[vlc-devel] [PATCH 1/2] interop_dxva2: load extension from vlc_gl_t

[Steve Lhomme]

On 2021-02-15 19:05, Alexandre Janniaux wrote:
> The only users of those extensions are interop modules, so only
> interop_dxva2 for extension related to WGL integration.
> 
> By moving the loading of those extension to the interop, we can have
> them working even when the OpenGL platform context is provided by the
> vglmem (vgl.c) module callbacks, allowing hardware acceleration even
> when using the libvlc OpenGL callbacks.
> 
> Filters would likely be using only OpenGL extensions that are already
> available, but could be using the same mechanism in the worst-case
> scenario.
> 
> Fixes #25234
> ---
>   modules/video_output/Makefile.am            |  2 +-
>   modules/video_output/opengl/interop_dxva2.c | 30 ++++++++++++++++++---
>   2 files changed, 28 insertions(+), 4 deletions(-)
> 
> diff --git a/modules/video_output/Makefile.am b/modules/video_output/Makefile.am
> index 375da4b28d..86ed27d85d 100644
> --- a/modules/video_output/Makefile.am
> +++ b/modules/video_output/Makefile.am
> @@ -121,7 +121,7 @@ libdirect3d9_plugin_la_LDFLAGS = $(AM_LDFLAGS) -rpath '$(voutdir)'
>   libglinterop_dxva2_plugin_la_SOURCES = video_output/opengl/interop_dxva2.c \
>   	video_output/opengl/interop.h
>   libglinterop_dxva2_plugin_la_CFLAGS = $(AM_CFLAGS) $(GL_CFLAGS)
> -libglinterop_dxva2_plugin_la_LIBADD = libd3d9_common.la
> +libglinterop_dxva2_plugin_la_LIBADD = libd3d9_common.la -lopengl32
>   
>   if HAVE_WIN32_DESKTOP
>   vout_LTLIBRARIES += $(LTLIBdirect3d9)
> diff --git a/modules/video_output/opengl/interop_dxva2.c b/modules/video_output/opengl/interop_dxva2.c
> index 2b32e93272..225db1d430 100644
> --- a/modules/video_output/opengl/interop_dxva2.c
> +++ b/modules/video_output/opengl/interop_dxva2.c
> @@ -71,6 +71,8 @@ vlc_module_begin ()
>   vlc_module_end ()
>   
>   struct wgl_vt {
> +    PFNWGLGETEXTENSIONSSTRINGEXTPROC     GetExtensionsStringEXT;
> +    PFNWGLGETEXTENSIONSSTRINGARBPROC     GetExtensionsStringARB;
>       PFNWGLDXSETRESOURCESHAREHANDLENVPROC DXSetResourceShareHandleNV;
>       PFNWGLDXOPENDEVICENVPROC             DXOpenDeviceNV;
>       PFNWGLDXCLOSEDEVICENVPROC            DXCloseDeviceNV;
> @@ -422,15 +424,37 @@ GLConvOpen(vlc_object_t *obj)
>           return VLC_EGENERIC;
>       }
>   
> -    if (interop->gl->ext != VLC_GL_EXT_WGL || !interop->gl->wgl.getExtensionsString)
> +    if (interop->gl->surface == NULL)
>           return VLC_EGENERIC;
>   
> -    const char *wglExt = interop->gl->wgl.getExtensionsString(interop->gl);
> +    HDC hGLDC = NULL;
> +    switch (interop->gl->surface->type)
> +    {
> +        case VOUT_WINDOW_TYPE_HWND:
> +        case VOUT_WINDOW_TYPE_DUMMY:

The wgl version only allowed VOUT_WINDOW_TYPE_HWND. I suppose it is safe 
because there is a check on interop->gl->surface ? If so why limit to 
the type of window at all ?

Also if wglGetExtensionsStringEXT is available this is created but will 
never be used at all. May it's easier to handle the 
wglGetExtensionsStringEXT case first and if it's not there try the HDC way ?

> +            hGLDC = wglGetCurrentDC();
> +            break;
> +        default: return VLC_EGENERIC;
> +    }
> +
> +    if (hGLDC == NULL)
> +        return VLC_EGENERIC;
> +
> +    struct wgl_vt vt;
> +    vt.GetExtensionsStringEXT =
> +        vlc_gl_GetProcAddress(interop->gl, "wglGetExtensionsStringEXT");
> +    vt.GetExtensionsStringARB =
> +        vlc_gl_GetProcAddress(interop->gl, "wglGetExtensionsStringARB");

This seems like what the LOAD_EXT macro defined below is doing. Maybe 
move the macro up and use it, for consistency. You already move the 
struct it's writing to anyway.

> +
> +    const char *wglExt = NULL;
> +    if (vt.GetExtensionsStringEXT)
> +        wglExt = vt.GetExtensionsStringEXT();
> +    else if (vt.GetExtensionsStringARB)
> +        wglExt = vt.GetExtensionsStringARB(hGLDC);
>   
>       if (wglExt == NULL || !vlc_gl_StrHasToken(wglExt, "WGL_NV_DX_interop"))
>           return VLC_EGENERIC;
>   
> -    struct wgl_vt vt;
>   #define LOAD_EXT(name, type) do { \
>       vt.name = (type) vlc_gl_GetProcAddress(interop->gl, "wgl" #name); \
>       if (!vt.name) { \
> -- 
> 2.30.1
> 
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