during Malte Steiners artist-in-residency at the Open City in Chile in June 2011 he researched the possibilities of creating videomapping with Pure Data.
an early example while creating the patch in Chile
Videomapping applies distortion to an image so when it is projected on a non flat surface it looks right. In the installation Impossible City, Steiner created with videomapping several screen with only one projector.
For the installation Steiner created an abstraction which provides the GEM object for mapping, editing of the four corner points with number objects and persistent storage of the settings. First the object was a polygon but it gives problems as shown below. Even a rectangle polygon is made of 2 triangles so under certain circumstances you can see the seam of the two, resulting in ugly distortions.
the curve3d Gem object is suited much better because it creates a soft bezier curve.
Bugs so far:
- you can use several b4planes in a patch but pressing the write button to store a setting result in a crash. For creating mapping it must be done in a patch with a single b4plane object
- its mirrord, didn't noticed it first because of the work with a webcam picture which mirrord feels natural. Easy to correct by changing the left and right points