[mutter/gbsneto/dmabuf-screencast: 7/8] monitor-stream-src: Export DMA buffers for the current onscreen

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 9fda9106aff96cdc5fdfaa056dbd7a08026a4aa5
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Mon Dec 9 10:11:51 2019 -0300

    monitor-stream-src: Export DMA buffers for the current onscreen
    
    Add the vfunc overrides that actually consume the new CoglOnscreen
    API, and cogl_freamebuffer_flush() as well.
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1086

 src/backends/meta-screen-cast-monitor-stream-src.c | 84 ++++++++++++++++++++++
 1 file changed, 84 insertions(+)
---
diff --git a/src/backends/meta-screen-cast-monitor-stream-src.c 
b/src/backends/meta-screen-cast-monitor-stream-src.c
index 5d9dadc8c..501ada7a1 100644
--- a/src/backends/meta-screen-cast-monitor-stream-src.c
+++ b/src/backends/meta-screen-cast-monitor-stream-src.c
@@ -358,6 +358,86 @@ meta_screen_cast_monitor_stream_src_record_frame (MetaScreenCastStreamSrc *src,
   return TRUE;
 }
 
+static CoglOnscreenDmabufHandle *
+meta_screen_cast_monitor_stream_src_capture_dmabuf (MetaScreenCastStreamSrc *src)
+{
+  MetaScreenCastMonitorStreamSrc *monitor_src =
+    META_SCREEN_CAST_MONITOR_STREAM_SRC (src);
+  MetaBackend *backend = get_backend (monitor_src);
+  MetaRenderer *renderer = meta_backend_get_renderer (backend);
+  MetaRendererView *view;
+  CoglFramebuffer *onscreen;
+  MetaMonitor *monitor;
+  MetaLogicalMonitor *logical_monitor;
+  g_autoptr (GError) error = NULL;
+  CoglOnscreenDmabufHandle *dmabuf_handle;
+
+  monitor = get_monitor (monitor_src);
+  logical_monitor = meta_monitor_get_logical_monitor (monitor);
+
+  view = meta_renderer_get_view_from_logical_monitor (renderer, logical_monitor);
+  if (!view)
+    return NULL;
+
+  onscreen = clutter_stage_view_get_onscreen (CLUTTER_STAGE_VIEW (view));
+  if (!onscreen)
+    return NULL;
+
+  dmabuf_handle = cogl_onscreen_capture_dmabuf (COGL_ONSCREEN (onscreen),
+                                                &error);
+
+  if (error)
+    {
+      g_debug ("Error exporting DMA buffer handle: %s", error->message);
+      return NULL;
+    }
+
+  return dmabuf_handle;
+}
+
+static gboolean
+meta_screen_cast_monitor_stream_src_blit_to_framebuffer (MetaScreenCastStreamSrc *src,
+                                                         CoglFramebuffer         *framebuffer)
+{
+  MetaScreenCastMonitorStreamSrc *monitor_src =
+    META_SCREEN_CAST_MONITOR_STREAM_SRC (src);
+  MetaBackend *backend = get_backend (monitor_src);
+  MetaRenderer *renderer = meta_backend_get_renderer (backend);
+  MetaRendererView *view;
+  CoglFramebuffer *onscreen;
+  MetaMonitor *monitor;
+  MetaLogicalMonitor *logical_monitor;
+  g_autoptr (GError) error = NULL;
+
+  monitor = get_monitor (monitor_src);
+  logical_monitor = meta_monitor_get_logical_monitor (monitor);
+  view = meta_renderer_get_view_from_logical_monitor (renderer, logical_monitor);
+  onscreen = clutter_stage_view_get_onscreen (CLUTTER_STAGE_VIEW (view));
+
+  cogl_framebuffer_clear4f (framebuffer,
+                            COGL_BUFFER_BIT_COLOR,
+                            0.f, 0.f, 0.f, 1.f);
+
+  cogl_blit_framebuffer (onscreen,
+                         framebuffer,
+                         0, 0,
+                         0, 0,
+                         cogl_framebuffer_get_width (framebuffer),
+                         cogl_framebuffer_get_height (framebuffer),
+                         &error);
+
+  cogl_framebuffer_flush (framebuffer);
+
+  if (error)
+    {
+      g_warning ("Error blitting onscreen into DMABuf framebuffer: %s",
+                 error->message);
+      return FALSE;
+    }
+
+  return TRUE;
+}
+
 static void
 meta_screen_cast_monitor_stream_src_set_cursor_metadata (MetaScreenCastStreamSrc *src,
                                                          struct spa_meta_cursor  *spa_meta_cursor)
@@ -483,6 +563,10 @@ meta_screen_cast_monitor_stream_src_class_init (MetaScreenCastMonitorStreamSrcCl
   src_class->enable = meta_screen_cast_monitor_stream_src_enable;
   src_class->disable = meta_screen_cast_monitor_stream_src_disable;
   src_class->record_frame = meta_screen_cast_monitor_stream_src_record_frame;
+  src_class->capture_dmabuf =
+    meta_screen_cast_monitor_stream_src_capture_dmabuf;
+  src_class->blit_to_framebuffer =
+    meta_screen_cast_monitor_stream_src_blit_to_framebuffer;
   src_class->set_cursor_metadata =
     meta_screen_cast_monitor_stream_src_set_cursor_metadata;
 }