mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer-rs.git
synced 2024-11-24 10:31:03 +00:00
examples/glupload: Provide new shared GLContext via pad probe
On certain GL drivers on Windows (e.g. those for Intel Arc) we see that
creation of a shared context based on our wrapped WGL context (from
`glutin`) fails with `ERROR_BUSY`:
0:00:00.509113900 29460 000001E07A782CC0 DEBUG glcontext gstglcontext.c:1227:gst_gl_context_create_thread:<glcontextwgl0> Creating thread
0:00:00.509352100 29460 000001E07A782CC0 FIXME glcontext gstglcontext.c:2041:gst_gl_wrapped_context_get_config:<glwrappedcontext0> wrapped context could not retrieve config. The application may be missing a call to gst_gl_context_fill_info() or the specific platform implemention is not implemented for retrieving the config from a wrapped OpenGL context.
0:00:00.543157300 29460 000001E07A782CC0 INFO glcontext gstglcontext_wgl.c:402:gst_gl_context_wgl_choose_format:<glcontextwgl0> chosen config gst-gl-context-config, platform=(GstGLPlatform)GST_GL_PLATFORM_WGL, red-size=(int)8, blue-size=(int)8, green-size=(int)8, alpha-size=(int)8, depth-size=(int)24, stencil-size=(int)8, native-visual-id=(uint)5, surface-type=(GstGLConfigSurfaceType)GST_GL_CONFIG_SURFACE_TYPE_WINDOW;
0:00:00.543770000 29460 000001E07A782CC0 INFO glcontext gstglcontext.c:1322:gst_gl_context_create_thread:<glcontextwgl0> Attempting to create opengl context. user chosen api(s) (any), compiled api support (opengl opengl3) display api (any)
0:00:00.553201100 29460 000001E07A782CC0 DEBUG glcontext gstglcontext_wgl.c:186:gst_gl_context_wgl_create_context: gl context created: 65537
0:00:00.613589500 29460 000001E07A782CC0 DEBUG glcontext gstglcontext_wgl.c:214:gst_gl_context_wgl_create_context:<glcontextwgl0> Available WGL extensions WGL_EXT_depth_float WGL_ARB_buffer_region WGL_ARB_extensions_string WGL_ARB_make_current_read WGL_ARB_pixel_format WGL_ARB_pbuffer WGL_EXT_extensions_string WGL_EXT_swap_control WGL_ARB_multisample WGL_ARB_pixel_format_float WGL_ARB_framebuffer_sRGB WGL_ARB_create_context WGL_ARB_create_context_profile WGL_EXT_pixel_format_packed_float WGL_EXT_create_context_es_profile WGL_EXT_create_context_es2_profile WGL_NV_DX_interop WGL_NV_DX_interop2 WGL_ARB_robustness_application_isolation WGL_ARB_robustness_share_group_isolation WGL_ARB_create_context_robustness WGL_ARB_context_flush_control
0:00:00.614036500 29460 000001E07A782CC0 DEBUG glcontext gstglcontext_wgl.c:235:gst_gl_context_wgl_create_context:<glcontextwgl0> trying to create a GL 4.5 context
0:00:00.631649700 29460 000001E07A782CC0 DEBUG glcontext gstglcontext_wgl.c:235:gst_gl_context_wgl_create_context:<glcontextwgl0> trying to create a GL 4.4 context
0:00:00.650484600 29460 000001E07A782CC0 DEBUG glcontext gstglcontext_wgl.c:235:gst_gl_context_wgl_create_context:<glcontextwgl0> trying to create a GL 4.3 context
0:00:00.669332300 29460 000001E07A782CC0 DEBUG glcontext gstglcontext_wgl.c:235:gst_gl_context_wgl_create_context:<glcontextwgl0> trying to create a GL 4.2 context
0:00:00.687633700 29460 000001E07A782CC0 DEBUG glcontext gstglcontext_wgl.c:235:gst_gl_context_wgl_create_context:<glcontextwgl0> trying to create a GL 4.1 context
0:00:00.706444500 29460 000001E07A782CC0 DEBUG glcontext gstglcontext_wgl.c:235:gst_gl_context_wgl_create_context:<glcontextwgl0> trying to create a GL 4.0 context
0:00:00.725763400 29460 000001E07A782CC0 DEBUG glcontext gstglcontext_wgl.c:235:gst_gl_context_wgl_create_context:<glcontextwgl0> trying to create a GL 3.3 context
0:00:00.745413200 29460 000001E07A782CC0 DEBUG glcontext gstglcontext_wgl.c:235:gst_gl_context_wgl_create_context:<glcontextwgl0> trying to create a GL 3.2 context
0:00:00.781065300 29460 000001E07A782CC0 WARN glcontext gstglcontext.c:1326:gst_gl_context_create_thread:<glcontextwgl0> Failed to create context
