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media/gstreamer: Support using GL for video for Windows

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Add support to share the WGL context in GDK with the WGL context in GStreamer,
so that we can also use OpenGL in the gstreamer media backend to playback
videos.  For now OpenGL/ES is not supported for this under Windows.

The process of setting this up in Windows is a little bit more involved, as:

*  The OpenGL support in GstGL requires a GL 4.1 Core context, but we may just
   get the GL version from wglCreateContextAttribsARB() that we pass into the
   attributes, which is 3.2 by default.  So, try to ask for a 4.1 Core context
   first if we are asking for anything less.

*  There is only one GstDisplay available for Windows, so we just use
   gst_gl_display_new().

*  We must explicitly tell libepoxy that we are using wglMakeCurrent() outside
   of libepoxy that is being used in GdkGL, otherwise we would end up crashing
   as the GL/WGL function pointers would become invalid.

*  We must also deactivate temporarily the underlying WGL context that was made
   current by gdk_gl_context_make_current() so that when
   gst_gl_display_create_context() calls wglShareLists(), we won't get bitten
   by error 0xaa (resource busy), as some drivers don't handle this well when
   the GL context is current in another thread.

For the last two points we make use of macros defined by the platforms that the
build is done for to help us carry out the necessary tasks as needed.

Thanks to Matthew Waters for the info on integrating GstGL and windowing
toolkits on Windows.
This commit is contained in:
Chun-wei Fan 2021-02-13 18:40:56 +08:00
parent 21057fb857
commit 52d1c0c271
3 changed files with 96 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

36
gdk/win32/gdkglcontext-win32.c
View File

@ -674,7 +674,7 @@ _create_gl_context (HDC hdc,
}
else
{
HGLRC hglrc;
HGLRC hglrc = NULL;
if (!wglMakeCurrent (hdc, hglrc_base))
{
@ -682,13 +682,33 @@ _create_gl_context (HDC hdc,
goto gl_fail;
}
hglrc = _create_gl_context_with_attribs (hdc,
hglrc_base,
share,
flags,
major,
minor,
is_legacy);
/*
* We need a Core GL 4.1 context in order to use the GL support in
* the GStreamer media widget backend, but wglCreateContextAttribsARB()
* may only give us the GL context version that we ask for here, and
* nothing more. So, if we are asking for a pre-GL 4.1 context,
* try to ask for a 4.1 context explicitly first. If that is not supported,
* then we fall back to whatever version that we were asking for (or, even a
* legacy context if that fails), at a price of not able to have GL support
* for the media GStreamer backend.
*/
if (major < 4 || (major == 4 && minor < 1))
hglrc = _create_gl_context_with_attribs (hdc,
hglrc_base,
share,
flags,
4,
1,
is_legacy);
if (hglrc == NULL)
hglrc = _create_gl_context_with_attribs (hdc,
hglrc_base,
share,
flags,
major,
minor,
is_legacy);
/* return the legacy context we have if it could be setup properly, in case the 3.0+ context creation failed */
if (hglrc == NULL)

13
modules/media/gtkgstpaintable.c
View File

@ -118,18 +118,6 @@ gtk_gst_paintable_video_renderer_create_video_sink (GstPlayerVideoRenderer *rend
GtkGstPaintable *self = GTK_GST_PAINTABLE (renderer);
GstElement *sink, *glsinkbin;
#if GST_GL_HAVE_WINDOW_WIN32 && GST_GL_HAVE_PLATFORM_WGL && defined (GDK_WINDOWING_WIN32)
/*
* Unfortunately, we can't connect the GstGLContext with our GDKGLContext,
* since gdk_gl_context_make_current(), which calls wglMakeCurrent(), does not
* allow us to share WGL contexts across threads, which will cause a crash.
* See MR !3034, so no WGL in the gstreamer media backend :(
*/
sink = g_object_new (GTK_TYPE_GST_SINK,
"paintable", self,
NULL);
return sink;
#else
sink = g_object_new (GTK_TYPE_GST_SINK,
"paintable", self,
"gl-context", self->context,
@ -143,7 +131,6 @@ gtk_gst_paintable_video_renderer_create_video_sink (GstPlayerVideoRenderer *rend
g_object_set (glsinkbin, "sink", sink, NULL);
return glsinkbin;
#endif
}
static void

