gl/dispmanx: surfaceless EGL context support

Show the DispmanX window only if there's no shared external GL context
set up. When a window is required by the context a transparent
DispmanX element is created and later on made visible by the ::show
method.

https://bugzilla.gnome.org/show_bug.cgi?id=746632

gst-libs/gst/gl/dispmanx/gstglwindow_dispmanx_egl.c

@@ -29,18 +29,31 @@
 
 #include "gstglwindow_dispmanx_egl.h"
 
+
+#ifndef ELEMENT_CHANGE_LAYER
+/* copied from interface/vmcs_host/vc_vchi_dispmanx.h of userland.git */
+#define ELEMENT_CHANGE_LAYER          (1<<0)
+#define ELEMENT_CHANGE_OPACITY        (1<<1)
+#define ELEMENT_CHANGE_DEST_RECT      (1<<2)
+#define ELEMENT_CHANGE_SRC_RECT       (1<<3)
+#define ELEMENT_CHANGE_MASK_RESOURCE  (1<<4)
+#define ELEMENT_CHANGE_TRANSFORM      (1<<5)
+#endif
+
 #define GST_CAT_DEFAULT gst_gl_window_debug
 
 #define gst_gl_window_dispmanx_egl_parent_class parent_class
 G_DEFINE_TYPE (GstGLWindowDispmanxEGL, gst_gl_window_dispmanx_egl,
     GST_GL_TYPE_WINDOW);
 
+static void gst_gl_window_dispmanx_egl_finalize (GObject * object);
 static guintptr gst_gl_window_dispmanx_egl_get_window_handle (GstGLWindow *
     window);
 static void gst_gl_window_dispmanx_egl_set_window_handle (GstGLWindow * window,
     guintptr handle);
 static void gst_gl_window_dispmanx_egl_set_preferred_size (GstGLWindow * window,
     gint width, gint height);
+static void gst_gl_window_dispmanx_egl_show (GstGLWindow * window);
 static void gst_gl_window_dispmanx_egl_draw (GstGLWindow * window);
 static void gst_gl_window_dispmanx_egl_run (GstGLWindow * window);
 static void gst_gl_window_dispmanx_egl_quit (GstGLWindow * window);
@@ -53,17 +66,19 @@ static guintptr gst_gl_window_dispmanx_egl_get_display (GstGLWindow * window);
 
 
 static void window_resize (GstGLWindowDispmanxEGL * window_egl, guint width,
-    guint height);
+    guint height, gboolean visible);
 
 static void
 gst_gl_window_dispmanx_egl_class_init (GstGLWindowDispmanxEGLClass * klass)
 {
   GstGLWindowClass *window_class = (GstGLWindowClass *) klass;
+  GObjectClass *gobject_class = (GObjectClass *) klass;
 
   window_class->get_window_handle =
       GST_DEBUG_FUNCPTR (gst_gl_window_dispmanx_egl_get_window_handle);
   window_class->set_window_handle =
       GST_DEBUG_FUNCPTR (gst_gl_window_dispmanx_egl_set_window_handle);
+  window_class->show = GST_DEBUG_FUNCPTR (gst_gl_window_dispmanx_egl_show);
   window_class->draw_unlocked =
       GST_DEBUG_FUNCPTR (gst_gl_window_dispmanx_egl_draw);
   window_class->draw = GST_DEBUG_FUNCPTR (gst_gl_window_dispmanx_egl_draw);
@@ -77,11 +92,26 @@ gst_gl_window_dispmanx_egl_class_init (GstGLWindowDispmanxEGLClass * klass)
       GST_DEBUG_FUNCPTR (gst_gl_window_dispmanx_egl_get_display);
   window_class->set_preferred_size =
       GST_DEBUG_FUNCPTR (gst_gl_window_dispmanx_egl_set_preferred_size);
+
+  gobject_class->finalize = gst_gl_window_dispmanx_egl_finalize;
 }
 
 static void
-gst_gl_window_dispmanx_egl_init (GstGLWindowDispmanxEGL * window)
+gst_gl_window_dispmanx_egl_init (GstGLWindowDispmanxEGL * window_egl)
 {
+  window_egl->main_context = g_main_context_new ();
+  window_egl->loop = g_main_loop_new (window_egl->main_context, FALSE);
+}
+
+static void
+gst_gl_window_dispmanx_egl_finalize (GObject * object)
+{
+  GstGLWindowDispmanxEGL *window_egl = GST_GL_WINDOW_DISPMANX_EGL (object);
+
+  g_main_loop_unref (window_egl->loop);
+  g_main_context_unref (window_egl->main_context);
+
+  G_OBJECT_CLASS (parent_class)->finalize (object);
 }
 
