to one of the same universes as Mbox, this may be impractical
unless very few channels are required. Ideally, a unique universe should be used. In the case of moving scenery, the
external control data may be derived from positional data that a scenic feedback system creates and which is then
converted into Art-Net or sACN. In other cases (and for this tutorial), extra fixtures/channels can be patched on a
console to generate the necessary data.
For the purposes of this tutorial, each of the nine squares will get three extra channels patched for each of Mbox's
playback layers. These extra channels are to control the square's properties: X Position, Y Position, and Opacity. This
setup uses per-layer controls because the same image remapping configuration can be used on each layer of Mbox and
depending on the design intention, each layer might require separate, unique control of some aspects.
Note: When using image remapping for scenic tracking, per-layer position control may be unnecessary, but per-layer
opacity or intensity may be necessary.
All controls will use 8-bit values for this tutorial to keep things simple and to use fewer channels. With nine squares each
having three channels, and six layers set up on the server, Mbox will need to receive 9 x 3 x 6 = 162 additional channels
from the control source. These could be set up as a custom fixture profile on a lighting console, with one channel for
Opacity, and then a pair of channels for X and Y Position. 54 of these three-channel fixtures could be patched (9 squares
x 6 layers).
The following example illustrations show the editing interface in Mbox. The interface in Mbox Remote is virtually
identical, to that found in the Mbox application. The tutorial assumes that no MultiScreenData.plist file already exists or
that only the default data exists in the file.
Note: To eliminate all Image Remapping data, quit Mbox, then delete the MultiScreenData.plist file and relaunch Mbox.
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