<div dir="ltr">I'll be honest, thus far I've simply copied over <a href="https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/blob/74557132e17e24677b4f60fcffe32adec4de60c7/examples/src/glupload.rs">examples/src/glupload.rs</a> and have been hacking away at it, in an attempt to understand the logic and understand the gstreamer_gl/glutin workflow, so I have nothing that would really make sense even as a draft MR. But there's a couple main points of glupload that are throwing me off.<div> <div>So, as a brief summary, I'm trying to replicate <a href="https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/blob/main/examples/src/glupload.rs">examples/src/glwindow.rs</a>, which simply creates a glupload::App(None) (<a href="https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/blob/74557132e17e24677b4f60fcffe32adec4de60c7/examples/src/bin/glwindow.rs#L11">L11</a>) and runs glupload::main_loop in that App (<a href="https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/blob/74557132e17e24677b4f60fcffe32adec4de60c7/examples/src/bin/glwindow.rs#L12">L12</a>). So my troubles come from trying to make <a href="https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/blob/74557132e17e24677b4f60fcffe32adec4de60c7/examples/src/glupload.rs">examples/src/glupload.rs</a> support Windows (WGL).</div></div><div> </div><div>With that said, my troubles start in <a href="https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/blob/74557132e17e24677b4f60fcffe32adec4de60c7/examples/src/glupload.rs#L330" style="font-family:monospace">glupload::App::new</a>, specifically at <a href="https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/blob/74557132e17e24677b4f60fcffe32adec4de60c7/examples/src/glupload.rs#L350">L350</a>. Here glupload fails by design if the platform is not linux. This is easy to fix, but within this if statement, glupload matches the raw gl context handle, provided by glutin, checking only for EGL and GLX, then creates a <a href="https://gstreamer.pages.freedesktop.org/gstreamer-rs/stable/latest/docs/gstreamer_gl/struct.GLDisplay.html" style="font-family:monospace">GLDisplay</a> using <a href="https://gstreamer.pages.freedesktop.org/gstreamer-rs/stable/latest/docs/gstreamer_gl_egl/struct.GLDisplayEGL.html#method.from_gl_display">gstreamer_gl_egl::GLDisplayEGL::</a><a href="https://gstreamer.pages.freedesktop.org/gstreamer-rs/stable/latest/docs/gstreamer_gl_egl/struct.GLDisplayEGL.html#method.from_gl_display">with_egl_display</a>, <a href="https://gstreamer.pages.freedesktop.org/gstreamer-rs/stable/latest/docs/gstreamer_gl_wayland/struct.GLDisplayWayland.html#method.with_display">gstreamer_gl_wayland::GLDisplayWayland::</a><a href="https://gstreamer.pages.freedesktop.org/gstreamer-rs/stable/latest/docs/gstreamer_gl_wayland/struct.GLDisplayWayland.html#method.with_display">with_display</a>, or <a href="https://gstreamer.pages.freedesktop.org/gstreamer-rs/stable/latest/docs/gstreamer_gl_x11/struct.GLDisplayX11.html#method.with_display">gstreamer_gl_x11::GLDisplayX11::</a><a href="https://gstreamer.pages.freedesktop.org/gstreamer-rs/stable/latest/docs/gstreamer_gl_x11/struct.GLDisplayX11.html#method.with_display">with_display</a>, depending on context. Lastly, it creates a wrapped GLContext (<a href="https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/blob/74557132e17e24677b4f60fcffe32adec4de60c7/examples/src/glupload.rs#L408">L408</a>), using the GLDisplay created in the previous step. As far as I can tell, this process handles linking the gl context provided by glutin to a GLContext and linking that with the GLDisplay created in the egl/wayland/x11 functions. It's this linking that I can't seem to replicate on Windows. Since there's no equivalent functions for WGL, I'm somewhat left in the dark here.</div><div> </div><div>The most progress I've managed to make here is simply creating a <a href="https://gstreamer.pages.freedesktop.org/gstreamer-rs/stable/latest/docs/gstreamer_gl/struct.GLDisplay.html#method.new">new </a><a href="https://gstreamer.pages.freedesktop.org/gstreamer-rs/stable/latest/docs/gstreamer_gl/struct.GLDisplay.html#method.new" style="font-family:monospace">GLDisplay</a> in place of the GLDisplayXXX::with_display functions, creating the wrapped GLContext in the same way as <a href="https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/blob/74557132e17e24677b4f60fcffe32adec4de60c7/examples/src/glupload.rs#L408" style="font-family:arial,sans-serif">L408</a>:</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">// <a href="https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/blob/74557132e17e24677b4f60fcffe32adec4de60c7/examples/src/glupload.rs#L356">L356</a></blockquote><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">let api = App::map_gl_api(windowed_context.get_api()); </blockquote><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> </blockquote><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> // replace <a href="https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/blob/74557132e17e24677b4f60fcffe32adec4de60c7/examples/src/glupload.rs#L358-406">L358-406</a> with the following</blockquote><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">let gl_context = if let RawHandle::Wgl(ctx) = unsafe { windowed_context.raw_handle() } { ctx as usize } else { panic!("Expected WGL!"); }; </blockquote><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">// leak to ensure the display doesn't get dropped</blockquote><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">let gl_display: &'static gstreamer_gl::GLDisplay = Box::leak(Box::new(gstreamer_gl::GLDisplay::new()));</blockquote><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">let platform = gstreamer_gl::GLPlatform::WGL;</blockquote><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> </blockquote><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> // <a href="https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/blob/74557132e17e24677b4f60fcffe32adec4de60c7/examples/src/glupload.rs#L408">L408</a></blockquote><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">shared_context = unsafe { gst_gl::GLContext::new_wrapped(gl_display, gl_context, platform, api) } .unwrap();</blockquote><div> </div><div>which compiles and makes it past App::new, but then fails in main_loop with the following error:</div><div> </div><div>failed to share contexts through wglShareLists 0xaa', <a href="https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/blob/74557132e17e24677b4f60fcffe32adec4de60c7/examples/src/glupload.rs#L697">src\glupload.rs:697:44</a> </div><div> </div><div>My intuition tells me that the GLDisplay and gl context aren't getting properly linked, but I might be wrong. Anyway, hopefully this is helpful, and thanks for all your help so far!</div></div>