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, 46 insertions, 0 deletions

diff --git a/source/blender/editors/space_view3d/drawobject.c b/source/blender/editors/space_view3d/drawobject.c
index 6b055d34b13..24e00dd49e2 100644
--- a/source/blender/editors/space_view3d/drawobject.c
+++ b/source/blender/editors/space_view3d/drawobject.c
@@ -2403,6 +2403,48 @@ static int draw_dm_test_freestyle_face_mark(BMesh *bm, BMFace *efa)
 
 #endif
 
+/* Draw loop normals. */
+static void draw_dm_loop_normals(BMEditMesh *em, Scene *scene, Object *ob, DerivedMesh *dm)
+{
+	/* XXX Would it be worth adding a dm->foreachMappedLoop func just for this? I doubt it... */
+
+	/* We can't use dm->getLoopDataLayout(dm) here, we want to always access dm->loopData, EditDerivedBMesh would
+	 * return loop data from bmesh itself. */
+	float (*lnors)[3] = DM_get_loop_data_layer(dm, CD_NORMAL);
+
+	if (lnors) {
+		drawDMNormal_userData data;
+		MLoop *mloops = dm->getLoopArray(dm);
+		MVert *mverts = dm->getVertArray(dm);
+		int i, totloops = dm->getNumLoops(dm);
+
+		data.bm = em->bm;
+		data.normalsize = scene->toolsettings->normalsize;
+
+		calcDrawDMNormalScale(ob, &data);
+
+		glBegin(GL_LINES);
+		for (i = 0; i < totloops; i++, mloops++, lnors++) {
+			float no[3];
+			float *co = mverts[mloops->v].co;
+
+			if (!data.uniform_scale) {
+				mul_v3_m3v3(no, data.tmat, (float *)lnors);
+				normalize_v3(no);
+				mul_m3_v3(data.imat, no);
+			}
+			else {
+				copy_v3_v3(no,(float *)lnors);
+			}
+			mul_v3_fl(no, data.normalsize);
+			add_v3_v3(no, co);
+			glVertex3fv(co);
+			glVertex3fv(no);
+		}
+		glEnd();
+	}
+}
+
 /* Draw faces with color set based on selection
  * return 2 for the active face so it renders with stipple enabled */
 static DMDrawOption draw_dm_faces_sel__setDrawOptions(void *userData, int index)
@@ -3351,6 +3393,10 @@ static void draw_em_fancy(Scene *scene, ARegion *ar, View3D *v3d,
 			UI_ThemeColor(TH_VNORMAL);
 			draw_dm_vert_normals(em, scene, ob, cageDM);
 		}
+		if (me->drawflag & ME_DRAW_LNORMALS) {
+			UI_ThemeColor(TH_VNORMAL);
+			draw_dm_loop_normals(em, scene, ob, cageDM);
+		}
 
 		if ((me->drawflag & (ME_DRAWEXTRA_EDGELEN |
 		                     ME_DRAWEXTRA_FACEAREA |