76
modules/media/gtkgstsink.c
View File

@ -42,6 +42,11 @@
#include <gst/gl/wayland/gstgldisplay_wayland.h>
#endif
#if GST_GL_HAVE_WINDOW_WIN32 && GST_GL_HAVE_PLATFORM_WGL && defined (GDK_WINDOWING_WIN32)
#include <gdk/win32/gdkwin32.h>
#include <epoxy/wgl.h>
#endif
#include <gst/gl/gstglfuncs.h>
enum {
@ -348,22 +353,50 @@ gtk_gst_sink_show_frame (GstVideoSink *vsink,
return GST_FLOW_OK;
}
#if GST_GL_HAVE_WINDOW_WIN32 && GST_GL_HAVE_PLATFORM_WGL && defined (GDK_WINDOWING_WIN32)
#define HANDLE_EXTERNAL_WGL_MAKE_CURRENT epoxy_handle_external_wglMakeCurrent()
#define DEACTIVATE_WGL_CONTEXT(ctx) deactivate_gdk_wgl_context(ctx)
#define REACTIVATE_WGL_CONTEXT(ctx) reactivate_gdk_wgl_context(ctx)
static void
deactivate_gdk_wgl_context (GdkGLContext *ctx)
{
if (!gdk_gl_context_get_use_es (ctx))
{
HDC hdc = GetDC (GDK_SURFACE_HWND (gdk_gl_context_get_surface (ctx)));
wglMakeCurrent (hdc, NULL);
}
}
static void
reactivate_gdk_wgl_context (GdkGLContext *ctx)
{
if (!gdk_gl_context_get_use_es (ctx))
gdk_gl_context_make_current (ctx);
}
#else
#define HANDLE_EXTERNAL_WGL_MAKE_CURRENT
#define DEACTIVATE_WGL_CONTEXT(ctx)
#define REACTIVATE_WGL_CONTEXT(ctx)
#endif
static void
gtk_gst_sink_initialize_gl (GtkGstSink *self)
{
GdkDisplay *display;
GError *error = NULL;
GstGLPlatform platform = GST_GL_PLATFORM_NONE;
GstGLAPI gl_api = GST_GL_API_NONE;
guintptr gl_handle = 0;
display = gdk_gl_context_get_display (self->gdk_context);
HANDLE_EXTERNAL_WGL_MAKE_CURRENT;
gdk_gl_context_make_current (self->gdk_context);
#ifdef HAVE_GST_X11_SUPPORT
if (GDK_IS_X11_DISPLAY (display))
{
GstGLPlatform platform;
GstGLAPI gl_api;
guintptr gl_handle;
gpointer display_ptr;
#if GST_GL_HAVE_PLATFORM_EGL
@ -387,6 +420,7 @@ gtk_gst_sink_initialize_gl (GtkGstSink *self)
gl_api = gst_gl_context_get_current_gl_api (platform, NULL, NULL);
gl_handle = gst_gl_context_get_current_gl_context (platform);
if (gl_handle)
{
self->gst_app_context = gst_gl_context_new_wrapped (self->gst_display, gl_handle, platform, gl_api);
@ -402,13 +436,10 @@ gtk_gst_sink_initialize_gl (GtkGstSink *self)
#ifdef HAVE_GST_WAYLAND_SUPPORT
if (GDK_IS_WAYLAND_DISPLAY (display))
{
GstGLPlatform platform = GST_GL_PLATFORM_GLX;
GstGLAPI gl_api;
guintptr gl_handle;
platform = GST_GL_PLATFORM_EGL;
GST_DEBUG_OBJECT (self, "got EGL on Wayland!");
platform = GST_GL_PLATFORM_EGL;
gl_api = gst_gl_context_get_current_gl_api (platform, NULL, NULL);
gl_handle = gst_gl_context_get_current_gl_context (platform);
@ -427,6 +458,30 @@ gtk_gst_sink_initialize_gl (GtkGstSink *self)
}
}
else
#endif
#if GST_GL_HAVE_WINDOW_WIN32 && GST_GL_HAVE_PLATFORM_WGL && defined (GDK_WINDOWING_WIN32)
if (GDK_IS_WIN32_DISPLAY (display) &&
!gdk_gl_context_get_use_es (self->gdk_context))
{
platform = GST_GL_PLATFORM_WGL;
GST_DEBUG_OBJECT (self, "got WGL on Win32!");
gl_api = gst_gl_context_get_current_gl_api (platform, NULL, NULL);
gl_handle = gst_gl_context_get_current_gl_context (platform);
if (gl_handle)
{
self->gst_display = gst_gl_display_new ();
self->gst_app_context = gst_gl_context_new_wrapped (self->gst_display, gl_handle, platform, gl_api);
}
else
{
GST_ERROR_OBJECT (self, "Failed to get handle from GdkGLContext, not using WGL");
return;
}
}
else
#endif
{
GST_INFO_OBJECT (self, "Unsupported GDK display %s for GL", G_OBJECT_TYPE_NAME (display));
@ -436,16 +491,19 @@ gtk_gst_sink_initialize_gl (GtkGstSink *self)
g_assert (self->gst_app_context != NULL);
gst_gl_context_activate (self->gst_app_context, TRUE);
if (!gst_gl_context_fill_info (self->gst_app_context, &error))
{
GST_ERROR_OBJECT (self, "failed to retrieve GDK context info: %s", error->message);
g_clear_error (&error);
g_clear_object (&self->gst_app_context);
g_clear_object (&self->gst_display);
HANDLE_EXTERNAL_WGL_MAKE_CURRENT;
return;
}
else
{
DEACTIVATE_WGL_CONTEXT (self->gdk_context);
gst_gl_context_activate (self->gst_app_context, FALSE);
}
@ -455,8 +513,10 @@ gtk_gst_sink_initialize_gl (GtkGstSink *self)
g_error_free (error);
g_clear_object (&self->gst_app_context);
g_clear_object (&self->gst_display);
return;
}
HANDLE_EXTERNAL_WGL_MAKE_CURRENT;
REACTIVATE_WGL_CONTEXT (self->gdk_context);
}
static void