Mesh: don't compute CD_ORCO layer when there are no deforming modifiers

This saves memory and evaluation time for simple static meshes with e.g. a
subdivision surface modifier. If no CD_ORCO layer exists then we assume the
actual vertex coordinates are equal to the original undeformed coordinates.

1 files changed, 17 insertions, 2 deletions

diff --git a/source/blender/blenkernel/intern/modifier.c b/source/blender/blenkernel/intern/modifier.c
index 43a5e1d6592..24ba7209619 100644
--- a/source/blender/blenkernel/intern/modifier.c
+++ b/source/blender/blenkernel/intern/modifier.c
@@ -530,13 +530,14 @@ bool modifier_isEnabled(const struct Scene *scene, ModifierData *md, int require
 CDMaskLink *modifiers_calcDataMasks(struct Scene *scene,
                                     Object *ob,
                                     ModifierData *md,
-                                    const CustomData_MeshMasks *dataMask,
+                                    CustomData_MeshMasks *final_datamask,
                                     int required_mode,
                                     ModifierData *previewmd,
                                     const CustomData_MeshMasks *previewmask)
 {
   CDMaskLink *dataMasks = NULL;
   CDMaskLink *curr, *prev;
+  bool have_deform_modifier = false;
 
   /* build a list of modifier data requirements in reverse order */
   for (; md; md = md->next) {
@@ -545,6 +546,10 @@ CDMaskLink *modifiers_calcDataMasks(struct Scene *scene,
     curr = MEM_callocN(sizeof(CDMaskLink), "CDMaskLink");
 
     if (modifier_isEnabled(scene, md, required_mode)) {
+      if (mti->type == eModifierTypeType_OnlyDeform) {
+        have_deform_modifier = true;
+      }
+
       if (mti->requiredDataMask) {
         mti->requiredDataMask(ob, md, &curr->mask);
       }
@@ -554,11 +559,21 @@ CDMaskLink *modifiers_calcDataMasks(struct Scene *scene,
       }
     }
 
+    if (!have_deform_modifier) {
+      /* Don't create orco layer when there is no deformation, we fall
+       * back to regular vertex coordinates */
+      curr->mask.vmask &= ~CD_MASK_ORCO;
+    }
+
     /* prepend new datamask */
     curr->next = dataMasks;
     dataMasks = curr;
   }
 
+  if (!have_deform_modifier) {
+    final_datamask->vmask &= ~CD_MASK_ORCO;
+  }
+
   /* build the list of required data masks - each mask in the list must
    * include all elements of the masks that follow it
    *
@@ -570,7 +585,7 @@ CDMaskLink *modifiers_calcDataMasks(struct Scene *scene,
       CustomData_MeshMasks_update(&curr->mask, &prev->mask);
     }
     else {
-      CustomData_MeshMasks_update(&curr->mask, dataMask);
+      CustomData_MeshMasks_update(&curr->mask, final_datamask);
     }
   }