Hey!
Truly, idk if this is the right sort of place to ask, but it seems to be the most appropriate (I was redirected here from the dead dri-egl@lists.freedesktop.org mailing list). Feel free to point me somewhere else if this isn't where I should be asking this question!
I'm working on an X11 compositor using EGL, and I'm creating an EGLImage from a native pixmap something like this:
xcb_pixmap_t pixmap = xcb_generate_id(connection); xcb_void_cookie_t cookie = xcb_composite_name_window_pixmap_checked(connection, win, pixmap);
if (xcb_request_check(connection, cookie)) { goto error; }
EGLImage image = eglCreateImageKHR(egl_display, EGL_NO_CONTEXT, EGL_NATIVE_PIXMAP_KHR, (EGLClientBuffer) (intptr_t) pixmap, NULL);
(Using the EGL_KHR_image_pixmap extension: https://www.khronos.org/registry/EGL/extensions/KHR/EGL_KHR_image_base.txt)
Which I'm then binding to a texture a little something like this:
GLuint texture; glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_EXTERNAL_OES, texture); glEGLImageTargetTexture2DOES(GL_TEXTURE_EXTERNAL_OES, image);
(Using the OES_EGL_image_external extension: https://www.khronos.org/registry/OpenGL/extensions/OES/OES_EGL_image_externa...) (Naturally my actual code isn't actually generating a new texture each time; I'm showing it as such in the interest of simplicity.)
I'm doing it with OES_EGL_image_external because EGL_BIND_TO_TEXTURE_RGB(A) seems to have been deprecated by NVIDIA (?): https://forums.developer.nvidia.com/t/egl-bind-to-texture-rgba-attribute-alw... This isn't reflected in the Khronos EGL registry for whatever reason so I'm unsure.
Anyway, this all works fine & dandy, except that eglCreateImageKHR is sometimes *really* slow. Like, it works fine mostly, but with some windows (especially GLX windows), there's often times a multi-frame delay. Since AFAICT image creation can only be done on the main OpenGL thread, it slows down all the other animations and whatnot of my compositor, which is very much unideal.
I've tried churning my way through the source code of various compositors (well, I couldn't really find many which used EGL specifically, but GLX has a similar problem with glXBindTexImageEXT), and, aside from the ones which are too opaque for me to understand, I don't really see how they're doing things much differently. Obviously however it's something I'm doing wrong/missing, because those other compositors are perfectly speedy.
I'd be very grateful if somebody could shed a little light on this issue! Have a wonderful day!