Fix: SubDiv: Out of bound write loose normals

Updating loose normals leads to out of bound writes on the GPU.
The reason is that normals are float3, but the code assumed
they were float4.

Pull Request: https://projects.blender.org/blender/blender/pulls/144128

source/blender/draw/intern/mesh_extractors/extract_mesh_vbo_lnor.cc

@@ -299,11 +299,11 @@ static void update_loose_normals(const MeshRenderData &mr,
 
   /* Default to zeroed attribute. The overlay shader should expect this and render engines should
    * never draw loose geometry. */
-  const float4 default_normal(0.0f, 0.0f, 0.0f, 0.0f);
+  const float3 default_normal(0.0f, 0.0f, 0.0f);
   for (const int i : IndexRange::from_begin_end(loose_geom_start, vbo_size)) {
     /* TODO(fclem): This has HORRENDOUS performance. Prefer clearing the buffer on device with
      * something like glClearBufferSubData. */
-    GPU_vertbuf_update_sub(&lnor, i * sizeof(float4), sizeof(float4), &default_normal);
+    GPU_vertbuf_update_sub(&lnor, i * sizeof(float3), sizeof(float3), &default_normal);
   }
 }
 

source/blender/gpu/vulkan/vk_vertex_buffer.cc

@@ -73,6 +73,8 @@ void VKVertexBuffer::update_sub(uint start_offset, uint data_size_in_bytes, cons
     /* Allocating huge buffers can fail, in that case we skip copying data. */
     return;
   }
+  BLI_assert_msg(start_offset + data_size_in_bytes <= buffer_.size_in_bytes(),
+                 "Out of bound write to vertex buffer");
   if (buffer_.is_mapped()) {
     buffer_.update_sub_immediately(start_offset, data_size_in_bytes, data);
   }