API: Add gdk_display_create_gl_context()

This is an alternative to gdk_surface_create_gl_context() when the
context is meant to only draw to textures.

This is useful in the testsuite or in GStreamer or with GLArea,
basically whenever we want to do GL stuff but don't need to actually
draw anything on screen.

A bunch of code will need to be updated to deal with context->surface
being NULL.

diff --git a/gdk/gdkdisplay.c b/gdk/gdkdisplay.c
index 075342a26bc969dc0b3424de9456543b86723812..d5defbeb82fdb1767efda74498d100d005340649 100644 (file)
--- a/gdk/gdkdisplay.c
+++ b/gdk/gdkdisplay.c
@@ -1325,6 +1325,38 @@ gdk_display_prepare_gl (GdkDisplay  *self,
     }
 }
 
+/**
+ * gdk_display_create_gl_context:
+ * @self: a `GdkDisplay`
+ * @error: return location for an error
+ *
+ * Creates a new `GdkGLContext` for the `GdkDisplay`.
+ *
+ * The context is disconnected from any particular surface or surface
+ * and cannot be used to draw to any surface. It can only be used to
+ * draw to non-surface framebuffers like textures.
+ *
+ * If the creation of the `GdkGLContext` failed, @error will be set.
+ * Before using the returned `GdkGLContext`, you will need to
+ * call [method@Gdk.GLContext.make_current] or [method@Gdk.GLContext.realize].
+ *
+ * Returns: (transfer full) (nullable): the newly created `GdkGLContext`
+ *
+ * Since: 4.6
+ */
+GdkGLContext *
+gdk_display_create_gl_context (GdkDisplay  *self,
+                               GError     **error)
+{
+  g_return_val_if_fail (GDK_IS_DISPLAY (self), NULL);
+  g_return_val_if_fail (error == NULL || *error == NULL, NULL);
+
+  if (!gdk_display_prepare_gl (self, error))
+    return NULL;
+
+  return gdk_gl_context_new (self, NULL);
+}
+
 /*< private >
  * gdk_display_get_gl_context:
  * @self: the `GdkDisplay`

diff --git a/gdk/gdkdisplay.h b/gdk/gdkdisplay.h
index 9fabac6b50168fde29fccfab37fa01093e697a3e..52aa502247af01fe1139bdbe250247560ed736f2 100644 (file)
--- a/gdk/gdkdisplay.h
+++ b/gdk/gdkdisplay.h
@@ -71,6 +71,9 @@ gboolean    gdk_display_supports_input_shapes (GdkDisplay    *display);
 GDK_AVAILABLE_IN_4_4
 gboolean    gdk_display_prepare_gl         (GdkDisplay  *self,
                                             GError     **error);
+GDK_AVAILABLE_IN_4_6
+GdkGLContext *gdk_display_create_gl_context(GdkDisplay  *self,
+                                            GError     **error);
 
 GDK_AVAILABLE_IN_ALL
 GdkDisplay *gdk_display_get_default (void);

diff --git a/gdk/gdkglcontext.c b/gdk/gdkglcontext.c
index 812a3cd9d898e3bc8ef311befc4cc49e13463af2..422e0a189e2055956b8a25814acfab2ecd3a404c 100644 (file)
--- a/gdk/gdkglcontext.c
+++ b/gdk/gdkglcontext.c
@@ -722,15 +722,19 @@ gdk_gl_context_init (GdkGLContext *self)
 
 /* Must have called gdk_display_prepare_gl() before */
 GdkGLContext *
-gdk_gl_context_new_for_surface (GdkSurface *surface)
+gdk_gl_context_new (GdkDisplay *display,
+                    GdkSurface *surface)
 {
-  GdkDisplay *display = gdk_surface_get_display (surface);
-  GdkGLContext *shared = gdk_display_get_gl_context (display);
+  GdkGLContext *shared;
+
+  g_assert (surface == NULL || display == gdk_surface_get_display (surface));
 
   /* assert gdk_display_prepare_gl() had been called */
+  shared = gdk_display_get_gl_context (display);
   g_assert (shared);
 
   return g_object_new (G_OBJECT_TYPE (shared),
+                       "display", display,
                        "surface", surface,
                        NULL);
 }

diff --git a/gdk/gdkglcontextprivate.h b/gdk/gdkglcontextprivate.h
index 56fe04f903e4f8c9ec7fd75743e7c0322042646b..e07420f1c11706870727f291d338534892849cb6 100644 (file)
--- a/gdk/gdkglcontextprivate.h
+++ b/gdk/gdkglcontextprivate.h
@@ -99,7 +99,8 @@ gboolean                gdk_gl_backend_can_be_used              (GdkGLBackend
                                                                  GError         **error);
 void                    gdk_gl_backend_use                      (GdkGLBackend     backend_type);
 
-GdkGLContext *          gdk_gl_context_new_for_surface          (GdkSurface      *surface);
+GdkGLContext *          gdk_gl_context_new                      (GdkDisplay      *display,
+                                                                 GdkSurface      *surface);
 
 gboolean                gdk_gl_context_is_api_allowed           (GdkGLContext    *self,
                                                                  GdkGLAPI         api,

diff --git a/gdk/gdksurface.c b/gdk/gdksurface.c
index 9430a4a1116e98d2743a98695f333c679f0c8cbf..5b0c947ed3ad9380ea3ab4c8e6b9c58dc8bad779 100644 (file)
--- a/gdk/gdksurface.c
+++ b/gdk/gdksurface.c
@@ -1183,7 +1183,7 @@ gdk_surface_create_gl_context (GdkSurface   *surface,
   if (!gdk_display_prepare_gl (surface->display, error))
     return NULL;
 
-  return gdk_gl_context_new_for_surface (surface);
+  return gdk_gl_context_new (surface->display, surface);
 }
 
 /**