[vlc-devel] [PATCH 5/5] doc: QtGl: add details on GetProcAddress impl

[Alexandre Janniaux]

Hi,

I just realised the document I sent was incomplete, it was
missing this part:

diff --git a/doc/libvlc/QtGL/qtvlcwidget.cpp b/doc/libvlc/QtGL/qtvlcwidget.cpp
index f5d9adcd3c..134ad06601 100644
--- a/doc/libvlc/QtGL/qtvlcwidget.cpp
+++ b/doc/libvlc/QtGL/qtvlcwidget.cpp
@@ -157,7 +157,10 @@ public:
          * mentioned in the API. Cf QPlatformOpenGLContext::getProcAddress.
          * Thus, we don't need to wrap the function symbols here, but it might
          * fail to work (not crash though) on exotic platforms since Qt doesn't
-         * commit to this behaviour.  */
+         * commit to this behaviour. A way to handle this in a more stable way
+         * would be to store the mContext->functions() table in a thread local
+         * variable, and wrap every call to OpenGL in a function using this
+         * thread local state to call the correct variant. */
         return reinterpret_cast<void*>(that->mContext->getProcAddress(current));
     }

Regards,
--
Alexandre Janniaux
Videolabs

On Mon, Nov 09, 2020 at 06:15:03PM +0100, Alexandre Janniaux wrote:
> ---
>  doc/libvlc/QtGL/qtvlcwidget.cpp | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/doc/libvlc/QtGL/qtvlcwidget.cpp b/doc/libvlc/QtGL/qtvlcwidget.cpp
> index e33f6a6c08..f5d9adcd3c 100644
> --- a/doc/libvlc/QtGL/qtvlcwidget.cpp
> +++ b/doc/libvlc/QtGL/qtvlcwidget.cpp
> @@ -153,6 +153,11 @@ public:
>      static void* get_proc_address(void* data, const char* current)
>      {
>          VLCVideo* that = static_cast<VLCVideo*>(data);
> +        /* Qt usual expects core symbols to be queryable, even though it's not
> +         * mentioned in the API. Cf QPlatformOpenGLContext::getProcAddress.
> +         * Thus, we don't need to wrap the function symbols here, but it might
> +         * fail to work (not crash though) on exotic platforms since Qt doesn't
> +         * commit to this behaviour.  */
>          return reinterpret_cast<void*>(that->mContext->getProcAddress(current));
>      }
>
> --
> 2.29.2
>