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, 20 insertions, 17 deletions

diff --git a/source/blender/draw/intern/draw_manager_exec.c b/source/blender/draw/intern/draw_manager_exec.c
index 0cdf5d78a43..055baff6a96 100644
--- a/source/blender/draw/intern/draw_manager_exec.c
+++ b/source/blender/draw/intern/draw_manager_exec.c
@@ -618,7 +618,7 @@ static void draw_geometry_prepare(DRWShadingGroup *shgroup, DRWCallState *state)
 }
 
 static void draw_geometry_execute_ex(
-        DRWShadingGroup *shgroup, Gwn_Batch *geom, unsigned int start, unsigned int count)
+        DRWShadingGroup *shgroup, Gwn_Batch *geom, unsigned int start, unsigned int count, bool draw_instance)
 {
 	/* Special case: empty drawcall, placement is done via shader, don't bind anything. */
 	if (geom == NULL) {
@@ -632,18 +632,15 @@ static void draw_geometry_execute_ex(
 	GWN_batch_program_set_no_use(geom, GPU_shader_get_program(shgroup->shader), GPU_shader_get_interface(shgroup->shader));
 	/* XXX hacking gawain. we don't want to call glUseProgram! (huge performance loss) */
 	geom->program_in_use = true;
-	if (ELEM(shgroup->type, DRW_SHG_INSTANCE, DRW_SHG_INSTANCE_EXTERNAL)) {
-		GWN_batch_draw_range_ex(geom, start, count, true);
-	}
-	else {
-		GWN_batch_draw_range(geom, start, count);
-	}
+
+	GWN_batch_draw_range_ex(geom, start, count, draw_instance);
+
 	geom->program_in_use = false; /* XXX hacking gawain */
 }
 
 static void draw_geometry_execute(DRWShadingGroup *shgroup, Gwn_Batch *geom)
 {
-	draw_geometry_execute_ex(shgroup, geom, 0, 0);
+	draw_geometry_execute_ex(shgroup, geom, 0, 0, false);
 }
 
 static void bind_texture(GPUTexture *tex)
@@ -817,7 +814,7 @@ static void draw_shgroup(DRWShadingGroup *shgroup, DRWState pass_state)
 				if (shgroup->instance_geom != NULL) {
 					GPU_SELECT_LOAD_IF_PICKSEL(shgroup->override_selectid);
 					draw_geometry_prepare(shgroup, NULL);
-					draw_geometry_execute(shgroup, shgroup->instance_geom);
+					draw_geometry_execute_ex(shgroup, shgroup->instance_geom, 0, 0, true);
 				}
 			}
 			else {
@@ -826,7 +823,7 @@ static void draw_shgroup(DRWShadingGroup *shgroup, DRWState pass_state)
 					draw_geometry_prepare(shgroup, NULL);
 					GPU_SELECT_LOAD_IF_PICKSEL_LIST(shgroup, start, count)
 					{
-						draw_geometry_execute_ex(shgroup, shgroup->instance_geom, start, count);
+						draw_geometry_execute_ex(shgroup, shgroup->instance_geom, start, count, true);
 					}
 					GPU_SELECT_LOAD_IF_PICKSEL_LIST_END(start, count)
 				}
@@ -839,7 +836,7 @@ static void draw_shgroup(DRWShadingGroup *shgroup, DRWState pass_state)
 				draw_geometry_prepare(shgroup, NULL);
 				GPU_SELECT_LOAD_IF_PICKSEL_LIST(shgroup, start, count)
 				{
-					draw_geometry_execute_ex(shgroup, shgroup->batch_geom, start, count);
+					draw_geometry_execute_ex(shgroup, shgroup->batch_geom, start, count, false);
 				}
 				GPU_SELECT_LOAD_IF_PICKSEL_LIST_END(start, count)
 			}
@@ -865,12 +862,18 @@ static void draw_shgroup(DRWShadingGroup *shgroup, DRWState pass_state)
 			GPU_SELECT_LOAD_IF_PICKSEL_CALL(call);
 			draw_geometry_prepare(shgroup, call->state);
 
-			if (call->type == DRW_CALL_SINGLE) {
-				draw_geometry_execute(shgroup, call->single.geometry);
-			}
-			else {
-				BLI_assert(call->type == DRW_CALL_GENERATE);
-				call->generate.geometry_fn(shgroup, draw_geometry_execute, call->generate.user_data);
+			switch (call->type) {
+				case DRW_CALL_SINGLE:
+					draw_geometry_execute(shgroup, call->single.geometry);
+					break;
+				case DRW_CALL_INSTANCES:
+					draw_geometry_execute_ex(shgroup, call->instances.geometry, 0, *call->instances.count, true);
+					break;
+				case DRW_CALL_GENERATE:
+					call->generate.geometry_fn(shgroup, draw_geometry_execute, call->generate.user_data);
+					break;
+				default:
+					BLI_assert(0);
 			}
 		}
 		/* Reset state */