May be my question isn´t clear. So I´ll try to clarify my intention:

I´d like to wrap my texture. For example having a rectangle I want processing to map a texture two times in vertical and horizontal direction. Using DirectX oder OpenGL I would use texture coordinates in the normalized texture-space which are larger than 1, for my example it would be u = 2 and v = 2. Any other framework would interpret this as a wrapping instruction, mapping the texture multiple times instead of scaling it or doing other stuff. 

I can hardly imagine, that no one ever tried to do this with processing, as it´s one real basic feature when dealing with textures. So, how do you guys handle this?

Here´s a simple workaround, though I´d still like to know, wether or not wrapping is possible (no matter wether I use P3D or OpenGL). 

Currently I do the following:

1. Calculate texture-coordinates with original texture

2. If any texture-coordinate exceeds "1"  I rescale the texture, simply by creating a new image and copy all source-pixels to the new image (for example 2*2 times) => start again with step 1

This works, but it´s dirty as hell. It wastes memory, cpu-time a.s.o. So I´m still searching for the standard way of doing this without wasting 4 or 9 or 16-times more memory than I normally would do when using DirectX or OpenGL.

Yes, I expected something like this. Though I wonder why there aren´t thousands of threads asking this question. Appears to me that this is really a basic feature and I can hardly imagine that everyone uses textures which are the same size of their geometry (or scaled to death and thus looking muddy). During my search I also stumbled across the GLGraphics-Library which is also interesting because of its Shader-support. Though there is a trade-off within my demands, because I´d like to use DXF-Export (which isn´t able to export texture-coordinates anyway), but demands to be called within "regular" processing and the use of GLGraphics which has some really nice features, but probably makes it impossible to export my geometry...I´ll check wether or not I´ll use my simple approach (blowing the texture up to sizes of 2048*2048) and then using texture-coordinates smaller than 1 or I´ll try GLGraphics.

In a nutshell:

Core-Processing isn´t able to use texture-wrapping (hope this is the answer that most people are looking for, when they search for these key-words).