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, 39 insertions, 21 deletions

diff --git a/source/blender/draw/intern/draw_manager_data.c b/source/blender/draw/intern/draw_manager_data.c
index b955bd3000c..fd4652a0305 100644
--- a/source/blender/draw/intern/draw_manager_data.c
+++ b/source/blender/draw/intern/draw_manager_data.c
@@ -335,6 +335,41 @@ void DRW_shgroup_call_object_add(DRWShadingGroup *shgroup, Gwn_Batch *geom, Obje
 	BLI_LINKS_APPEND(&shgroup->calls, call);
 }
 
+void DRW_shgroup_call_instances_add(DRWShadingGroup *shgroup, Gwn_Batch *geom, float (*obmat)[4], unsigned int *count)
+{
+	BLI_assert(geom != NULL);
+	BLI_assert(shgroup->type == DRW_SHG_NORMAL);
+
+	DRWCall *call = BLI_mempool_alloc(DST.vmempool->calls);
+	call->state = drw_call_state_create(shgroup, obmat, NULL);
+	call->type = DRW_CALL_INSTANCES;
+	call->instances.geometry = geom;
+	call->instances.count = count;
+#ifdef USE_GPU_SELECT
+	call->select_id = DST.select_id;
+#endif
+
+	BLI_LINKS_APPEND(&shgroup->calls, call);
+}
+
+/* These calls can be culled and are optimized for redraw */
+void DRW_shgroup_call_object_instances_add(DRWShadingGroup *shgroup, Gwn_Batch *geom, Object *ob, unsigned int *count)
+{
+	BLI_assert(geom != NULL);
+	BLI_assert(shgroup->type == DRW_SHG_NORMAL);
+
+	DRWCall *call = BLI_mempool_alloc(DST.vmempool->calls);
+	call->state = drw_call_state_object(shgroup, ob->obmat, ob);
+	call->type = DRW_CALL_INSTANCES;
+	call->instances.geometry = geom;
+	call->instances.count = count;
+#ifdef USE_GPU_SELECT
+	call->select_id = DST.select_id;
+#endif
+
+	BLI_LINKS_APPEND(&shgroup->calls, call);
+}
+
 void DRW_shgroup_call_generate_add(
         DRWShadingGroup *shgroup,
         DRWCallGenerateFn *geometry_fn, void *user_data,
@@ -466,18 +501,17 @@ static void drw_interface_instance_init(
 {
 	BLI_assert(shgroup->type == DRW_SHG_INSTANCE);
 	BLI_assert(batch != NULL);
+	BLI_assert(format != NULL);
 
 	drw_interface_init(shgroup, shader);
 
 	shgroup->instance_geom = batch;
 #ifndef NDEBUG
-	shgroup->attribs_count = (format != NULL) ? format->attrib_ct : 0;
+	shgroup->attribs_count = format->attrib_ct;
 #endif
 
-	if (format != NULL) {
-		DRW_instancing_buffer_request(DST.idatalist, format, batch, shgroup,
-		                              &shgroup->instance_geom, &shgroup->instance_vbo);
-	}
+	DRW_instancing_buffer_request(DST.idatalist, format, batch, shgroup,
+	                              &shgroup->instance_geom, &shgroup->instance_vbo);
 }
 
 static void drw_interface_batching_init(
@@ -741,22 +775,6 @@ void DRW_shgroup_instance_batch(DRWShadingGroup *shgroup, struct Gwn_Batch *batc
 #endif
 }
 
-/* Used for instancing with no attributes */
-void DRW_shgroup_set_instance_count(DRWShadingGroup *shgroup, unsigned int count)
-{
-	BLI_assert(shgroup->type == DRW_SHG_INSTANCE);
-	BLI_assert(shgroup->instance_count == 0);
-	BLI_assert(shgroup->attribs_count == 0);
-
-#ifdef USE_GPU_SELECT
-	if (G.f & G_PICKSEL) {
-		shgroup->override_selectid = DST.select_id;
-	}
-#endif
-
-	shgroup->instance_count = count;
-}
-
 unsigned int DRW_shgroup_get_instance_count(const DRWShadingGroup *shgroup)
 {
 	return shgroup->instance_count;