Hey gang! I was curious how one would recreate something like the kirakira sparkle filter in Houdini. It looks like this:
I know how I would do it in OpenGL, basically threshold the video frame then use the brightest pixels to emit a simple billboarded quad... (although I'm not sure why lights don't emit sparkles but that is besides the point). How would one use Houdini to do a similar effect? I have not worked with video data yet... the first thing I thought of was using COPS to get pixel information but it seems like COPS would have to shoot data back up the pipeline to emit some new geometry in the particle system. Maybe there is some sort of way to call POP.emit from COPS vex? I wonder if the workflow would be the same in Nuke, you would still have to go from screenspace pixel data back up to worldspace geometric data to emit the particle.
Also, this is semi-related, but I was trying to get my particles to display a lens flare texture... what is the point of the POP Sprite node? It seems like I am able to assign a texture map just fine by using the Mantra Classic Shader material with "emissive" enabled to read from a map. What is the usual way that POP particles render as camera-facing billboarded quads?