0:00:00.781358600 29460 000001E076862100 INFO glcontext gstglcontext.c:1079:gst_gl_context_create:<glcontextwgl0> gl thread created
0:00:00.781584200 29460 000001E076862100 DEBUG glcontext gstglcontext.c:746:gst_gl_context_finalize:<glcontextwgl0> End of finalize
0:00:00.781787700 29460 000001E076862100 WARN glbasefilter gstglbasefilter.c:608:gst_gl_base_filter_find_gl_context_unlocked:<gluploadelement0> error: failed to share contexts through wglShareLists 0xaa
0:00:00.782145700 29460 000001E076862100 INFO glcontext gstglcontext.c:349:gst_gl_context_new: creating a context for display <gldisplay0>, user choice:(null)
0:00:00.782381300 29460 000001E076862100 DEBUG glcontext gstglcontext.c:383:gst_gl_context_new:<glcontextwgl1> Done creating context for display <gldisplay0> (user_choice:(null))
0:00:00.782632900 29460 000001E076862100 DEBUG glcontext gstglcontext.c:1058:gst_gl_context_create:<glcontextwgl1> other_context:<glwrappedcontext0>
0:00:00.782921300 29460 000001E076862100 INFO glwindow gstglwindow.c:295:gst_gl_window_new: creating a window, user choice:(null)
0:00:00.783246300 29460 000001E076862100 DEBUG glcontext gstglcontext.c:956:gst_gl_context_set_window:<glcontextwgl1> window:<glwindowwin32-1>
0:00:00.783815200 29460 000001E07A782D00 DEBUG glcontext gstglcontext.c:1227:gst_gl_context_create_thread:<glcontextwgl1> Creating thread
0:00:00.784130000 29460 000001E07A782D00 FIXME glcontext gstglcontext.c:2041:gst_gl_wrapped_context_get_config:<glwrappedcontext0> wrapped context could not retrieve config. The application may be missing a call to gst_gl_context_fill_info() or the specific platform implemention is not implemented for retrieving the config from a wrapped OpenGL context.
thread 'main' panicked at examples\src\bin\..\glupload.rs:755:44:
called `Result::unwrap()` on an `Err` value: Received error from /GstPipeline:pipeline0/GstGLSinkBin:glsinkbin0/GstGLUploadElement:gluploadelement0: failed to share contexts through wglShareLists 0xaa (debug: Some("../gst-libs/gst/gl/gstglbasefilter.c(608): gst_gl_base_filter_find_gl_context_unlocked (): /GstPipeline:pipeline0/GstGLSinkBin:glsinkbin0/GstGLUploadElement:gluploadelement0"))
This happens because the context is made "current" inside
the `winit` loop before asynchronous GL initialization inside
GStreamer creates a shared context for contexts replied to
`NeedContext("gst.gl.app_context")`. `wglShareLists()` requires neither
context to be current on separate threads. As we have a `Surface` on
the `glutin` side, we're not uncurrenting it anymore, and instead want
to perform GStreamer initialization up-front without a thread, or on a
separate `GLContext`.
One way to prevent GStreamer from creating yet another context on top
of our wrapped context asynchronously, is by creating a new shared GL
context based on our wrapped (WGL) context ourselves.
By adding that context to `GLDisplay` (that we provide in the
relevant `gst.gl.GLDisplay` context query) instead of via the
`gst.gl.app_context` `NeedContext` query, the underlying initialization
code no longer attempts to create a shared context because it
will use the one from `GLDisplay` directly (specifically in e.g.
`gst_gl_base_filter_find_gl_context_unlocked()`).
The preferred way however is to reply this new shared context to
a `Query` for the `gst.gl.local_context` context, which arbitrary
applications can achieve by inserting a pad probe on one of the pads
in the pipeline. GL elements and functions like the one mentioned above
call into `gst_gl_query_local_gl_context()` which performs this query in
both directions, before reading contexts from `GLDisplay` or ultimately
sending a `NeedContext` message outlined above.
With this patch the initialization flow becomes clear from the logs,
where the above lines that will call `wglShareLists()` are now called
directly when `gl_context.create(wrapped_context)` is called in our
Rust code.
