Add cogl_primitive_copy()

This adds a public function to make a copy of a primitive. The copy is
shallow which means it will share the same attributes and attribute
buffers. This could be useful for code that wants to have multiple
similar primitives with slightly modified properties.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

cogl/cogl-primitive.c

@@ -524,6 +524,22 @@ cogl_primitive_set_indices (CoglPrimitive *primitive,
   primitive->n_vertices = n_indices;
 }
 
+CoglPrimitive *
+cogl_primitive_copy (CoglPrimitive *primitive)
+{
+  CoglPrimitive *copy;
+
+  copy = cogl_primitive_new_with_attributes (primitive->mode,
+                                             primitive->n_vertices,
+                                             primitive->attributes,
+                                             primitive->n_attributes);
+
+  cogl_primitive_set_indices (copy, primitive->indices, primitive->n_vertices);
+  cogl_primitive_set_first_vertex (copy, primitive->first_vertex);
+
+  return copy;
+}
+
 CoglPrimitive *
 _cogl_primitive_immutable_ref (CoglPrimitive *primitive)
 {

cogl/cogl-primitive.h

@@ -774,6 +774,21 @@ cogl_primitive_set_indices (CoglPrimitive *primitive,
                             CoglIndices *indices,
                             int n_indices);
 
+/**
+ * cogl_primitive_copy:
+ * @primitive: A primitive copy
+ *
+ * Makes a copy of an existing #CoglPrimitive. Note that the primitive
+ * is a shallow copy which means it will use the same attributes and
+ * attribute buffers as the original primitive.
+ *
+ * Return value: the new primitive
+ * Since: 1.10
+ * Stability: unstable
+ */
+CoglPrimitive *
+cogl_primitive_copy (CoglPrimitive *primitive);
+
 /**
  * cogl_primitive_draw:
  * @primitive: A #CoglPrimitive object

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

@@ -237,6 +237,7 @@ cogl_primitive_set_mode
 cogl_primitive_set_attributes
 cogl_primitive_set_indices
 cogl_primitive_draw
+cogl_primitive_copy
 </SECTION>
 
 <SECTION>