From 18cccafeaf0ebcc207e894b06f55673d78b0206d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sybren=20A=2E=20St=C3=BCvel?= <sybren@blender.org>
Date: Tue, 7 May 2024 14:23:27 +0200
Subject: [PATCH] Refactor: Lattice deform: prevent incrementing nullptr

The lattice deform code would always call `co += 3` in a loop, even when
co is `nullptr`. This is invoking undefined behaviour, and causes UBSAN
warnings.

Pull Request: https://projects.blender.org/blender/blender/pulls/121396
---
 source/blender/blenkernel/intern/lattice_deform.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/source/blender/blenkernel/intern/lattice_deform.cc b/source/blender/blenkernel/intern/lattice_deform.cc
index ac0328c7a9c..e6c2c97c97d 100644
--- a/source/blender/blenkernel/intern/lattice_deform.cc
+++ b/source/blender/blenkernel/intern/lattice_deform.cc
@@ -113,11 +113,12 @@ LatticeDeformData *BKE_lattice_deform_data_create(const Object *oblatt, const Ob
 
   for (w = 0, fw = lt->fw; w < lt->pntsw; w++, fw += lt->dw) {
     for (v = 0, fv = lt->fv; v < lt->pntsv; v++, fv += lt->dv) {
-      for (u = 0, fu = lt->fu; u < lt->pntsu; u++, co += 3, fp += 3, fu += lt->du) {
+      for (u = 0, fu = lt->fu; u < lt->pntsu; u++, fp += 3, fu += lt->du) {
         if (dl) {
           fp[0] = co[0] - fu;
           fp[1] = co[1] - fv;
           fp[2] = co[2] - fw;
+          co += 3;
         }
         else {
           fp[0] = bp->vec[0] - fu;