In theory, since `GLContext` tracks whether it is current and on
which thread, the upsteam source should emit an error of sorts when
`wglShareLists()` is called on a thread where this `other_context` in
`gst_gl_context_create(_thread)` was not yet current, to not make such
mistakes go unnoticed as most drivers (i.e. AMD's) seem to not make an
issue out of it.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/merge_requests/1486>
This commit is contained in:
Marijn Suijten
parent
75095b03ec
commit
f5bafe5a07
1 changed files with 78 additions and 77 deletions
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@ -14,7 +14,6 @@ use std::{
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};
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use anyhow::{Context, Result};
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use derive_more::derive::{Display, Error};
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use glutin::{
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config::GetGlConfig as _,
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context::AsRawContext as _,
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@ -22,18 +21,10 @@ use glutin::{
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prelude::*,
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};
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use glutin_winit::GlWindow as _;
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use gst::element_error;
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use gst::{element_error, PadProbeReturn, PadProbeType, QueryViewMut};
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use gst_gl::prelude::*;
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use raw_window_handle::HasRawWindowHandle as _;
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#[derive(Debug, Display, Error)]
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#[display("Received error from {src}: {error} (debug: {debug:?})")]
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struct ErrorMessage {
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src: glib::GString,
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error: glib::Error,
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debug: Option<glib::GString>,
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}
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#[rustfmt::skip]
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static VERTICES: [f32; 20] = [
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1.0, 1.0, 0.0, 1.0, 0.0,
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@ -325,17 +316,16 @@ fn load(gl_display: &impl glutin::display::GlDisplay) -> Gl {
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#[derive(Debug)]
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enum Message {
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Frame(gst_video::VideoInfo, gst::Buffer),
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BusEvent,
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BusMessage(gst::Message),
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}
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pub(crate) struct App {
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pipeline: gst::Pipeline,
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appsink: gst_app::AppSink,
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bus: gst::Bus,
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event_loop: winit::event_loop::EventLoop<Message>,
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window: Option<winit::window::Window>,
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not_current_gl_context: Option<glutin::context::NotCurrentContext>,
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shared_context: gst_gl::GLContext,
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glutin_context: gst_gl::GLContext,
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}
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impl App {
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@ -471,60 +461,82 @@ impl App {
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handler => anyhow::bail!("Unsupported platform: {handler:?}."),
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};
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let shared_context = unsafe {
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let glutin_context = unsafe {
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gst_gl::GLContext::new_wrapped(&gst_gl_display, raw_gl_context, platform, api)
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}
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.context("Couldn't wrap GL context")?;
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let gl_context = shared_context.clone();
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{
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// Make a new context that isn't the wrapped glutin context so that it can be made
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// current on a new "gstglcontext" thread (see `gst_gl_context_create_thread()`), while
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// the wrapped glutin context is made current on the winit event loop thread (this main
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// thread).
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let shared_context = gst_gl::GLContext::new(&gst_gl_display);
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shared_context
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.create(Some(&glutin_context))
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.context("Couldn't share wrapped Glutin GL context with new GL context")?;
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// Return the shared `GLContext` out of a pad probe for "gst.gl.local_context" to
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// make the underlying pipeline use it directly, instead of creating a new GL context
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// that is *shared* with the resulting context from a context `Query` (among other
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// elements) or `NeedContext` bus message for "gst.gl.app_context", as documented for
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// `gst_gl_ensure_element_data()`.
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//
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// On Windows, such context sharing calls `wglShareLists()` which fails on certain
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// drivers when one of the contexts is already current on another thread. This would
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// happen because the pipeline and specifically the aforementioned "gstglcontext"
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// thread would be initialized asynchronously from the winit loop which makes our glutin
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// context current. By calling `GLContext::create()` above, context sharing happens
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// directly.
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//
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// An alternative approach would be using `gst_gl::GLDisplay::add_context()` to store
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// the context inside `GLDisplay`, but the pad probe takes precedence.
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// While the pad probe could be installed anywhere, it makes logical sense to insert it
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// on the appsink where the images are extracted and displayed to a window via the same
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// GL contexts.