 /* Must be called in the gl thread */
@@ -96,6 +126,7 @@ gst_gl_window_dispmanx_egl_new (void)
 
   window->egldisplay = EGL_DEFAULT_DISPLAY;
 
+  window->visible = FALSE;
   window->display = 0;
   window->dp_width = 0;
   window->dp_height = 0;
@@ -140,16 +171,18 @@ gst_gl_window_dispmanx_egl_open (GstGLWindow * window, GError ** error)
   GST_DEBUG ("Got display size: %dx%d\n", window_egl->dp_width,
       window_egl->dp_height);
 
+  window_egl->native.element = 0;
+
+  return TRUE;
+}
+
+gboolean
+gst_gl_window_dispmanx_egl_create_window (GstGLWindowDispmanxEGL * window_egl)
+{
   window_egl->native.width = 0;
   window_egl->native.height = 0;
   window_egl->display = vc_dispmanx_display_open (0);
-  window_egl->native.element = 0;
+  window_resize (window_egl, 16, 16, FALSE);
-
-  window_egl->main_context = g_main_context_new ();
-  window_egl->loop = g_main_loop_new (window_egl->main_context, FALSE);
-
-  window_resize (window_egl, 16, 16);
-
   return TRUE;
 }
 
@@ -221,7 +254,11 @@ gst_gl_window_dispmanx_egl_send_message_async (GstGLWindow * window,
 static guintptr
 gst_gl_window_dispmanx_egl_get_window_handle (GstGLWindow * window)
 {
-  return (guintptr) & GST_GL_WINDOW_DISPMANX_EGL (window)->native;
+  GstGLWindowDispmanxEGL *window_egl;
+  window_egl = GST_GL_WINDOW_DISPMANX_EGL (window);
+  if (window_egl->native.element)
+    return (guintptr) & window_egl->native;
+  return 0;
 }
 
 static void
@@ -231,27 +268,32 @@ gst_gl_window_dispmanx_egl_set_window_handle (GstGLWindow * window,
 }
 
 static void
-gst_gl_window_dispmanx_egl_set_preferred_size (GstGLWindow * window, gint width, gint height)
+gst_gl_window_dispmanx_egl_set_preferred_size (GstGLWindow * window, gint width,
+    gint height)
 {
   GstGLWindowDispmanxEGL *window_egl = GST_GL_WINDOW_DISPMANX_EGL (window);
 
+  GST_DEBUG_OBJECT (window, "set preferred size to %dx%d", width, height);
   window_egl->preferred_width = width;
   window_egl->preferred_height = height;
 }
 
 static void
-window_resize (GstGLWindowDispmanxEGL * window_egl, guint width, guint height)
+window_resize (GstGLWindowDispmanxEGL * window_egl, guint width, guint height,
+    gboolean visible)
 {
-  GST_DEBUG ("resizing window from %ux%u to %ux%u",
+  GST_DEBUG ("resizing %s window from %ux%u to %ux%u",
-      window_egl->native.width, window_egl->native.height, width, height);
+      visible ? "visible" : "invisible", window_egl->native.width,
+      window_egl->native.height, width, height);
 
   if (window_egl->display) {
     VC_RECT_T dst_rect;
     VC_RECT_T src_rect;
     GstVideoRectangle src, dst, res;
     DISPMANX_UPDATE_HANDLE_T dispman_update;
+    uint32_t opacity = visible ? 255 : 0;
     VC_DISPMANX_ALPHA_T alpha =
-        { DISPMANX_FLAGS_ALPHA_FIXED_ALL_PIXELS, 255, 0 };
+        { DISPMANX_FLAGS_ALPHA_FIXED_ALL_PIXELS, opacity, 0 };
 
