/* * GStreamer * Copyright (C) 2018 Carlos Rafael Giani * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Library General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Library General Public License for more details. * * You should have received a copy of the GNU Library General Public * License along with this library; if not, write to the * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, * Boston, MA 02110-1301, USA. */ #include #include "../gstgl_fwd.h" #include #include #include "gstgldisplay_gbm.h" #include "gstglwindow_gbm_egl.h" #include "gstgl_gbm_utils.h" #include "../gstglwindow_private.h" #define GST_CAT_DEFAULT gst_gl_window_debug #define GST_GL_WINDOW_GBM_EGL_GET_PRIVATE(obj) (G_TYPE_INSTANCE_GET_PRIVATE ((obj), \ GST_TYPE_GL_WINDOW_GBM_EGL, GstGLWindowGBMEGLPrivate)) G_DEFINE_TYPE (GstGLWindowGBMEGL, gst_gl_window_gbm_egl, GST_TYPE_GL_WINDOW); static guintptr gst_gl_window_gbm_egl_get_window_handle (GstGLWindow * window); static guintptr gst_gl_window_gbm_egl_get_display (GstGLWindow * window); static void gst_gl_window_gbm_egl_set_window_handle (GstGLWindow * window, guintptr handle); static void gst_gl_window_gbm_egl_close (GstGLWindow * window); static void gst_gl_window_gbm_egl_draw (GstGLWindow * window); static gboolean gst_gl_window_gbm_init_surface (GstGLWindowGBMEGL * window_egl); static void gst_gl_window_gbm_egl_cleanup (GstGLWindowGBMEGL * window_egl); static void gst_gl_window_gbm_egl_class_init (GstGLWindowGBMEGLClass * klass) { GstGLWindowClass *window_class = (GstGLWindowClass *) klass; window_class->get_window_handle = GST_DEBUG_FUNCPTR (gst_gl_window_gbm_egl_get_window_handle); window_class->get_display = GST_DEBUG_FUNCPTR (gst_gl_window_gbm_egl_get_display); window_class->set_window_handle = GST_DEBUG_FUNCPTR (gst_gl_window_gbm_egl_set_window_handle); window_class->close = GST_DEBUG_FUNCPTR (gst_gl_window_gbm_egl_close); window_class->draw = GST_DEBUG_FUNCPTR (gst_gl_window_gbm_egl_draw); /* TODO: add support for set_render_rectangle (assuming this functionality * is possible with libdrm/gbm) */ } static void gst_gl_window_gbm_egl_init (GstGLWindowGBMEGL * window_gbm) { window_gbm->gbm_surf = NULL; window_gbm->current_bo = NULL; window_gbm->prev_bo = NULL; window_gbm->waiting_for_flip = 0; } static guintptr gst_gl_window_gbm_egl_get_window_handle (GstGLWindow * window) { return (guintptr) GST_GL_WINDOW_GBM_EGL (window)->gbm_surf; } static guintptr gst_gl_window_gbm_egl_get_display (GstGLWindow * window) { return gst_gl_display_get_handle (window->display); } static void gst_gl_window_gbm_egl_set_window_handle (G_GNUC_UNUSED GstGLWindow * window, G_GNUC_UNUSED guintptr handle) { /* TODO: Currently, it is unclear how to use external GBM buffer objects, * since it is not defined how this would work together with DRM page flips */ } static void gst_gl_window_gbm_egl_close (GstGLWindow * window) { GstGLWindowGBMEGL *window_egl = GST_GL_WINDOW_GBM_EGL (window); gst_gl_window_gbm_egl_cleanup (window_egl); GST_GL_WINDOW_CLASS (gst_gl_window_gbm_egl_parent_class)->close (window); } static void _page_flip_handler (G_GNUC_UNUSED int fd, G_GNUC_UNUSED unsigned int frame, G_GNUC_UNUSED unsigned int sec, G_GNUC_UNUSED unsigned int usec, void *data) { /* If we reach this point, it means the page flip has been completed. * Signal this by clearing the flag so the poll() loop in draw_cb() * can exit. */ int *waiting_for_flip = data; *waiting_for_flip = 0; } static void draw_cb (gpointer data) { GstGLWindowGBMEGL *window_egl = data; GstGLWindow *window = GST_GL_WINDOW (window_egl); GstGLContext *context = gst_gl_window_get_context (window); GstGLContextClass *context_class = GST_GL_CONTEXT_GET_CLASS (context); GstGLDisplayGBM *display = (GstGLDisplayGBM *) window->display; struct gbm_bo *next_bo; GstGLDRMFramebuffer *framebuf; int ret; drmEventContext evctx = { .version = DRM_EVENT_CONTEXT_VERSION, .page_flip_handler = _page_flip_handler, }; struct pollfd pfd = { .fd = display->drm_fd, .events = POLLIN, .revents = 0, }; /* Rendering, page flipping etc. are connect this way: * * The frames are stored in buffer objects (BOs). Inside the eglSwapBuffers() * call, GBM creates new BOs if necessary. BOs can be "locked" for rendering, * meaning that EGL cannot use them as a render target. If all available * BOs are locked, the GBM code inside eglSwapBuffers() creates a new, * unlocked one. We make use of this to implement triple buffering. * * There are 3 BOs in play: * * * next_bo: The BO we just rendered into. * * current_bo: The currently displayed BO. * * prev_bo: The previously displayed BO. * * current_bo and prev_bo are involed in page flipping. next_bo is not. * * Once rendering is done, the next_bo is retrieved and locked. Then, we * wait until any ongoing page flipping finishes. Once it does, the * current_bo is displayed on screen, and the prev_bo isn't anymore. At * this point, it is safe to release the prev_bo, which unlocks it and * makes it available again as a render target. Then we initiate the * next page flipping; this time, we flip to next_bo. At that point, * next_bo becomes current_bo, and current_bo becomes prev_bo. */ /* * There is a special case at the beginning. There is no currently * displayed BO at first, so we create an empty one to get the page * flipping cycle going. Also, we use this first BO for setting up * the CRTC. */ if (window_egl->current_bo == NULL) { /* Call eglSwapBuffers() to create a BO. */ context_class->swap_buffers (context); /* Lock the BO so we get our first current_bo. */ window_egl->current_bo = gbm_surface_lock_front_buffer (window_egl->gbm_surf); framebuf = gst_gl_gbm_drm_fb_get_from_bo (window_egl->current_bo); /* Configure CRTC to show this first BO. */ ret = drmModeSetCrtc (display->drm_fd, display->crtc_id, framebuf->fb_id, 0, 0, &(display->drm_mode_connector->connector_id), 1, display->drm_mode_info); if (ret != 0) { GST_ERROR ("Could not set DRM CRTC: %s (%d)", g_strerror (errno), errno); /* XXX: it is not possible to communicate the error to the pipeline */ return; } } /* Do the actual drawing */ if (window->draw) window->draw (window->draw_data); /* Let the context class call eglSwapBuffers(). As mentioned above, * if necessary, this function creates a new unlocked framebuffer * that can be used as render target. */ context_class->swap_buffers (context); gst_object_unref (context); next_bo = gbm_surface_lock_front_buffer (window_egl->gbm_surf); framebuf = gst_gl_gbm_drm_fb_get_from_bo (next_bo); GST_LOG ("rendered new frame into bo %p", (gpointer) next_bo); /* Wait until any ongoing page flipping is done. After this is done, * prev_bo is no longer involved in any page flipping, and can be * safely released. */ while (window_egl->waiting_for_flip) { ret = poll (&pfd, 1, -1); if (ret < 0) { if (errno == EINTR) GST_DEBUG ("Signal caught during poll() call"); else GST_ERROR ("poll() failed: %s (%d)", g_strerror (errno), errno); /* XXX: it is not possible to communicate errors and interruptions * to the pipeline */ return; } drmHandleEvent (display->drm_fd, &evctx); } GST_LOG ("now showing bo %p", (gpointer) (window_egl->current_bo)); /* Release prev_bo, since it is no longer shown on screen. */ if (G_LIKELY (window_egl->prev_bo != NULL)) { gbm_surface_release_buffer (window_egl->gbm_surf, window_egl->prev_bo); GST_LOG ("releasing bo %p", (gpointer) (window_egl->prev_bo)); } /* Presently, current_bo is shown