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appsink
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.static_pad("sink")
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.unwrap()
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.add_probe(PadProbeType::QUERY_DOWNSTREAM, move |pad, probe_info| {
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if let Some(q) = probe_info.query_mut() {
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if let QueryViewMut::Context(cq) = q.view_mut() {
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if gst_gl::functions::gl_handle_context_query(
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&pad.parent_element().unwrap(),
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cq,
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Some(&gst_gl_display),
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Some(&shared_context),
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None::<&gst_gl::GLContext>,
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) {
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return PadProbeReturn::Handled;
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}
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}
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}
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PadProbeReturn::Ok
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})
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.unwrap();
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}
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let event_proxy = event_loop.create_proxy();
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#[allow(clippy::single_match)]
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bus.set_sync_handler(move |_, msg| {
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match msg.view() {
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gst::MessageView::NeedContext(ctxt) => {
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let context_type = ctxt.context_type();
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if context_type == *gst_gl::GL_DISPLAY_CONTEXT_TYPE {
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if let Some(el) =
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msg.src().map(|s| s.downcast_ref::<gst::Element>().unwrap())
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bus.set_sync_handler(move |_bus, msg| {
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if let Err(e) = event_proxy
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// Forward all messages to winit's event loop
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.send_event(Message::BusMessage(msg.to_owned()))
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{
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let context = gst::Context::new(context_type, true);
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context.set_gl_display(&gst_gl_display);
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el.set_context(&context);
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}
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}
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if context_type == "gst.gl.app_context" {
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if let Some(el) =
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msg.src().map(|s| s.downcast_ref::<gst::Element>().unwrap())
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{
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let mut context = gst::Context::new(context_type, true);
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{
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let context = context.get_mut().unwrap();
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let s = context.structure_mut();
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s.set("context", &gl_context);
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}
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el.set_context(&context);
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}
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}
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}
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_ => (),
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}
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if let Err(e) = event_proxy.send_event(Message::BusEvent) {
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eprintln!("Failed to send BusEvent to event proxy: {e}")
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}
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gst::BusSyncReply::Pass
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gst::BusSyncReply::Drop
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});
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Ok(App {
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pipeline,
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appsink,
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bus,
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event_loop,
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window,
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not_current_gl_context: Some(not_current_gl_context),
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shared_context,
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glutin_context,
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})
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}
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@ -658,28 +670,20 @@ impl App {
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}
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}
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fn handle_messages(bus: &gst::Bus) -> Result<()> {
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/// Should be called from within the event loop
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fn handle_message(msg: gst::Message) {
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use gst::MessageView;
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for msg in bus.iter() {
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match msg.view() {
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MessageView::Eos(..) => break,
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MessageView::Error(err) => {
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return Err(ErrorMessage {
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src: msg
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// Only handle error messages by panicking, to hard-stop the event loop
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if let MessageView::Error(err) = msg.view() {
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let src = msg
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.src()
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.map(|s| s.path_string())
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.unwrap_or_else(|| glib::GString::from("UNKNOWN")),
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error: err.error(),
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debug: err.debug(),
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.unwrap_or_else(|| glib::GString::from("UNKNOWN"));
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let error = err.error();
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let debug = err.debug();
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panic!("Received error from {src}: {error} (debug: {debug:?})");
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}
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.into());
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}
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_ => (),
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}
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}
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Ok(())
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}
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}
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@ -688,11 +692,10 @@ pub(crate) fn main_loop(app: App) -> Result<()> {
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let App {
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pipeline,
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bus,
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event_loop,
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mut window,
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mut not_current_gl_context,
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shared_context,
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glutin_context,
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..
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} = app;
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@ -751,9 +754,7 @@ pub(crate) fn main_loop(app: App) -> Result<()> {
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}
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}
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// Handle all pending messages when we are awaken by set_sync_handler
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winit::event::Event::UserEvent(Message::BusEvent) => {
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App::handle_messages(&bus).unwrap();
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}
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winit::event::Event::UserEvent(Message::BusMessage(msg)) => App::handle_message(msg),
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winit::event::Event::Resumed => {
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let not_current_gl_context = not_current_gl_context
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.take()
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@ -781,9 +782,9 @@ pub(crate) fn main_loop(app: App) -> Result<()> {
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// Tell GStreamer that the context has been made current (for borrowed contexts,
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// this does not try to make it current again)
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shared_context.activate(true).unwrap();
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glutin_context.activate(true).unwrap();
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shared_context
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glutin_context
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.fill_info()
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.expect("Couldn't fill context info");
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@ -812,7 +813,7 @@ pub(crate) fn main_loop(app: App) -> Result<()> {
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if let Some((gl, gl_context, gl_surface)) = &running_state {
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if let Some(frame) = curr_frame.as_ref() {
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let sync_meta = frame.buffer().meta::<gst_gl::GLSyncMeta>().unwrap();
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sync_meta.wait(&shared_context);
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sync_meta.wait(&glutin_context);
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if let Ok(texture) = frame.texture_id(0) {
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gl.draw_frame(texture as gl::types::GLuint);
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}
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