DRW: Refactor simple instancing.

Instead of creating a new instancing shading group without attrib, we now have instancing calls. The benefits is that they can be culled.
They can be used in conjuction with the standard and generate calls but shader must support it (which is generally not the case).
We store a pointer to the actual count so that the number can be tweaked between redraw.

This will makes multi layer rendering more efficient.

1 files changed, 6 insertions, 0 deletions

diff --git a/source/blender/draw/intern/draw_manager.h b/source/blender/draw/intern/draw_manager.h
index a037915fff1..58973471c4e 100644
--- a/source/blender/draw/intern/draw_manager.h
+++ b/source/blender/draw/intern/draw_manager.h
@@ -128,6 +128,7 @@ typedef struct DRWCallState {
 
 typedef enum {
 	DRW_CALL_SINGLE,                 /* A single batch */
+	DRW_CALL_INSTANCES,              /* Draw instances without any instancing attribs. */
 	DRW_CALL_GENERATE,               /* Uses a callback to draw with any number of batches. */
 } DRWCallType;
 
@@ -139,6 +140,11 @@ typedef struct DRWCall {
 		struct { /* type == DRW_CALL_SINGLE */
 			Gwn_Batch *geometry;
 		} single;
+		struct { /* type == DRW_CALL_INSTANCES */
+			Gwn_Batch *geometry;
+			/* Count can be adjusted between redraw. If needed, we can add fixed count. */
+			unsigned int *count;
+		} instances;
 		struct { /* type == DRW_CALL_GENERATE */
 			DRWCallGenerateFn *geometry_fn;
 			void *user_data;