Fix T77893: Crash drawmanager threading custom data

Tangent normals were temporarily saved in the original given layers but
the typeinfo wasn't updated. This lead to several issues since we
changed the threading of the mesh extraction.

This patch stores the tangent normals in a temporary custom data on the
stack this way the typemap doesn't need to be updated.

Still need to run the tests for an hour to see if it is fixed

Reviewed By: Clément Foucault, Philipp Oeser

Differential Revision: https://developer.blender.org/D8095

1 files changed, 10 insertions, 8 deletions

diff --git a/source/blender/draw/intern/draw_cache_extract_mesh.c b/source/blender/draw/intern/draw_cache_extract_mesh.c
index f6dc4a5cfd2..e1f0cc98745 100644
--- a/source/blender/draw/intern/draw_cache_extract_mesh.c
+++ b/source/blender/draw/intern/draw_cache_extract_mesh.c
@@ -2010,8 +2010,9 @@ static void extract_tan_ex(const MeshRenderData *mr, GPUVertBuf *vbo, const bool
   }
 
   /* Start Fresh */
-  CustomData_free_layers(cd_ldata, CD_TANGENT, mr->loop_len);
-
+  CustomData loop_data;
+  CustomData_reset(&loop_data);
+  CustomData *ldata = cd_ldata;
   if (tan_len != 0 || use_orco_tan) {
     short tangent_mask = 0;
     bool calc_active_tangent = false;
@@ -2041,9 +2042,10 @@ static void extract_tan_ex(const MeshRenderData *mr, GPUVertBuf *vbo, const bool
                                     mr->poly_normals,
                                     mr->loop_normals,
                                     orco,
-                                    cd_ldata,
+                                    &loop_data,
                                     mr->loop_len,
                                     &tangent_mask);
+      ldata = &loop_data;
     }
   }
 
@@ -2075,7 +2077,7 @@ static void extract_tan_ex(const MeshRenderData *mr, GPUVertBuf *vbo, const bool
     short(*tan_data)[4] = (short(*)[4])vbo->data;
     for (int i = 0; i < tan_len; i++) {
       const char *name = tangent_names[i];
-      float(*layer_data)[4] = (float(*)[4])CustomData_get_layer_named(cd_ldata, CD_TANGENT, name);
+      float(*layer_data)[4] = (float(*)[4])CustomData_get_layer_named(ldata, CD_TANGENT, name);
       for (int l = 0; l < mr->loop_len; l++) {
         normal_float_to_short_v3(*tan_data, layer_data[l]);
         (*tan_data)[3] = (layer_data[l][3] > 0.0f) ? SHRT_MAX : SHRT_MIN;
@@ -2083,7 +2085,7 @@ static void extract_tan_ex(const MeshRenderData *mr, GPUVertBuf *vbo, const bool
       }
     }
     if (use_orco_tan) {
-      float(*layer_data)[4] = (float(*)[4])CustomData_get_layer_n(cd_ldata, CD_TANGENT, 0);
+      float(*layer_data)[4] = (float(*)[4])CustomData_get_layer_n(ldata, CD_TANGENT, 0);
       for (int l = 0; l < mr->loop_len; l++) {
         normal_float_to_short_v3(*tan_data, layer_data[l]);
         (*tan_data)[3] = (layer_data[l][3] > 0.0f) ? SHRT_MAX : SHRT_MIN;
@@ -2095,7 +2097,7 @@ static void extract_tan_ex(const MeshRenderData *mr, GPUVertBuf *vbo, const bool
     GPUPackedNormal *tan_data = (GPUPackedNormal *)vbo->data;
     for (int i = 0; i < tan_len; i++) {
       const char *name = tangent_names[i];
-      float(*layer_data)[4] = (float(*)[4])CustomData_get_layer_named(cd_ldata, CD_TANGENT, name);
+      float(*layer_data)[4] = (float(*)[4])CustomData_get_layer_named(ldata, CD_TANGENT, name);
       for (int l = 0; l < mr->loop_len; l++) {
         *tan_data = GPU_normal_convert_i10_v3(layer_data[l]);
         tan_data->w = (layer_data[l][3] > 0.0f) ? 1 : -2;
@@ -2103,7 +2105,7 @@ static void extract_tan_ex(const MeshRenderData *mr, GPUVertBuf *vbo, const bool
       }
     }
     if (use_orco_tan) {
-      float(*layer_data)[4] = (float(*)[4])CustomData_get_layer_n(cd_ldata, CD_TANGENT, 0);
+      float(*layer_data)[4] = (float(*)[4])CustomData_get_layer_n(ldata, CD_TANGENT, 0);
       for (int l = 0; l < mr->loop_len; l++) {
         *tan_data = GPU_normal_convert_i10_v3(layer_data[l]);
         tan_data->w = (layer_data[l][3] > 0.0f) ? 1 : -2;
@@ -2112,7 +2114,7 @@ static void extract_tan_ex(const MeshRenderData *mr, GPUVertBuf *vbo, const bool
     }
   }
 
-  CustomData_free_layers(cd_ldata, CD_TANGENT, mr->loop_len);
+  CustomData_free(&loop_data, mr->loop_len);
 }
 
 static void *extract_tan_init(const MeshRenderData *mr, void *buf)