on screen. Schedule the next page * flip, this time flip to next_bo. The flip happens asynchronously, so * we can continue and render etc. in the meantime. */ window_egl->waiting_for_flip = 1; ret = drmModePageFlip (display->drm_fd, display->crtc_id, framebuf->fb_id, DRM_MODE_PAGE_FLIP_EVENT, &(window_egl->waiting_for_flip)); if (ret != 0) { /* NOTE: According to libdrm sources, the page is _not_ * considered flipped if drmModePageFlip() reports an error, * so we do not update the priv->current_bo pointer here */ GST_ERROR ("Could not initialize GBM surface"); /* XXX: it is not possible to communicate the error to the pipeline */ return; } /* At this point, we relabel the current_bo as the prev_bo. * This may not actually be the case yet, but it will be soon - latest * when the wait loop above finishes. * Also, next_bo becomes current_bo. */ window_egl->prev_bo = window_egl->current_bo; window_egl->current_bo = next_bo; } static void gst_gl_window_gbm_egl_draw (GstGLWindow * window) { gst_gl_window_send_message (window, (GstGLWindowCB) draw_cb, window); } static gboolean gst_gl_window_gbm_init_surface (GstGLWindowGBMEGL * window_egl) { /* NOTE: This function cannot be called in the open() vmethod * since context_egl->egl_display and context_egl->egl_config * must have been set to valid values at this point, and open() * is called _before_ these are set. * Also, eglInitialize() is called _after_ the open() vmethod, * which means that the return value of gbm_surface_create() * contains some function pointers that are set to NULL and * shouldn't be. This is because Mesa's eglInitialize() loads * the DRI2 driver and the relevant functions aren't available * until then. * * Therefore, this function is called instead inside * gst_gl_window_gbm_egl_create_window(), which in turn is * called inside gst_gl_context_egl_create_context(). */ GstGLWindow *window = GST_GL_WINDOW (window_egl); GstGLDisplayGBM *display = (GstGLDisplayGBM *) window->display; drmModeModeInfo *drm_mode_info = display->drm_mode_info; GstGLContext *context = gst_gl_window_get_context (window); GstGLContextEGL *context_egl = GST_GL_CONTEXT_EGL (context); EGLint gbm_format; /* With GBM-based EGL displays and configs, the native visual ID * is a GBM pixel format. */ if (!eglGetConfigAttrib (context_egl->egl_display, context_egl->egl_config, EGL_NATIVE_VISUAL_ID, &gbm_format)) { GST_ERROR ("eglGetConfigAttrib failed: %s", gst_egl_get_error_string (eglGetError ())); return FALSE; } /* Create a GBM surface that shall contain the BOs we are * going to render into. */ window_egl->gbm_surf = gbm_surface_create (display->gbm_dev, drm_mode_info->hdisplay, drm_mode_info->vdisplay, gbm_format, GBM_BO_USE_SCANOUT | GBM_BO_USE_RENDERING); gst_gl_window_resize (window, drm_mode_info->hdisplay, drm_mode_info->vdisplay); GST_DEBUG ("Successfully created GBM surface"); return TRUE; } static void gst_gl_window_gbm_egl_cleanup (GstGLWindowGBMEGL * window_egl) { if (window_egl->gbm_surf != NULL) { if (window_egl->current_bo != NULL) { gbm_surface_release_buffer (window_egl->gbm_surf, window_egl->current_bo); window_egl->current_bo = NULL; } gbm_surface_destroy (window_egl->gbm_surf); window_egl->gbm_surf = NULL; } } /* Must be called in the gl thread */ GstGLWindowGBMEGL * gst_gl_window_gbm_egl_new (GstGLDisplay * display) { GstGLWindowGBMEGL *window_egl; if ((gst_gl_display_get_handle_type (display) & GST_GL_DISPLAY_TYPE_GBM) == 0) /* we require a GBM display to create windows */ return NULL; window_egl = g_object_new (GST_TYPE_GL_WINDOW_GBM_EGL, NULL); return window_egl; } gboolean gst_gl_window_gbm_egl_create_window (GstGLWindowGBMEGL * window_egl) { return gst_gl_window_gbm_init_surface (window_egl); }