Split Normals I (1/5): basis for split normals (nearly nothing user-visible here):

* Add a new calcLoopNormals function to DerivedMesh struct, and implement it for CDDM and CCGDM (subsurf).
  EditDerivedBMesh (edit mode DM) only gets a dummy one in this commit.
* Add a tessellated version of CD_LOOPNORMAL layer (CD_TESSLOOPNORMAL), with relevant code to handle it
  (tessellation, rna access, etc.).
* Change auto_smooth options of Mesh (angle now in radian internaly, and toggle is now used to enable/disable
  split normals in DM creation process). Note BI render code is not touched here, hence its behavior regarding
  this option is now incoherent, will be addressed in a separate commit.

Reviewers: campbellbarton

CC: brecht

Differential Revision: https://developer.blender.org/D365

1 files changed, 36 insertions, 3 deletions

diff --git a/source/blender/blenkernel/intern/mesh_evaluate.c b/source/blender/blenkernel/intern/mesh_evaluate.c
index 5d10c12b8e0..edd0a8540e3 100644
--- a/source/blender/blenkernel/intern/mesh_evaluate.c
+++ b/source/blender/blenkernel/intern/mesh_evaluate.c
@@ -574,6 +574,7 @@ void BKE_mesh_normals_loop_split(MVert *mverts, const int UNUSED(numVerts), MEdg
 #undef IS_EDGE_SHARP
 }
 
+
 /** \} */
 
 
@@ -1103,7 +1104,8 @@ void BKE_mesh_loops_to_mface_corners(
         const int numTex, /* CustomData_number_of_layers(pdata, CD_MTEXPOLY) */
         const int numCol, /* CustomData_number_of_layers(ldata, CD_MLOOPCOL) */
         const bool hasPCol, /* CustomData_has_layer(ldata, CD_PREVIEW_MLOOPCOL) */
-        const bool hasOrigSpace /* CustomData_has_layer(ldata, CD_ORIGSPACE_MLOOP) */
+        const bool hasOrigSpace, /* CustomData_has_layer(ldata, CD_ORIGSPACE_MLOOP) */
+        const bool hasLNor /* CustomData_has_layer(ldata, CD_NORMAL) */
 )
 {
 	MTFace *texface;
@@ -1152,6 +1154,14 @@ void BKE_mesh_loops_to_mface_corners(
 			copy_v2_v2(of->uv[j], lof->uv);
 		}
 	}
+
+	if (hasLNor) {
+		short (*tlnors)[3] = CustomData_get(fdata, findex, CD_TESSLOOPNORMAL);
+
+		for (j = 0; j < mf_len; j++) {
+			normal_float_to_short_v3(tlnors[j], CustomData_get(ldata, (int)lindex[j], CD_NORMAL));
+		}
+	}
 }
 
 /**
@@ -1172,6 +1182,7 @@ void BKE_mesh_loops_to_tessdata(CustomData *fdata, CustomData *ldata, CustomData
 	const int numCol = CustomData_number_of_layers(ldata, CD_MLOOPCOL);
 	const bool hasPCol = CustomData_has_layer(ldata, CD_PREVIEW_MLOOPCOL);
 	const bool hasOrigSpace = CustomData_has_layer(ldata, CD_ORIGSPACE_MLOOP);
+	const bool hasLoopNormal = CustomData_has_layer(ldata, CD_NORMAL);
 	int findex, i, j;
 	int *pidx;
 	unsigned int (*lidx)[4];
@@ -1225,6 +1236,17 @@ void BKE_mesh_loops_to_tessdata(CustomData *fdata, CustomData *ldata, CustomData
 			}
 		}
 	}
+
+	if (hasLoopNormal) {
+		short (*fnors)[4][3] = CustomData_get_layer(fdata, CD_TESSLOOPNORMAL);
+		float (*lnors)[3] = CustomData_get_layer(ldata, CD_NORMAL);
+
+		for (findex = 0, lidx = loopindices; findex < num_faces; lidx++, findex++, fnors++) {
+			for (j = (*lidx)[3] ? 4 : 3; j--;) {
+				normal_float_to_short_v3((*fnors)[j], lnors[(*lidx)[j]]);
+			}
+		}
+	}
 }
 
 /**
@@ -1516,6 +1538,7 @@ int BKE_mesh_mpoly_to_mface(struct CustomData *fdata, struct CustomData *ldata,
 	const int numCol = CustomData_number_of_layers(ldata, CD_MLOOPCOL);
 	const bool hasPCol = CustomData_has_layer(ldata, CD_PREVIEW_MLOOPCOL);
 	const bool hasOrigSpace = CustomData_has_layer(ldata, CD_ORIGSPACE_MLOOP);
+	const bool hasLNor = CustomData_has_layer(ldata, CD_NORMAL);
 
 	/* over-alloc, ngons will be skipped */
 	mface = MEM_mallocN(sizeof(*mface) * (size_t)totpoly, __func__);
@@ -1575,7 +1598,7 @@ int BKE_mesh_mpoly_to_mface(struct CustomData *fdata, struct CustomData *ldata,
 
 				BKE_mesh_loops_to_mface_corners(fdata, ldata, pdata,
 				                                lindex, k, i, 3,
-				                                numTex, numCol, hasPCol, hasOrigSpace);
+				                                numTex, numCol, hasPCol, hasOrigSpace, hasLNor);
 				test_index_face(mf, fdata, k, 3);
 			}
 			else {
@@ -1595,7 +1618,7 @@ int BKE_mesh_mpoly_to_mface(struct CustomData *fdata, struct CustomData *ldata,
 
 				BKE_mesh_loops_to_mface_corners(fdata, ldata, pdata,
 				                                lindex, k, i, 4,
-				                                numTex, numCol, hasPCol, hasOrigSpace);
+				                                numTex, numCol, hasPCol, hasOrigSpace, hasLNor);
 				test_index_face(mf, fdata, k, 4);
 			}
 
@@ -1651,6 +1674,16 @@ static void bm_corners_to_loops_ex(ID *id, CustomData *fdata, CustomData *ldata,
 		}
 	}
 
+	if (CustomData_has_layer(fdata, CD_TESSLOOPNORMAL)) {
+		float (*lnors)[3] = CustomData_get(ldata, loopstart, CD_NORMAL);
+		short (*tlnors)[3] = CustomData_get(fdata, findex, CD_TESSLOOPNORMAL);
+		const int max = mf->v4 ? 4 : 3;
+
+		for (i = 0; i < max; i++, lnors++, tlnors++) {
+			normal_short_to_float_v3(*lnors, *tlnors);
+		}
+	}
+
 	if (CustomData_has_layer(fdata, CD_MDISPS)) {
 		MDisps *ld = CustomData_get(ldata, loopstart, CD_MDISPS);
 		MDisps *fd = CustomData_get(fdata, findex, CD_MDISPS);