1 files changed, 57 insertions, 4 deletions
diff --git a/source/blender/blenkernel/intern/hair.c b/source/blender/blenkernel/intern/hair.c
index 5cdb7761540..808c0347a37 100644
--- a/source/blender/blenkernel/intern/hair.c
+++ b/source/blender/blenkernel/intern/hair.c
@@ -247,12 +247,65 @@ Hair *BKE_hair_copy_for_eval(Hair *hair_src, bool reference)
   return result;
 }
 
-static Hair *hair_evaluate_modifiers(struct Depsgraph *UNUSED(depsgraph),
-                                     struct Scene *UNUSED(scene),
-                                     Object *UNUSED(object),
+static Hair *hair_evaluate_modifiers(struct Depsgraph *depsgraph,
+                                     struct Scene *scene,
+                                     Object *object,
                                      Hair *hair_input)
 {
-  return hair_input;
+  Hair *hair = hair_input;
+
+  /* Modifier evaluation modes. */
+  const bool use_render = (DEG_get_mode(depsgraph) == DAG_EVAL_RENDER);
+  const int required_mode = use_render ? eModifierMode_Render : eModifierMode_Realtime;
+  ModifierApplyFlag apply_flag = use_render ? MOD_APPLY_RENDER : MOD_APPLY_USECACHE;
+  const ModifierEvalContext mectx = {depsgraph, object, apply_flag};
+
+  /* Get effective list of modifiers to execute. Some effects like shape keys
+   * are added as virtual modifiers before the user created modifiers. */
+  VirtualModifierData virtualModifierData;
+  ModifierData *md = BKE_modifiers_get_virtual_modifierlist(object, &virtualModifierData);
+
+  /* Evaluate modifiers. */
+  for (; md; md = md->next) {
+    const ModifierTypeInfo *mti = BKE_modifier_get_info(md->type);
+
+    if (!BKE_modifier_is_enabled(scene, md, required_mode)) {
+      continue;
+    }
+
+    if ((mti->type == eModifierTypeType_OnlyDeform) &&
+        (mti->flags & eModifierTypeFlag_AcceptsVertexCosOnly)) {
+      /* Ensure we are not modifying the input. */
+      if (hair == hair_input) {
+        hair = BKE_hair_copy_for_eval(hair, true);
+      }
+
+      /* Ensure we are not overwriting referenced data. */
+      CustomData_duplicate_referenced_layer(&hair->pdata, CD_LOCATION, hair->totpoint);
+      BKE_hair_update_customdata_pointers(hair);
+
+      /* Created deformed coordinates array on demand. */
+      mti->deformVerts(md, &mectx, NULL, hair->co, hair->totpoint);
+    }
+    else if (mti->modifyHair) {
+      /* Ensure we are not modifying the input. */
+      if (hair == hair_input) {
+        hair = BKE_hair_copy_for_eval(hair, true);
+      }
+
+      Hair *hair_next = mti->modifyHair(md, &mectx, hair);
+
+      if (hair_next && hair_next != hair) {
+        /* If the modifier returned a new hair, release the old one. */
+        if (hair != hair_input) {
+          BKE_id_free(NULL, hair);
+        }
+        hair = hair_next;
+      }
+    }
+  }
+
+  return hair;
 }
 
 void BKE_hair_data_update(struct Depsgraph *depsgraph, struct Scene *scene, Object *object)