[Bf-blender-cvs] [a81cc5cbcb6] blender-v3.1-release: Fix: Avoid potential use of dirty normals

[Hans Goudey]

Commit: a81cc5cbcb6c9e9ef4bee610ac1d325d33884e98
Author: Hans Goudey
Date:   Mon Feb 21 11:40:59 2022 -0500
Branches: blender-v3.1-release
https://developer.blender.org/rBa81cc5cbcb6c9e9ef4bee610ac1d325d33884e98

Fix: Avoid potential use of dirty normals

Instead of accessing the `CD_NORMAL` layer directly,
use the proper API for accessing mesh normals. Even if the
layer exists, the values might be incorrect due to a deformation.
Related to ef0e21f0ae71d, 969c4a45ce09100e, and T95839.

===================================================================

M	source/blender/python/mathutils/mathutils_bvhtree.c
M	source/blender/render/intern/bake.c
M	source/blender/render/intern/multires_bake.c

===================================================================

diff --git a/source/blender/python/mathutils/mathutils_bvhtree.c b/source/blender/python/mathutils/mathutils_bvhtree.c
index 588d3753eab..28687ce2d13 100644
--- a/source/blender/python/mathutils/mathutils_bvhtree.c
+++ b/source/blender/python/mathutils/mathutils_bvhtree.c
@@ -1180,10 +1180,8 @@ static PyObject *C_BVHTree_FromObject(PyObject *UNUSED(cls), PyObject *args, PyO
     tree = BLI_bvhtree_new((int)tris_len, epsilon, PY_BVH_TREE_TYPE_DEFAULT, PY_BVH_AXIS_DEFAULT);
     if (tree) {
       orig_index = MEM_mallocN(sizeof(*orig_index) * (size_t)tris_len, __func__);
-      CustomData *pdata = &mesh->pdata;
-      orig_normal = CustomData_get_layer(pdata, CD_NORMAL); /* can be NULL */
-      if (orig_normal) {
-        orig_normal = MEM_dupallocN(orig_normal);
+      if (!BKE_mesh_poly_normals_are_dirty(mesh)) {
+        orig_normal = MEM_dupallocN(BKE_mesh_poly_normals_ensure(mesh));
       }
 
       for (i = 0; i < tris_len; i++, lt++) {
diff --git a/source/blender/render/intern/bake.c b/source/blender/render/intern/bake.c
index 883e026472b..b11d9629e03 100644
--- a/source/blender/render/intern/bake.c
+++ b/source/blender/render/intern/bake.c
@@ -482,7 +482,9 @@ static TriTessFace *mesh_calc_tri_tessface(Mesh *me, bool tangent, Mesh *me_eval
   looptri = MEM_mallocN(sizeof(*looptri) * tottri, __func__);
   triangles = MEM_callocN(sizeof(TriTessFace) * tottri, __func__);
 
-  const float(*precomputed_normals)[3] = CustomData_get_layer(&me->pdata, CD_NORMAL);
+  const float(*precomputed_normals)[3] = BKE_mesh_poly_normals_are_dirty(me) ?
+                                             NULL :
+                                             BKE_mesh_poly_normals_ensure(me);
   const bool calculate_normal = precomputed_normals ? false : true;
 
   if (precomputed_normals != NULL) {
diff --git a/source/blender/render/intern/multires_bake.c b/source/blender/render/intern/multires_bake.c
index 9468e4c5b0f..73f925f5905 100644
--- a/source/blender/render/intern/multires_bake.c
+++ b/source/blender/render/intern/multires_bake.c
@@ -483,7 +483,6 @@ static void do_multires_bake(MultiresBakeRender *bkr,
     MPoly *mpoly = dm->getPolyArray(dm);
     MLoop *mloop = dm->getLoopArray(dm);
     MLoopUV *mloopuv = dm->getLoopDataArray(dm, CD_MLOOPUV);
-    const float *precomputed_normals = dm->getPolyDataArray(dm, CD_NORMAL);
     float *pvtangent = NULL;
 
     ListBase threads;
@@ -498,6 +497,7 @@ static void do_multires_bake(MultiresBakeRender *bkr,
     memcpy(temp_mesh->mpoly, dm->getPolyArray(dm), temp_mesh->totpoly * sizeof(*temp_mesh->mpoly));
     memcpy(temp_mesh->mloop, dm->getLoopArray(dm), temp_mesh->totloop * sizeof(*temp_mesh->mloop));
     const float(*vert_normals)[3] = BKE_mesh_vertex_normals_ensure(temp_mesh);
+    const float(*poly_normals)[3] = BKE_mesh_poly_normals_ensure(temp_mesh);
 
     if (require_tangent) {
       if (CustomData_get_layer_index(&dm->loopData, CD_TANGENT) == -1) {
@@ -513,7 +513,7 @@ static void do_multires_bake(MultiresBakeRender *bkr,
             NULL,
             0,
             vert_normals,
-            (const float(*)[3])CustomData_get_layer(&dm->polyData, CD_NORMAL),
+            poly_normals,
             (const float(*)[3])dm->getLoopDataArray(dm, CD_NORMAL),
             (const float(*)[3])dm->getVertDataArray(dm, CD_ORCO), /* may be nullptr */
             /* result */
@@ -558,7 +558,7 @@ static void do_multires_bake(MultiresBakeRender *bkr,
       handle->data.mlooptri = mlooptri;
       handle->data.mloop = mloop;
       handle->data.pvtangent = pvtangent;
-      handle->data.precomputed_normals = precomputed_normals; /* don't strictly need this */
+      handle->data.precomputed_normals = (float *)poly_normals; /* don't strictly need this */
       handle->data.w = ibuf->x;
       handle->data.h = ibuf->y;
       handle->data.lores_dm = dm;