Draw Cache: avoid recalculating 'poly_normals'

Call `BKE_mesh_ensure_normals_for_display` to avoid recalculating
poly_normals.

**Benchmark**
||master:|PATCH:
|---|---|---|
|looptris_test:|Average: 3.995076 FPS|Average: 4.047470 FPS
||rdata 11ms iter 91ms (frame 235ms)|rdata 11ms iter 86ms (frame 233ms)
|subdiv_mesh_cage_and_final:|Average: 1.884492 FPS|Average: 1.900114 FPS
||rdata 7ms iter 42ms (frame 268ms)|rdata 7ms iter 39ms (frame 265ms)
||rdata 7ms iter 44ms (frame 259ms)|rdata 7ms iter 42ms (frame 257ms)
|subdiv_mesh_final_only:|Average: 6.245944 FPS|Average: 6.289000 FPS
||rdata 3ms iter 23ms (frame 153ms)|rdata 3ms iter 21ms (frame 154ms)
|subdiv_mesh_final_only_ledge:|Average: 6.263482 FPS|Average: 6.187218 FPS
||rdata 3ms iter 23ms (frame 156ms)|rdata 3ms iter 22ms (frame 154ms)

Reviewed By: jbakker

Differential Revision: https://developer.blender.org/D11527

1 files changed, 2 insertions, 11 deletions

diff --git a/source/blender/draw/intern/draw_cache_extract_mesh_render_data.c b/source/blender/draw/intern/draw_cache_extract_mesh_render_data.c
index 7e9fe9b3bdb..494217ee908 100644
--- a/source/blender/draw/intern/draw_cache_extract_mesh_render_data.c
+++ b/source/blender/draw/intern/draw_cache_extract_mesh_render_data.c
@@ -308,16 +308,8 @@ void mesh_render_data_update_normals(MeshRenderData *mr, const eMRDataType data_
   if (mr->extract_type != MR_EXTRACT_BMESH) {
     /* Mesh */
     if (data_flag & (MR_DATA_POLY_NOR | MR_DATA_LOOP_NOR | MR_DATA_TAN_LOOP_NOR)) {
-      mr->poly_normals = MEM_mallocN(sizeof(*mr->poly_normals) * mr->poly_len, __func__);
-      BKE_mesh_calc_normals_poly((MVert *)mr->mvert,
-                                 NULL,
-                                 mr->vert_len,
-                                 mr->mloop,
-                                 mr->mpoly,
-                                 mr->loop_len,
-                                 mr->poly_len,
-                                 mr->poly_normals,
-                                 true);
+      BKE_mesh_ensure_normals_for_display(mr->me);
+      mr->poly_normals = CustomData_get_layer(&mr->me->pdata, CD_NORMAL);
     }
     if (((data_flag & MR_DATA_LOOP_NOR) && is_auto_smooth) || (data_flag & MR_DATA_TAN_LOOP_NOR)) {
       mr->loop_normals = MEM_mallocN(sizeof(*mr->loop_normals) * mr->loop_len, __func__);
@@ -507,7 +499,6 @@ MeshRenderData *mesh_render_data_create(Mesh *me,
 void mesh_render_data_free(MeshRenderData *mr)
 {
   MEM_SAFE_FREE(mr->mlooptri);
-  MEM_SAFE_FREE(mr->poly_normals);
   MEM_SAFE_FREE(mr->loop_normals);
 
   /* Loose geometry are owned by MeshBufferExtractionCache. */