Fix T95644: Cycles doesn't update modified object attributes on GPU

evice_update_preprocess is supposed to detect modified attributes and flag the
device_vector for a copy through device_update_flags. However, since object
attributes are only created in device_update_attributes afterwards, they can't
be included in that check.

Change the function that actually updates the device_vector to tag it as
modified as soon as its content gets updated.

Differential Revision: https://developer.blender.org/D14815

intern/cycles/scene/geometry.cpp

@@ -618,6 +618,7 @@ void GeometryManager::update_attribute_element_offset(Geometry *geom,
         for (size_t k = 0; k < size; k++) {
           attr_uchar4[offset + k] = data[k];
         }
+        attr_uchar4.tag_modified();
       }
       attr_uchar4_offset += size;
     }
@@ -630,6 +631,7 @@ void GeometryManager::update_attribute_element_offset(Geometry *geom,
         for (size_t k = 0; k < size; k++) {
           attr_float[offset + k] = data[k];
         }
+        attr_float.tag_modified();
       }
       attr_float_offset += size;
     }
@@ -642,6 +644,7 @@ void GeometryManager::update_attribute_element_offset(Geometry *geom,
         for (size_t k = 0; k < size; k++) {
           attr_float2[offset + k] = data[k];
         }
+        attr_float2.tag_modified();
       }
       attr_float2_offset += size;
     }
@@ -654,6 +657,7 @@ void GeometryManager::update_attribute_element_offset(Geometry *geom,
         for (size_t k = 0; k < size * 3; k++) {
           attr_float4[offset + k] = (&tfm->x)[k];
         }
+        attr_float4.tag_modified();
       }
       attr_float4_offset += size * 3;
     }
@@ -666,6 +670,7 @@ void GeometryManager::update_attribute_element_offset(Geometry *geom,
         for (size_t k = 0; k < size; k++) {
           attr_float4[offset + k] = data[k];
         }
+        attr_float4.tag_modified();
       }
       attr_float4_offset += size;
     }
@@ -678,6 +683,7 @@ void GeometryManager::update_attribute_element_offset(Geometry *geom,
         for (size_t k = 0; k < size; k++) {
           attr_float3[offset + k] = data[k];
         }
+        attr_float3.tag_modified();
       }
       attr_float3_offset += size;
     }