framebuffer: Adds a context getter for CoglFramebuffer

This adds a function to query what CoglContext a given framebuffer
belongs too. This can be useful if you pass framebuffer pointers around
and at some point you want to create another framebuffer as part of the
same context as a given framebuffer without assuming there is a single
default context.

Reviewed-by: Neil Roberts <neil@linux.intel.com>

cogl/cogl-framebuffer.c

@@ -1549,6 +1549,14 @@ cogl_framebuffer_set_dither_enabled (CoglFramebuffer *framebuffer,
   framebuffer->dither_enabled = dither_enabled;
 }
 
+CoglContext *
+cogl_framebuffer_get_context (CoglFramebuffer *framebuffer)
+{
+  g_return_val_if_fail (framebuffer != NULL, NULL);
+
+  return framebuffer->context;
+}
+
 gboolean
 _cogl_framebuffer_try_fast_read_pixel (CoglFramebuffer *framebuffer,
                                        int x,

cogl/cogl-framebuffer.h

@@ -261,6 +261,22 @@ void
 cogl_framebuffer_set_color_mask (CoglFramebuffer *framebuffer,
                                  CoglColorMask color_mask);
 
+#define cogl_framebuffer_get_context cogl_framebuffer_get_context_EXP
+/**
+ * @framebuffer: A #CoglFramebuffer
+ *
+ * Can be used to query the #CoglContext a given @framebuffer was
+ * instantiated within. This is the #CoglContext that was passed to
+ * cogl_onscreen_new() for example.
+ *
+ * Return value: The #CoglContext that the given @framebuffer was
+ *               instantiated within.
+ * Since: 1.8
+ * Stability: unstable
+ */
+CoglContext *
+cogl_framebuffer_get_context (CoglFramebuffer *framebuffer);
+
 #define cogl_framebuffer_swap_buffers cogl_framebuffer_swap_buffers_EXP
 void
 cogl_framebuffer_swap_buffers (CoglFramebuffer *framebuffer);

doc/reference/cogl-2.0-experimental/cogl-2.0-experimental-sections.txt

@@ -322,6 +322,7 @@ cogl_framebuffer_get_blue_bits
 cogl_framebuffer_get_blue_bits
 cogl_framebuffer_get_color_mask
 cogl_framebuffer_set_color_mask
+cogl_framebuffer_get_context
 cogl_framebuffer_swap_buffers
 cogl_framebuffer_swap_region
 cogl_framebuffer_add_swap_buffers_callback