jit.gl.meshwarp doesn't show video?
Maybe there's something obvious I'm missing here, but I couldn't find anything about this on the forums yet: jit.gl.meshwarp works well with basically any video source (usually even with direct matrix input) but won't display a specific source video I'm sending (which is a standard 4 plane jit.matrix - generated by some basic color controls).
1) The source video displays fine when I connect it directly to a jit.pworld, also after I put it through a jit.gl.texture - so it's probably not a texture conversion issue
2) The jit.gl.meshwarp connected to the source video is making a layer as expected, but it's transparent / showing nothing
3) Basically anything else works - I included a fairly random jit.expr here which displays fine when connected to the same jit.gl.meshwarp
(Sorry for the badly organized patch, this is pulled out of a bigger patch)
The matrix named red has its entire alpha channel filled with zeroes, which means full transparency. In the subpatcher feeding the matrix, replace your "clear" message by "clear, fillplane 0 255" and then you'll be able to see the matrix with jit.gl.meshwarp.
Thanks again for your help - that solved it. But now I'm starting to wonder why a totally transparent video shows up at all in the jit.pworld or jit.pwindow but not in the jitter world itself.
Because of the way they handle blending. When you send a texture/matrix straight into jit.pworld, I guess it is equivalent as sending it into a jit.gl.videoplane rendered into this world. By default jit.gl.videoplane has @blend_enable 0, which will make you see the colors regardless of the alpha channel.
jit.pwindow will simply not blend at all, so the alpha channel won't have any impact on what you see on it.
And I guess jit.gl.meshwarp necessarily work with blend enabled, so transparency will be rendered no matter what.
See here how you can make your matrix to disappear/appear when you enable/disable blend_enable of the videoplane.