Fix T78054: Crash Editing Instanced Objects with Tangent Normals

Similar track as for normal mesh. Don't store the tangent normals in CustomData
of the mesh, but in an unassociated CustomData instance.

Reviewed By: Clément Foucault

Differential Revision: https://developer.blender.org/D8161

1 files changed, 8 insertions, 9 deletions

diff --git a/source/blender/draw/intern/draw_cache_extract_mesh.c b/source/blender/draw/intern/draw_cache_extract_mesh.c
index c92722fad7e..98da668f78f 100644
--- a/source/blender/draw/intern/draw_cache_extract_mesh.c
+++ b/source/blender/draw/intern/draw_cache_extract_mesh.c
@@ -2356,7 +2356,6 @@ static void extract_tan_ex(const MeshRenderData *mr, GPUVertBuf *vbo, const bool
   /* Start Fresh */
   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;
@@ -2368,7 +2367,7 @@ 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);
     }
@@ -2389,13 +2388,12 @@ static void extract_tan_ex(const MeshRenderData *mr, GPUVertBuf *vbo, const bool
                                     &loop_data,
                                     mr->loop_len,
                                     &tangent_mask);
-      ldata = &loop_data;
     }
   }
 
   if (use_orco_tan) {
     char attr_name[32], attr_safe_name[GPU_MAX_SAFE_ATTR_NAME];
-    const char *layer_name = CustomData_get_layer_name(cd_ldata, CD_TANGENT, 0);
+    const char *layer_name = CustomData_get_layer_name(&loop_data, CD_TANGENT, 0);
     GPU_vertformat_safe_attr_name(layer_name, attr_safe_name, GPU_MAX_SAFE_ATTR_NAME);
     BLI_snprintf(attr_name, sizeof(*attr_name), "t%s", attr_safe_name);
     GPU_vertformat_attr_add(&format, attr_name, comp_type, 4, fetch_mode);
@@ -2421,7 +2419,8 @@ 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(ldata, CD_TANGENT, name);
+      float(*layer_data)[4] = (float(*)[4])CustomData_get_layer_named(
+          &loop_data, CD_TANGENT, name);
       for (int ml_index = 0; ml_index < mr->loop_len; ml_index++) {
         normal_float_to_short_v3(*tan_data, layer_data[ml_index]);
         (*tan_data)[3] = (layer_data[ml_index][3] > 0.0f) ? SHRT_MAX : SHRT_MIN;
@@ -2429,7 +2428,7 @@ 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(ldata, CD_TANGENT, 0);
+      float(*layer_data)[4] = (float(*)[4])CustomData_get_layer_n(&loop_data, CD_TANGENT, 0);
       for (int ml_index = 0; ml_index < mr->loop_len; ml_index++) {
         normal_float_to_short_v3(*tan_data, layer_data[ml_index]);
         (*tan_data)[3] = (layer_data[ml_index][3] > 0.0f) ? SHRT_MAX : SHRT_MIN;
@@ -2441,7 +2440,8 @@ 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(ldata, CD_TANGENT, name);
+      float(*layer_data)[4] = (float(*)[4])CustomData_get_layer_named(
+          &loop_data, CD_TANGENT, name);
       for (int ml_index = 0; ml_index < mr->loop_len; ml_index++) {
         *tan_data = GPU_normal_convert_i10_v3(layer_data[ml_index]);
         tan_data->w = (layer_data[ml_index][3] > 0.0f) ? 1 : -2;
@@ -2449,7 +2449,7 @@ 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(ldata, CD_TANGENT, 0);
+      float(*layer_data)[4] = (float(*)[4])CustomData_get_layer_n(&loop_data, CD_TANGENT, 0);
       for (int ml_index = 0; ml_index < mr->loop_len; ml_index++) {
         *tan_data = GPU_normal_convert_i10_v3(layer_data[ml_index]);
         tan_data->w = (layer_data[ml_index][3] > 0.0f) ? 1 : -2;
@@ -2458,7 +2458,6 @@ static void extract_tan_ex(const MeshRenderData *mr, GPUVertBuf *vbo, const bool
     }
   }
 
-  CustomData_free_layers(ldata, CD_TANGENT, mr->loop_len);
   CustomData_free(&loop_data, mr->loop_len);
 }