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Blend a slab / videoplane and a qt movie?

March 13, 2013 | 8:12 pm

Hi – I have a slab that is combining the output of syphon with a qt movie. I then want to alpha blend the result of this with another qt movie that will lay over the top and show the slab (syphon + qt) beneath using the alpha channel of the movie. I have the patch that renders the slab, and renders the qt movie, I just can’t seem to find out how to combine the two.


March 13, 2013 | 8:43 pm

you just have to chromakey the results of your first chromakey with another:

– Pasted Max Patch, click to expand. –

March 13, 2013 | 9:01 pm

Is there a way to do this with an alphablend and not a second chromakey? Doing two chromakey operations doesn’t seem to behave the way I want. All I want to do is have my video with alpha play over the top of my blended slab video.


March 13, 2013 | 10:21 pm

Why not use another slab with the co.alphablend.jxs shader?
There’s also a jit.gl.pix solution for alphablend unside the jitter-examples folder


March 13, 2013 | 10:37 pm

Oh, I got it. What you want to do is put your video with the alpha on a videoplane that renders on top of you background video, using the @layer attribute, and setting blend_enable to 1 on your videoplanes. See attached.

M

– Pasted Max Patch, click to expand. –

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