How is "Trails" implemented

[sefreso]

Hello,

I would like to port Resolume's "Trails" video effect into a GLSL plugin.

I have been looking online for tutorials but can't find the right search keywords.

I don't really know where to start.

Would anyone outline the main steps in producing the Trails video effect?

Thanks!

[edwin]

You need to retain a copy of the last rendered frame.
So keep a copy and perform a blend with the new Frame.

[Piotrus04]

@Edwin, do you have a source to provide because it is not only get a copy of rendered, we also have to manage the double call to the same instance, when the clip play and preview mode are both activated.
In this case, the plugin must manage two different dimensions, the one from the layer or clip sent to preview, and the one sent to the output.
Double means two fbos of different dimensions?
How to manage this?
Best