Re: [PATCH] ui/egl-helpers: Fix FBO recreation and prevent texture accidental deletion

["Marc-André Lureau" <marcandre.lureau@gmail.com>]

Hi

On Tue, Mar 3, 2026 at 5:14 AM <dongwon.kim@intel.com> wrote:
>
> From: Dongwon Kim <dongwon.kim@intel.com>
>
> When egl_fb_setup_for_tex is called, we must handle cases
> where the texture ID is reused across different GL contexts.
>
> Texture Preservation - If the new texture ID matches
> the cached ID, we must skip egl_fb_delete_texture to avoid
> destroying the texture we are about to use.
>
> FBO Recreation - Because FBOs are context-local and not shared,
> a cached FBO ID from a previous context is invalid. We must
> generate a new FBO handle if we are re-validating the same
> texture ID in a potentially new context.
>
> This prevents stale FBO usage and unintended texture deletion
> during context transitions.
>
> Cc: Gerd Hoffmann <kraxel@redhat.com>
> Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
> Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
> Signed-off-by: Dongwon Kim <dongwon.kim@intel.com>
> ---
>  ui/egl-helpers.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/ui/egl-helpers.c b/ui/egl-helpers.c
> index e3f2872cc1..7ac64f3ba8 100644
> --- a/ui/egl-helpers.c
> +++ b/ui/egl-helpers.c
> @@ -111,15 +111,23 @@ void egl_fb_setup_default(egl_fb *fb, int width, int height, int x, int y)
>  void egl_fb_setup_for_tex(egl_fb *fb, int width, int height,
>                            GLuint texture, bool delete)
>  {
> -    egl_fb_delete_texture(fb);
> +    if (fb->texture != texture) {
> +        egl_fb_delete_texture(fb);
> +    }

That change makes sense, and prevents reusing a destroyed texture.

> +
> +    /*
> +     * If fb->texture == texture, the existing fb->framebuffer is tied to
> +     * a previous GL context. Since FBOs are not shared across contexts,
> +     * we must create a new FBO for the current context.
> +     */
> +    if (!fb->framebuffer || (fb->texture == texture)) {
> +        glGenFramebuffers(1, &fb->framebuffer);
> +    }

This, I don't understand. Assuming the framebuffer is used in a
different context, shouldn't it generate a new framebuffer regardless
of the texture?

Also, aren't these leaking framebuffers?

Can you identify cases where egl_fb_setup_for_tex() is reused in a
different context? shouldn't we prevent this instead?

thanks

>
>      fb->width = width;
>      fb->height = height;
>      fb->texture = texture;
>      fb->delete_texture = delete;
> -    if (!fb->framebuffer) {
> -        glGenFramebuffers(1, &fb->framebuffer);
> -    }
>
>      glBindFramebuffer(GL_FRAMEBUFFER_EXT, fb->framebuffer);
>      glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
> --
> 2.43.0
>
>


-- 
Marc-André Lureau