1 files changed, 14 insertions, 0 deletions
diff --git a/source/blender/gpu/GPU_index_buffer.h b/source/blender/gpu/GPU_index_buffer.h
index 4e8d854c7ce..03d60c60b4b 100644
--- a/source/blender/gpu/GPU_index_buffer.h
+++ b/source/blender/gpu/GPU_index_buffer.h
@@ -44,6 +44,7 @@ typedef struct GPUIndexBufBuilder {
   uint index_max;
   GPUPrimType prim_type;
   uint32_t *data;
+  const struct GPUIndexBufBuilder *parent;
 } GPUIndexBufBuilder;
 
 /* supports all primitive types. */
@@ -53,6 +54,19 @@ void GPU_indexbuf_init_ex(GPUIndexBufBuilder *, GPUPrimType, uint index_len, uin
 void GPU_indexbuf_init(GPUIndexBufBuilder *, GPUPrimType, uint prim_len, uint vertex_len);
 GPUIndexBuf *GPU_indexbuf_build_on_device(uint index_len);
 
+/*
+ * Thread safe sub builders.
+ *
+ * Note that `GPU_indexbuf_subbuilder_init` and `GPU_indexbuf_subbuilder_finish` are not thread
+ * safe and should be called when no threads are active. The pattern is to create a subbuilder for
+ * each thread/task. Each thread/task would update their sub builder. When all thread are completed
+ * the sub-builders can then be merged back to the parent builder.
+ */
+void GPU_indexbuf_subbuilder_init(const GPUIndexBufBuilder *parent_builder,
+                                  GPUIndexBufBuilder *sub_builder);
+void GPU_indexbuf_subbuilder_finish(GPUIndexBufBuilder *builder,
+                                    const GPUIndexBufBuilder *parent_builder);
+
 void GPU_indexbuf_add_generic_vert(GPUIndexBufBuilder *, uint v);
 void GPU_indexbuf_add_primitive_restart(GPUIndexBufBuilder *);