FSAA only works on default render target?

ackle · August 1, 2025, 7:39am

I’ve noticed that FSAA (enabled by using the Project → Display → Samples setting) only seems to work when drawing to the default render target. When I draw to an intermediate RT first and then copy that to the default RT, no anti-aliasing is done, even if I set the filtering mode to linear for the copying.

Has anyone else encountered this, and if so, is there a workaround? Or should I file a bug report? (I do have my own FXAA shader that I could use, but I’d prefer to just use the built-in FSAA if possible.)

(I’m on 1.10.3, btw.)

ackle · August 1, 2025, 7:59am

Hmm, I thought about it a bit more, and I suppose that if you were to have anti-aliasing when drawing to an intermediate RT, then you’d need to selectively enable/disable it for specific attachments because you might be storing things like normals and depth, and you wouldn’t want to anti-alias those.

jhonny.goransson · August 1, 2025, 8:10am

Yeah we need to add a setting for that when creating the RT, please open a feature request.

ackle · August 1, 2025, 9:01am

Here you go:

github.com/defold/defold

Enable FSAA for individual attachments in custom render targets

opened 09:00AM - 01 Aug 25 UTC

akhleung

feature request

**Is your feature request related to a problem? Please describe (REQUIRED):** F…SAA (enabled via **Project -> Display -> Samples**) only works when drawing to the default render target (i.e., directly to the screen). However, it's common to draw to intermediate RTs first in order to do post-processing, but FSAA will not be applied in this case. It would be very useful to allow FSAA for any render target so that games that do post-processing can look more polished as well. **Describe the solution you'd like (REQUIRED):** Instead of a global setting that only applies to the default render target, allow FSAA to be **enabled / disabled for individual attachments** in any render target. This level of granularity is necessary because, for example, attachments that contain colors should be anti-aliased, but attachments that contain other data such as normals, depth, material properties, etc, should not be anti-aliased. **Describe alternatives you've considered (REQUIRED):** A project can use custom anti-aliasing shaders, but these will incur a performance cost, and it's suboptimal to do this when a solution is already part of the engine. **Additional context (OPTIONAL):** Brief discussion here: https://forum.defold.com/t/fsaa-only-works-on-default-render-target/81107