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diff --git a/source/blender/gpu/intern/gpu_index_buffer_private.hh b/source/blender/gpu/intern/gpu_index_buffer_private.hh
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+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2020 Blender Foundation.
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup gpu
+ */
+
+#pragma once
+
+#include "BLI_assert.h"
+
+#include "GPU_index_buffer.h"
+
+#define GPU_TRACK_INDEX_RANGE 1
+
+namespace blender::gpu {
+
+typedef enum {
+  GPU_INDEX_U16,
+  GPU_INDEX_U32,
+} GPUIndexBufType;
+
+static inline size_t to_bytesize(GPUIndexBufType type)
+{
+  return (type == GPU_INDEX_U32) ? sizeof(uint32_t) : sizeof(uint16_t);
+}
+
+/**
+ * Base class which is then specialized for each implementation (GL, VK, ...).
+ *
+ * NOTE: IndexBuf does not hold any GPUPrimType. This is because it can be interpreted
+ *       differently by multiple batches.
+ **/
+class IndexBuf {
+ protected:
+  /** Type of indices used inside this buffer. */
+  GPUIndexBufType index_type_ = GPU_INDEX_U32;
+  /** Offset in this buffer to the first index to render. Is 0 if not a subrange.  */
+  uint32_t index_start_ = 0;
+  /** Number of indices to render. */
+  uint32_t index_len_ = 0;
+  /** Base index: Added to all indices after fetching. Allows index compression. */
+  uint32_t index_base_ = 0;
+  /** Bookeeping. */
+  bool is_init_ = false;
+  /** Is this object only a reference to a subrange of another IndexBuf. */
+  bool is_subrange_ = false;
+
+  union {
+    /** Mapped buffer data. non-NULL indicates not yet sent to VRAM. */
+    void *data_ = nullptr;
+    /** If is_subrange is true, this is the source index buffer. */
+    IndexBuf *src_;
+  };
+
+ public:
+  IndexBuf(){};
+  virtual ~IndexBuf();
+
+  void init(uint indices_len, uint32_t *indices);
+  void init_subrange(IndexBuf *elem_src, uint start, uint length);
+
+  uint32_t index_len_get(void) const
+  {
+    return index_len_;
+  }
+  /* Return size in byte of the drawable data buffer range. Actual buffer size might be bigger. */
+  size_t size_get(void)
+  {
+    return index_len_ * to_bytesize(index_type_);
+  };
+
+  bool is_init(void) const
+  {
+    return is_init_;
+  };
+
+ private:
+  inline void squeeze_indices_short(uint min_idx, uint max_idx);
+  inline uint index_range(uint *r_min, uint *r_max);
+};
+
+/* Syntacting suggar. */
+static inline GPUIndexBuf *wrap(IndexBuf *indexbuf)
+{
+  return reinterpret_cast<GPUIndexBuf *>(indexbuf);
+}
+static inline IndexBuf *unwrap(GPUIndexBuf *indexbuf)
+{
+  return reinterpret_cast<IndexBuf *>(indexbuf);
+}
+
+static inline int indices_per_primitive(GPUPrimType prim_type)
+{
+  switch (prim_type) {
+    case GPU_PRIM_POINTS:
+      return 1;
+    case GPU_PRIM_LINES:
+      return 2;
+    case GPU_PRIM_TRIS:
+      return 3;
+    case GPU_PRIM_LINES_ADJ:
+      return 4;
+    default:
+      return -1;
+  }
+}
+
+}  // namespace blender::gpu