How to make effect plugin render result exceed layer size range? Like motion tile effect.

[Javier Yang]

Hi guys,

I want to write an effect plugin which can achieve that render result can exceed layer original size, in AfterEffects plugin, there is an effect called Motion Tile, the result from this effect can exceed layer size like image below, thanks!

[James Whiffin]

You can expand the boundaries in frame setup if you're not using smartFX, or by increasing the output rectangle in PreRender when using smartFX.

[Javier Yang]

Many thanks man, I have a try 😄

[James Whiffin · Accepted solution]

No worries 🙂 if you go the first route you'll need to set PF_OutFlag_I_EXPAND_BUFFER. If you go with smartFX you'll need to set 

extra->output->flags |= PF_RenderOutputFlag_RETURNS_EXTRA_PIXELS;

[Javier Yang]

Gocha, I use SmartRender() and OpenGL API, if I want to change size of result dynamically base on user modyfing parameter, how to achieve?

[James Whiffin]

In pre_render, checkout the user param (slider) and increase the output rectangle based on the slider.

[Javier Yang]

Thanks~

[Javier Yang]

Still not make it work, I add following code in PreRender:

[James Whiffin · Accepted solution]

Try setting both output result rects to the expanded_rect. Also if you want you can expand the request rect to recapture any offscreen pixels, not sure if that is relevant to the plugin you are making. 

[Javier Yang]

I am a little bit comfused, what the different between req.rect and in_result.rect?

[James Whiffin]

The req.rect is where you ask ae for a region of pixels when you call checkout_layer. The result.rect is populated from your PF_RenderRequest and the PF_CheckoutResult result_rect is the rect of pixels you can actually get, since parts of your request rect may not actually contain pixels, depending on masks, upstream effect buffer behaviours, etc. 

[Javier Yang]

Thanks a lot! Btw, if I want to get the merge result from all the layers below the layer which I apply my effect plugin, how to get the result of that merge image?

[James Whiffin]

If the layer is an adjustment layer you will get that result. If your layer is a solid or footage, it's not possible (to my knowledge)

[Javier Yang]

OK~