[vbo indices] tweak add_indices api to return an id and add delete_indices api

Originally cogl_vertex_buffer_add_indices let the user pass in their own unique
ID for the indices; now the Id is generated internally and returned to the
caller.

cogl-vertex-buffer.h

@@ -305,8 +305,6 @@ typedef enum _CoglIndicesType
 /**
  * cogl_vertex_buffer_add_indices:
  * @handle: A vertex buffer handle
- * @id: Any unique number. It's used to identify the indices when you later
- *      call cogl_vertex_buffer_draw_elements()
  * @min_index: Specifies the minimum vertex index contained in indices
  * @max_index: Specifies the maximum vertex index contained in indices
  * @indices_type: a #CoglIndicesType specifying the data type used for
@@ -319,20 +317,36 @@ typedef enum _CoglIndicesType
  * array allows you to reference vertices multiple times, for example
  * during triangle strips.
  *
- * You should aim to use the COGL_INDICES_TYPE_UNSIGNED_SHORT when possible
- * and correctly reflect the range of index values in the {min,max}_index
- * arguments. This allows Cogl to optimize the internal storage used for
- * the indices and reduce the demand for memory bandwidth.
+ * You should aim to use the smallest data type possible and correctly reflect
+ * the range of index values in the {min,max}_index arguments. This allows Cogl
+ * to optimize the internal storage used for the indices and reduce the demand
+ * for memory bandwidth.
+ *
+ * Returns: An identifier (greater than 0) for the indices which you can
+ *          pass to cogl_vertex_buffer_draw_elements().
  */
-void
+int
 cogl_vertex_buffer_add_indices (CoglHandle       handle,
-                                int              id,
 			        int              min_index,
                                 int              max_index,
                                 CoglIndicesType  indices_type,
                                 const void      *indices_array,
                                 int              indices_len);
 
+/**
+ * cogl_vertex_buffer_delete_indices:
+ * @handle: A vertex buffer handle
+ * @indices_id: The identifier for a an array of indices previously added to
+ *              the given Cogl vertex buffer using
+ *              cogl_vertex_buffer_add_indices().
+ *
+ * Frees the resources associated with a previously added array of vertex
+ * indices.
+ */
+void
+cogl_vertex_buffer_delete_indices (CoglHandle handle,
+                                   int indices_id);
+
 /**
  * cogl_vertex_buffer_draw_elements:
  * @handle: A vertex buffer handle

common/cogl-vertex-buffer.c

@@ -1771,9 +1771,8 @@ get_indices_type_size (GLuint indices_type)
     }
 }
 
-void
+int
 cogl_vertex_buffer_add_indices (CoglHandle       handle,
-                                int              id,
 			        int              min_index,
                                 int              max_index,
                                 CoglIndicesType  indices_type,
@@ -1781,32 +1780,23 @@ cogl_vertex_buffer_add_indices (CoglHandle       handle,
                                 int              indices_len)
 {
   CoglVertexBuffer *buffer;
-  GList *l;
   gboolean fallback =
     (cogl_get_features () & COGL_FEATURE_VBOS) ? FALSE : TRUE;
   size_t indices_bytes;
   CoglVertexBufferIndices *indices;
 
-  _COGL_GET_CONTEXT (ctx, NO_RETVAL);
+  static int next_indices_id = 1;
+
+
+  _COGL_GET_CONTEXT (ctx, 0);
 
   if (!cogl_is_vertex_buffer (handle))
-    return;
+    return 0;
 
   buffer = _cogl_vertex_buffer_pointer_from_handle (handle);
 
-  for (l = buffer->indices; l; l = l->next)
-    {
-      CoglVertexBufferIndices *current_indices = l->data;
-      if (current_indices->id == id)
-        {
-          free_vertex_buffer_indices (l->data);
-          buffer->indices = g_list_delete_link (buffer->indices, l);
-          break;
-        }
-    }
-
   indices = g_slice_alloc (sizeof (CoglVertexBufferIndices));
-  indices->id = id;
+  indices->id = next_indices_id;
   indices->min_index = min_index;
   indices->max_index = max_index;
 
@@ -1818,7 +1808,7 @@ cogl_vertex_buffer_add_indices (CoglHandle       handle,
     {
       g_critical ("unknown indices type %d", indices_type);
       g_slice_free (CoglVertexBufferIndices, indices);
-      return;
+      return 0;
     }
 
   indices_bytes = get_indices_type_size (indices->type) * indices_len;
@@ -1840,6 +1830,32 @@ cogl_vertex_buffer_add_indices (CoglHandle       handle,
     }
 
   buffer->indices = g_list_prepend (buffer->indices, indices);
+
+  return next_indices_id++;
+}
+
+void
+cogl_vertex_buffer_delete_indices (CoglHandle handle,
+                                   int indices_id)
+{
+  CoglVertexBuffer *buffer;
+  GList *l;
+
+  if (!cogl_is_vertex_buffer (handle))
+    return;
+
+  buffer = _cogl_vertex_buffer_pointer_from_handle (handle);
+
+  for (l = buffer->indices; l; l = l->next)
+    {
+      CoglVertexBufferIndices *current_indices = l->data;
+      if (current_indices->id == indices_id)
+        {
+          free_vertex_buffer_indices (l->data);
+          buffer->indices = g_list_delete_link (buffer->indices, l);
+          return;
+        }
+    }
 }
 
 void

doc/reference/cogl/cogl-sections.txt

@@ -309,6 +309,7 @@ cogl_vertex_buffer_enable
 cogl_vertex_buffer_draw
 CoglIndicesType
 cogl_vertex_buffer_add_indices
+cogl_vertex_buffer_delete_indices
 cogl_vertex_buffer_draw_elements
 <SUBSECTION Private>
 CoglVertexBufferAttribFlags