I'm looking into converting a project from using Jitter matrices to shaders and was hoping for some guidance. The patch I'm converting creates a black matrix with alpha 255 as a frame and writes a number of small videos to select locations on it using dstdimstart and dstdimend. This is alphablended over top a large HD video. The small videos also have an oval alpha mask applied so they appear round in the composite video.
How do I apply an oval alpha mask in OpenGL Jitter to the small videos? More generally, what is the best overall approach? Do I create a texture and use the td.resample.jxs shader to add the small videos then use an alphablend shader? I tried using the td.resample.jxs shader directly to the large HD video but the results are small oval videos that constantly disappear.
Thanks for any suggestions!