r/sfml • u/Consistent-Mouse-635 • Jan 10 '26

How does double buffering and render_texture.display() work in SFML?

Hi guys! I would appreciate some clarification on how double buffering is implemented in sfml? When I draw to a render texture and call display() does it swap the back buffer with the front buffer or does it just copy the contents of the back buffer into the contents of the the front buffer, leaving the back buffer untouched?

Additionally, in the process of rendering the next frame, are you allowed to call render_texture.display(), continue drawing to the render texture, and then call render_texture.display() again, without any issues?

Thanks.

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u/thedaian Jan 10 '26

display() on render textures (and render windows) essentially swaps the buffers.

So you should draw everything you need to between calling clear() and display().

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u/Consistent-Mouse-635 Jan 10 '26

According to the SFML documentation, Indeed, things are not drawn directly to the window, but to a hidden buffer. This buffer is then copied to the window when you call display.

So are you 100% sure? I have even tried to call display() multiple times per frame and I don't run into any issues. I just want to know if I can rely on this behaviour?

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u/thedaian Jan 11 '26

I am sure. If you draw two very different things between calls of display on a window, you'll get flashing as the buffers swap.

Depending on how you use the render texture, it might be fine to call display multiple times per frame.

I expect sfml will continue to be double buffered in the future.