T88352: Use threaded ibo.tris extraction for single material meshes.

This patch adds a specific extraction method when the mesh has only
one material. This method is multi-threaded.

There is a trade-off in this patch as the ibo isn't compressed (it adds
restart indexes for hidden faces). So it depends if threading is faster
than the additional GPU buffer upload.

# Subdivided cube
I used a cube subdivided 7 times, modifiers applied. that gives around 400000 faces.

The test is selecting some vertices and move them. During this test the next buffers are updated on each frame:
* vbo.pos_nor
* vbo.lnor
* vbo.edit_data
* ibo.tris
* ibo.points

System info:
|platform| Linux-5.11.0-7614-generic-x86_64-with-glibc2.33|
| renderer|      AMD SIENNA_CICHLID (DRM 3.40.0, 5.11.0-7614-generic, LLVM 11.0.1)|
|vendor|         AMD|
|version|        4.6 (Core Profile) Mesa 21.0.1|
|cpu|              Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz|
|compiler|     gcc version 10.3.0|

Timing have been measured using DEBUG_TIME in `draw_cache_extract_mesh`.

master: `rdata 8ms iter 45ms (frame 153ms)`
this patch `rdata 6ms iter 36ms (frame 132ms)`

Reviewed By: mano-wii

Maniphest Tasks: T88352

Differential Revision: https://developer.blender.org/D11290

1 files changed, 3 insertions, 1 deletions

diff --git a/source/blender/draw/intern/draw_cache_extract_mesh.cc b/source/blender/draw/intern/draw_cache_extract_mesh.cc
index 7b2c0da4dd9..6b5877e6759 100644
--- a/source/blender/draw/intern/draw_cache_extract_mesh.cc
+++ b/source/blender/draw/intern/draw_cache_extract_mesh.cc
@@ -866,6 +866,7 @@ static void mesh_buffer_cache_create_requested(struct TaskGraph *task_graph,
    */
   const bool do_hq_normals = (scene->r.perf_flag & SCE_PERF_HQ_NORMALS) != 0 ||
                              GPU_use_hq_normals_workaround();
+  const bool override_single_mat = mesh_render_mat_len_get(me) <= 1;
 
   /* Create an array containing all the extractors that needs to be executed. */
   ExtractorRunDatas extractors;
@@ -873,7 +874,8 @@ static void mesh_buffer_cache_create_requested(struct TaskGraph *task_graph,
 #define EXTRACT_ADD_REQUESTED(type, type_lowercase, name) \
   do { \
     if (DRW_##type_lowercase##_requested(mbc->type_lowercase.name)) { \
-      const MeshExtract *extractor = mesh_extract_override_get(&extract_##name, do_hq_normals); \
+      const MeshExtract *extractor = mesh_extract_override_get( \
+          &extract_##name, do_hq_normals, override_single_mat); \
       extractors.append(extractor); \
     } \
   } while (0)