sdlshare2: Fix race conditions

The client-draw callback is running on the GL Thread, which will
be required to map the buffer. Map early, and pass the mapped
frame instead. On top of that, make sure to signal any pending
draw before trying to push EOS, as some pad locks might be taken.
This is the cost of using the same thread to control GStreamer and
to render GL.
This commit is contained in:
Nicolas Dufresne 2017-11-24 16:58:21 -05:00
parent c9e755d79e
commit 4f36f75eb1

View file

@ -66,13 +66,9 @@ InitGL (int Width, int Height) // We call this right after our OpenGL window is
/* The main drawing function. */ /* The main drawing function. */
static void static void
DrawGLScene (GstSample * sample) DrawGLScene (GstVideoFrame * v_frame)
{ {
GstVideoFrame v_frame;
GstVideoInfo v_info;
guint texture = 0; guint texture = 0;
GstBuffer *buf = gst_sample_get_buffer (sample);
GstCaps *caps = gst_sample_get_caps (sample);
#ifdef WIN32 #ifdef WIN32
if (!wglGetCurrentContext ()) if (!wglGetCurrentContext ())
@ -82,14 +78,7 @@ DrawGLScene (GstSample * sample)
return; return;
#endif #endif
gst_video_info_from_caps (&v_info, caps); texture = *(guint *) v_frame->data[0];
if (!gst_video_frame_map (&v_frame, &v_info, buf, GST_MAP_READ | GST_MAP_GL)) {
g_warning ("Failed to map the video buffer");
return;
}
texture = *(guint *) v_frame.data[0];
glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear The Screen And The Depth Buffer glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear The Screen And The Depth Buffer
glLoadIdentity (); // Reset The View glLoadIdentity (); // Reset The View
@ -139,8 +128,21 @@ DrawGLScene (GstSample * sample)
// swap buffers to display, since we're double buffered. // swap buffers to display, since we're double buffered.
SDL_GL_SwapBuffers (); SDL_GL_SwapBuffers ();
}
gst_video_frame_unmap (&v_frame); static GMutex app_lock;
static GCond app_cond;
static gboolean app_rendered = FALSE;
static gboolean app_quit = FALSE;
static void
stop_pipeline (GstElement * pipeline)
{
g_mutex_lock (&app_lock);
app_quit = TRUE;
g_cond_signal (&app_cond);
g_mutex_unlock (&app_lock);
gst_element_send_event (pipeline, gst_event_new_eos ());
} }
static gboolean static gboolean
@ -151,12 +153,12 @@ update_sdl_scene (gpointer data)
while (SDL_PollEvent (&event)) { while (SDL_PollEvent (&event)) {
if (event.type == SDL_QUIT) { if (event.type == SDL_QUIT) {
gst_element_send_event (GST_ELEMENT (pipeline), gst_event_new_eos ()); stop_pipeline (pipeline);
return FALSE; return FALSE;
} }
if (event.type == SDL_KEYDOWN) { if (event.type == SDL_KEYDOWN) {
if (event.key.keysym.sym == SDLK_ESCAPE) { if (event.key.keysym.sym == SDLK_ESCAPE) {
gst_element_send_event (GST_ELEMENT (pipeline), gst_event_new_eos ()); stop_pipeline (pipeline);
return FALSE; return FALSE;
} }
} }
@ -165,18 +167,15 @@ update_sdl_scene (gpointer data)
return TRUE; return TRUE;
} }
static GMutex app_lock;
static GCond app_cond;
static gboolean static gboolean
executeCallback (gpointer data) executeCallback (gpointer data)
{ {
GstSample *sample = (GstSample *) data;
g_mutex_lock (&app_lock); g_mutex_lock (&app_lock);
DrawGLScene (sample); if (!app_quit)
DrawGLScene (data);
app_rendered = TRUE;
g_cond_signal (&app_cond); g_cond_signal (&app_cond);
g_mutex_unlock (&app_lock); g_mutex_unlock (&app_lock);
@ -187,12 +186,31 @@ static gboolean
on_client_draw (GstElement * glsink, GstGLContext * context, GstSample * sample, on_client_draw (GstElement * glsink, GstGLContext * context, GstSample * sample,
gpointer data) gpointer data)
{ {
GstBuffer *buf = gst_sample_get_buffer (sample);
GstCaps *caps = gst_sample_get_caps (sample);
GstVideoFrame v_frame;
GstVideoInfo v_info;
/* FIXME don't do that every frame */
gst_video_info_from_caps (&v_info, caps);
if (!gst_video_frame_map (&v_frame, &v_info, buf, GST_MAP_READ | GST_MAP_GL)) {
g_warning ("Failed to map the video buffer");
return TRUE;
}
g_mutex_lock (&app_lock); g_mutex_lock (&app_lock);
g_idle_add_full (G_PRIORITY_HIGH, executeCallback, sample, NULL); app_rendered = FALSE;
g_cond_wait (&app_cond, &app_lock); g_idle_add_full (G_PRIORITY_HIGH, executeCallback, &v_frame, NULL);
while (!app_rendered && !app_quit)
g_cond_wait (&app_cond, &app_lock);
g_mutex_unlock (&app_lock); g_mutex_unlock (&app_lock);
gst_video_frame_unmap (&v_frame);
return TRUE; return TRUE;
} }