I am making a patch which composes two different matrixes on top of each other, keeping the alpha intact. I am currently doing this with 2 jit.gl.videoplanes because I need to be able to rotate, scale and move them dynamically. I need to render this to a matrix so I can then export the resulting matrix. There is already a fullscreen window showing other things and I don't want to create an extra window just for this.
But the problem is that the result looks different in a matrix (or jit.pwindow) or a window. The window renders the desired effect (the right layer order and alpha) but rendering to a matrix creates a different composition somehow. What is the difference to rendering to matrix or window? I am using Max 5.1.3 and OS X.
I created a sample patch which does the same thing twice, only once rendering to a window and once to a pwindow. Load to images and use the bang button. It is best to load a PNG with alpha transparency on the first read.