     /* Center width*height frame inside dp_width*dp_height */
     src.w = width;
@@ -275,9 +317,12 @@ window_resize (GstGLWindowDispmanxEGL * window_egl, guint width, guint height)
     dispman_update = vc_dispmanx_update_start (0);
 
     if (window_egl->native.element) {
+      uint32_t change_flags =
+          ELEMENT_CHANGE_OPACITY | ELEMENT_CHANGE_DEST_RECT |
+          ELEMENT_CHANGE_SRC_RECT;
       vc_dispmanx_element_change_attributes (dispman_update,
-          window_egl->native.element, 0x00000110, 0, 0, &dst_rect, &src_rect, 0,
+          window_egl->native.element, change_flags, 0, opacity, &dst_rect,
-          0);
+          &src_rect, 0, 0);
     } else {
       window_egl->native.element = vc_dispmanx_element_add (dispman_update,
           window_egl->display, 0, &dst_rect, 0, &src_rect,
@@ -295,6 +340,17 @@ window_resize (GstGLWindowDispmanxEGL * window_egl, guint width, guint height)
   window_egl->native.height = height;
 }
 
+static void
+gst_gl_window_dispmanx_egl_show (GstGLWindow * window)
+{
+  GstGLWindowDispmanxEGL *window_egl = GST_GL_WINDOW_DISPMANX_EGL (window);
+
+  if (!window_egl->visible) {
+    window_resize (window_egl, window_egl->preferred_width, window_egl->preferred_height, TRUE);
+    window_egl->visible = TRUE;
+  }
+}
+
 static void
 draw_cb (gpointer data)
 {
@@ -303,13 +359,6 @@ draw_cb (gpointer data)
   GstGLContext *context = gst_gl_window_get_context (window);
   GstGLContextClass *context_class = GST_GL_CONTEXT_GET_CLASS (context);
 
-  if (window_egl->native.width != window_egl->preferred_width
-      || window_egl->native.height != window_egl->preferred_height) {
-    GST_DEBUG ("dimensions don't match, attempting resize");
-    window_resize (window_egl, window_egl->preferred_width,
-        window_egl->preferred_height);
-  }
-
   if (window->draw)
     window->draw (window->draw_data);
 

gst-libs/gst/gl/dispmanx/gstglwindow_dispmanx_egl.h

@@ -54,6 +54,8 @@ struct _GstGLWindowDispmanxEGL {
   GMainContext *main_context;
   GMainLoop *loop;
 
+  gboolean visible;
+
   gpointer _reserved[GST_PADDING];
 };
 
@@ -68,6 +70,7 @@ struct _GstGLWindowDispmanxEGLClass {
 GType gst_gl_window_dispmanx_egl_get_type     (void);
 
 GstGLWindowDispmanxEGL * gst_gl_window_dispmanx_egl_new  (void);
+gboolean gst_gl_window_dispmanx_egl_create_window (GstGLWindowDispmanxEGL * window_egl);
 
 G_END_DECLS
 

gst-libs/gst/gl/egl/gstglcontext_egl.c

@@ -37,6 +37,9 @@
 #if GST_GL_HAVE_WINDOW_WIN32
 #include "../win32/gstglwindow_win32.h"
 #endif
+#if GST_GL_HAVE_WINDOW_DISPMANX
+#include "../dispmanx/gstglwindow_dispmanx_egl.h"
+#endif
 
 #define GST_CAT_DEFAULT gst_gl_context_debug
 
@@ -391,6 +394,12 @@ gst_gl_context_egl_create_context (GstGLContext * context,
     if (GST_GL_IS_WINDOW_WIN32 (context->window)) {
       gst_gl_window_win32_create_window ((GstGLWindowWin32 *) context->window);
     }
+#endif
+#if GST_GL_HAVE_WINDOW_DISPMANX
+    if (GST_GL_IS_WINDOW_DISPMANX_EGL (context->window)) {
+      gst_gl_window_dispmanx_egl_create_window ((GstGLWindowDispmanxEGL *)
+          context->window);
+    }
 #endif
   }