DRW: Add instance buffer manager.

This manager allows to distribute existing batches for instancing
attributes. This reduce the number of batches creation.
Querying a batch is done with a vertex format. This format should
be static so that it's pointer never changes (because we are using
this pointer as identifier [we don't want to check the full format
that would be too slow]).

This might make the original Instance Data manager useless but it's currently used by DRW_object_engine_data_ensure().

1 files changed, 14 insertions, 0 deletions

diff --git a/source/blender/draw/intern/draw_instance_data.h b/source/blender/draw/intern/draw_instance_data.h
index c8376189396..a7a66c9baff 100644
--- a/source/blender/draw/intern/draw_instance_data.h
+++ b/source/blender/draw/intern/draw_instance_data.h
@@ -26,16 +26,30 @@
 #ifndef __DRAW_INSTANCE_DATA_H__
 #define __DRAW_INSTANCE_DATA_H__
 
+#include "BLI_compiler_attrs.h"
+#include "BLI_sys_types.h"
+
+#include "GPU_batch.h"
+
 #define MAX_INSTANCE_DATA_SIZE 42 /* Can be adjusted for more */
 
 typedef struct DRWInstanceData DRWInstanceData;
 typedef struct DRWInstanceDataList DRWInstanceDataList;
 
+struct DRWShadingGroup;
+
 void *DRW_instance_data_next(DRWInstanceData *idata);
 void *DRW_instance_data_get(DRWInstanceData *idata);
 DRWInstanceData *DRW_instance_data_request(
         DRWInstanceDataList *idatalist, unsigned int attrib_size, unsigned int instance_group);
 
+void DRW_instance_buffer_request(
+        DRWInstanceDataList *idatalist, Gwn_VertFormat *format, struct DRWShadingGroup *shgroup,
+        Gwn_Batch **r_batch, Gwn_VertBuf **r_vert, Gwn_PrimType type);
+
+/* Upload all instance data to the GPU as soon as possible. */
+void DRW_instance_buffer_finish(DRWInstanceDataList *idatalist);
+
 void DRW_instance_data_list_reset(DRWInstanceDataList *idatalist);
 void DRW_instance_data_list_free_unused(DRWInstanceDataList *idatalist);
 void DRW_instance_data_list_resize(DRWInstanceDataList *idatalist);